eChapters

ABSTRACT

Aloe vera is one of the oldest known therapeutic herb belongs to the family Liliaceae commonly known as guar patta. Gel from fleshy leaves of Aloe vera is rich in 200 nutrients which are used in healing the burns, wounds, gastric ulcers, treatment of diabetes and also used in normal functioning of the liver. Aloe vera is a desert plant which needs water in very less quantity. As Aloe vera is second in ranking in drug production in the world. Government of India is also trying to promote Aloe vera as a crop in dry and semi dry regions of India. As it needs very less and cheaper inputs, Aloe farming promises higher economic gains to farmers. But as the plant grows vegetatively the quality planting material is a problem. Tissue culture provides an opportunity in production of quality seedlings. To optimize the regeneration system in Aloe vera, MS based media were tried to induce shoot formation in cultured shoot tip explants. 6-10 cm long offshoots were collected. Shoot tip explants were cut vertically after sterilization in laminar hood and cultured on MS basal media supplemented with various growth regulators. A total of 23 media were tried for shoot regeneration. All the cultures were incubated under fluorescent light. Different concentrations of BAP (2, 5, 10 mg/l) were used and MS medium with 2 mg/l or 5 mg/l BAP exhibited similar response while BAP at 10 mg/l showed poor shoot formation. TDZ when used at 1 mg/l concentration improved percent shoot formation marginally. Multiple shoots were observed on TDZ containing medium and BAP (2.0 mg/l) supplemented medium in 12-15 days. Multiple shoots were obtained in 12 days when 2 mg/l BAP was added along with 0.18 mg/l IAA. The number of multiple shoots ranged from 4 -15 per explant. The regenerated plants developed roots on MS medium supplemented with 0.1mg/l NAA.

ABSTRACT

Successful in vitro clonal propagation of mature tree of Lasoda (Cordia myxa Roxb) has been achieved through single node explant. Both types of organogenesis of shoot and root formation were obtained by placing nodal explant on shoot induction medium and subsequently on rooting medium. More than 90% culture were responsive for in-vitro axillary shoot proliferation on MS media supplemented with 30g Sucrose 8.0 g agar and a combination of 2.0 mg BA and 0.1 mg NAA per litre. After culture period of 6-8 week, the nodal explants with micro shoot were rooted on the MS media supplemented with30 g Sucrose + 3g activated charcol and different level of NAA (0, 1, 3 and 6 mg/ litre). The season and position of explant on the mother plant was also shown to influence in vitro performance of the regeneration in terms of establishment of aseptic culture, percentage of responsive explants and intensity of leaching of growth inhibitory phenolic chemicals.

ABSTRACT

The mass production of orchids through in vitro approach is now practising on a commercial scale. But, in most cases, it is being done via an intermediate callus which may lead to variability in the progenies. A study was made to standardize a protocol for rapid mericloning of tropical orchid dendrobium cv. sonia from the shoot tip explant without an intermediate callus so as to produce true to type progenies. The efficiency of production of clones through agar gelled medium and shake cultures were compared. The shoot tip explants produced an average of 6-8 multiple shoots on agar gelled (0.8% w/v) MS medium containing 3% sucrose as carbon source supplemented with a hormonal combination of 0.75 mg l^-1 NAA and 2.5 mg l^-1 KIN without an intervening callus, within a period of 3 - 4 months. When the shoot tip explants were cultured in agitated ( 80 - 100 rpm) liquid Vacin and Went ( VW) medium supplemented with 3% sucrose, 2.0 - 2.5 mg l^-1 BA and 0.5 - 1.0 mg l^-1 NAA could induce a large number of protocorms within a period of two weeks. Agitated liquid MS medium supplemented with 0.5 mg l ^-1 IBA and 2 mg l^-1 BA or 0.5 mg l ^-1 2,4 - D, 0.5 mg l^-1 GA₂ and 3.0 mg l^-1 BA was identified as the rapid multiplication medium of the protocorms. About 60 - 80 protocorms could be produced from a single protocorm within a period of 3 weeks. Transfer of these protocorms to agar gelled (0.8%w/v) MS medium containing 2% sucrose supplemented with 20 - 25% coconut milk (CM) was found ideal for plantlet formation of size 1.0 - 1.5 cm within a period of three weeks. Sub culturing of the plantlets to the same medium resulted in rapid profuse rooting. Transfering the rooted plants into bottles containing sterile coconut husk provided with half MS medium without sucrose and hormones was sufficient for in vitro hardening. By this two stage culturing technique, about 50 - 60 true to type clones can be produced from a single shoot apex within a period of 3 months.

ABSTRACT

In Kerala, the commercial cultivation of tomato is limited due to the bacterial wilt disease caused by the soil borne pathogen Ralstonia solanacearum. The release of bacterial wilt resistant varieties like Sakthi, Mukthi and Anagha has increased the area under tomato. But, these varieties are susceptible to tomato leaf curl virus diseases caused by Germini group virus and transmitted by white fly (Bemisia tabaci). The disease incidence varies from 10.77% to 90.5% and the yield loss is tremendous. Unless the tomato variety resistant to ToLCV disease is resistant to bacterial wilt also, it cannot be recommended for cultivation in the State.

The somaclonal variations have been well exploited in developing disease resistant varieties in many crops. Therefore an experiment was formulated to study the somaclonal variations and to screen the somaclones for resistance to tomato leaf curl virus disease in L. esculentum var. Sakthi and L. pimpinellifolium.

The somaclones of Sakthi and L. pimpinellifolium along with the parental lines were planted in earthen pots containing potting mixture with bacterial wilt sick soil. These were screened for resistance to ToLCV disease by artificial inoculation of the vector Bemisia tabaci inside the cages. The observations were recorded on ex vitro survival, biometric characters and reaction to ToLCV and other major diseases.

The ex vitro survival was 46.2% in Sakthi and 36.6% in L. pimpinellifolium. The somaclones of Sakthi showed wide variation for plant height and spread compared to that of L. pimpinellifolium. Some of the somaclones exhibited ‘gigantism’ with potato leaved plants. The yield of the somaclones of Sakthi were higher than that of parental line.

ABSTRACT

Cycas is the largest genus among cycads - the surviving remnants of an ancient line of plants of the early Mesozoic period. The IUCN has classified more than half of the 182 species of Cycadales as endangered, vulnerable or rare. The use of in vitro techniques could permit a way to conserve many of the endangered species. None of the in vitro studies has been successful in establishing a functional protocol for artificial propagation of cycads. The objective of the present investigation is to explore the possibilities of in vitro plant regeneration from megagametophyte explants of Cycas circinalis - the only species of Cycas grown in Kerala. Megagametophyte from the ovules of ten-year-old Cycas circinalis plant was used as explant. Standard tissue culture techniques were adopted for the in vitro culturing of the explant. The basal medium involved major salts of B5 and minor salts of MS media. Glutamine, casein hydrolysate, coconut water and megagametophyte extract were used as supplements. The plant growth regulators - Kn, BAP, 2iP, IAA, NAA and 2,4- D - were incorporated alone and in combinations. Highest percentage of shoot induction and highest average number of shoot buds per culture were observed in PGR combination involving Kn + BAP along with one of the auxins (2,4-D or NAA or IAA). Shoot buds developed did not show further growth even after one year. The protocol employed in the present investigation may lead to multiple shoot proliferation and help in large-scale propagation of Cycas circinalis.

ABSTRACT

To study the influence of season on explant collection, axillary buds from mature trees of three elite genotypes of tamarind viz., Sour pulped type, Red pulped type, and Sweet pulped type (Thailand) were collected monthwise from September, 2002 to August, 2003, sterilized properly and cultured in MS medium supplemented with BAP (1, 1.5, 2, 2.5 and 3 mgl^-1) + GA 0.5 mgl^-1 + NAA 0.1 mgl^-1. The studies revealed that, the bud break percentage was highly dependent on the season of explant collection. In case of Sour pulped type, bud break was recorded during the month of April, May and June. Maximum per cent bud break (50.00 per cent) was recorded in May and June but least number of days were required for bud break (12.33) in April month. In Red pulped type, the bud break was observed during February to June. The axillary buds collected and cultured during the month of February recorded the best results with respect to the per cent bud break (100 per cent) and least number of days taken for bud break (7.12 days). In Sweet pulped (Thailand) type, bud break was recorded during the months of February to June. The axillary buds collected and cultured in the month of may recorded the best results with respect to the percent bud break (87.50 per cent) but March showed least number of days for bud break. Nodal segments cultured on MS + BAP 2 mgl^-1 + GA 0.5 mgl^-1 + NAA 0.5 mgl^-1 gave maximum and early bud break in three genotypes, but sprouted shoots showed abscission of leaflets and died later on.

ABSTRACT

Rose (Rosa hybrida Linn.) is universally acclaimed as the ‘Queen of Flowers’. But this woody plant is considered less amenable to in vitro culture as compared to herbaceous plants. This is due to the fact that the establishment rose explants is difficult due to heavy phenolic exudation. In the present study, this problem was solved by a very simple and cost effective method. The cut ends of the explant were sealed with wax after thorough sterilization. Ten different explant collection periods with 20 different hormonal combinations in MS culture medium were taken for establishment. The winter dormancy period (Mid- December) was considered best for explant collection and showed 85% survival. Amongst the hormonal combinations 5mg/l BA coupled with 0.05mg/l NAA was considered the best. The average number of leaves (7.5) and average shoot length (7.3 cm) was also highest in this treatment, 15 days after culture establishment.

ABSTRACT

Haploids are of great importance in breeding programmes for the production of homozygous diploid lines. This technique reduces the time span in developing new varieties and fixes the traits including recessive ones in the homozygous condition. The haploid embryos or doubled haploid plants could be used in mutation breeding, genetic engineering, biochemical and physiological studies. Isolated microspore culture for the production of haploids has not yet been reported in Hevea brasiliensis. Hence the present work was initiated with the view of producing haploid plants by the culture of isolated pollen grains. The flower bud of the clone RRII 105 at the late uninucleate to early binucleate stage was used for culture initiation. Different pretreatment solutions were tried at different temperatures (4°C, 27°C and 33°C) with the macronutrients of N6 media. Three kinds of callus induction media were used viz. N6, WPM and Hunters medium supplemented with myoinositol (200 mg^-1), glutamate (150 mg^-1), phenyl acetic acid (7.0 mg^-1), sucrose (70 g^-1) and growth regulators. Induction medium include moving liquid, static liquid and semi- solid medium. The ovary co-culture was also tried in the induction medium to increase the frequency of callus formation. Pretreatment of the anther with 0.3 M mannitol at 33°C promoted the division of microspores. Static liquid cultures improved the formation of multicellular microspores compared to semi-solid or moving liquid cultures. N₆ basal medium supplemented with 2.0 mg/l 2.4-D and 1.0 mg/l KIN induced microcalli formation. When the ovary co-culture was included in the callus induction medium, the rate of cell proliferation was increased considerably and the duration of callus formation was reduced from 3 months to 14 days. The results of the present study throws light towards the possibility of regenerating doubled haploids in future.

ABSTRACT

Ophiorrhiza mungos is a rich source of the potent antineoplastic therapeutic agent Camptothecin, which is effective in the complete remission of lung, breast, uterine and cervical cancer. With increasing demand, most of the plants have been indiscriminately exploited from their natural habitat for the isolation of this valuable therapeutic agent. The biotechnological application such as plant tissue culture seems to be a viable option for the production of this high value therapeutic compound without destroying the natural flora. For this purpose various tissue culture techniques have been established to enhance the production of this compound from different parts of O. mungos. The present study revealed that the Physical elicitation with varying doses of irradiation is significantly higher (0.87mg/ g dry weight) than that obtained by chemical elicitation using methyle jasmonate (0.41mg/ g dry weight) compared to control. Biotic elicitors like chitin, chitosan, fungal and bacterial extracts were also used and considerable increase in the production of Camptothecin was obtained in all these cases. Permeabilization with Tween 20 found to be enhancing the exudation of camptothecin (0.021 mg/ml) compared to control (0.0003mg/ml). Hence, the present study gives an alternative for large scale production of camptothecin without affecting the natural flora in a cost effective method.

ABSTRACT

Tinospora cordifolia, a versatile medicinal species with antipyretic and immunomodulatory properties is one of the indigenous sources of the therapeutically valuable alkaloid, berberine. However, the plant contains only meagre amounts of this alkaloid. Hence upgradation of the content of berberine in Tinospora, through biotechnological interventions assumes importance. Four week old leaf, petiole and stem derived calli of two ecotypes of Tinospora viz., Vellanikkara ecotype and Madurai ecotype, subcultured on to Murashige and Skoog (MS) medium, supplemented with various growth regulators, were incubated in light and screened for the presence of berberine employing thin layer chromatography. MS medium with NAA @ 2 mg l^-1 supplemented with BA or kinetin, each at 2 mg l^-1, was identified as the basal production medium for in vitro production of berberine, yielding 7.55 μg and 7.36 μg berberine respectively, per gram of calli. Calli produced from stem segments registered maximum amount of berberine compared to leaf and petiole derived callus cultures. Increasing levels of sucrose in basal medium did not have a favourable influence on the expression of berberine in the test calli. Reducing nitrate and phosphate content of the basal medium to half their strength resulted in enhanced berberine production in in vitro cultures of both the experimental ecotypes. Favourable influence of precursor feeding on upgrading the content of berberine in leaf and stem derived calli of both the ecotypes of the experimental species was also confirmed in the study.

ABSTRACT

Cassava, sweet potato and yams are root and tuber crops propagated through vegetative parts. The CTCRI is maintaining a large collection of (3985 accessions) these crop germplasm in field gene banks. Studies were conducted to transfer these collections to in vitro storage so as to clean off systemic infection and protect them from loss due to biotic and abiotic stress. Suitable media protocols, method of surface sterilization, inoculation and incubation were developed for these different crop species in order to establish initial cultures, for their multiplication and storage under slow growth. Meristem, shoot buds and tuber sprouts were used as propagules for culture initiation.Murashige and Skoog (1962) medium was found suitable for all the species studied with variations required in the concentration of growth regulators (NAA, BA and GA ) for meristem culture and micropropagation. Slow growth of cultures was induced using osmotic retardants like mannitol and sorbitol. Addenda like silver nitrate and activated charcoal was found effective in reducing leaf chlorosis and preventing leaf shedding, thereby contributing to culture life and regeneration capacity. The slow growth media developed were effective in prolonging the subculture period to 18 months (cassava), 10 months (sweet potato), and 20 months (yams). The studies have helped in establishing 400 accessions of cassava, 272 accessions of sweet potato and 166 accessions of yams in In vitro Active Gene Bank. The results are presented and discussed.

ABSTRACT

In vitro pollination and fertilization could be a tool for heterosis breeding of triploid turmeric cultivars, which are almost non-seed setting naturally. Investigations were undertaken to optimize media combinations for the development of in vitro pollinated ovules to mature seed .The half strength MS medium supplemented with auxins and cytokinins was superior to full strength MS. The supplementation of ½ strength MS medium with either auxins or cytokinins at lower concentrations induced some ovule development. The ovule development was more when auxins and cytokinins together were given. The combination of ½ MS +3% sucrose +NAA 0.5mg l ^-1 +BAP 1mg l^-1 showed maximum ovule swelling in cultures. The combinations of BAP 4mg l^-1 with IAA 0.2mg l^-1 produced callusing instead of ovule swelling.

ABSTRACT

Lack of high yielding varieties, variation among progenies through seedling propagation and transmission of viral diseases through sucker propagation together contribute to the decline in productivity of large cardamom (Amomum subulatum Roxb). To increase the productivity of this crop, planting material raised through tissue culture techniques from few selections having higher productivity was considered. From the study, it was revealed that TC plants were superior to conventionally propagated plants due to vigorous growth during juvenile phase, precocity in the yield and higher productivity compared to that of open pollinated seedlings.

ABSTRACT

Central Plantation Crops Research Institute at Kasaragod maintains largest collection of coconut germplasm accessions representing different geographical regions. So far, morphological and isozyme markers were employed for germplasm characterization. To overcome the difficulties associated with the morphological markers, DNA based molecular markers are presently employed for germplasm characterization. In the present study, Inter Simple Sequence Repeat (ISSR) markers are utilized to estimate the genetic diversity among South East Asian germplasm accessions. Nineteen ISSR primers were used to amplify 8 germplasm accessions (4 palms per accession referred as population). The PCR products were electrophoresed in 1.80 % agarose gels. Binary data were analyzed using the software POPGENE ver. 1.32. Dendrogram was constructed based on Nei’s unbiased measure of genetic distance. Nineteen ISSR primers detected a total of 85 polymorphic markers across 32 individuals belonging to eight populations. The average genetic distance among the eight populations ranged from 0.7908 to 0.9327 with a mean of 0.8540. Of the 28 pair wise comparisons the accessions Laguna Tall and Kongthienyong Tall (KTYT) showed the highest genetic identity (0.9327). The lowest identity (0.7908) was between San Roman Tall (SNRT) and Philippines Dalig Tall (PDLT). The Shannon’s index ranged from 0.1615 to 0.299. Diversity parameters viz. number of effective alleles, gene diversity, number of polymorphic markers were calculated for each population. The dendrogram constructed based on the genetic distance revealed clustering of Kongthienyong Tall (KTYT) and Laguna Tall (LAGT) while Philippines Dalig Tall (PDLT) was positioned separately. In the genetic improvement programmes the diverse accessions can be used in hybridization for increased heterosis.

ABSTRACT

DNA based molecular marker technologies have been used extensively to study the genetic relationships and to develop markers for identification of cultivars/varieties in various crops. The present study is an attempt to assess the variability and relatedness among 49 varieties/ accessions of black pepper (Piper nigrum L) based on the data generated by both RAPD and AFLP analyses. The similarity matrix was subjected to cluster analysis and dendrogram generated using the software Ntsyspc 2.1. The dendrogram revealed an average similarity of 63 per cent among accessions. Two selections from the variety Karimunda, namely Sreekara and Subhakara, together formed a single cluster with almost 92 per cent similarity. The dissimilarity observed between the varieties Panniyur 1 and Panniyur 3 the progenies of the same parentage, Uthirankotta and Cheriyakanyakadan was only 18 per cent. Based on RAPD analysis 34 varieties were grouped into 5 clusters. Distinct clustering was not observed in AFLP analysis. The results obtained were correlated with the taxonomical interrelationships reported for these varieties. The overall study has thus helped in understanding the relationship among the local cultivars and released varieties.

ABSTRACT

Grape is a commercially cultivated fruit crop in India. As a result of large-scale introduction, the origin and authenticity of many grape varieties is unclear and the subject of some controversy. Many of the varieties were mixed up and now have led to confusion regarding their correct identification. To explore the genetic relationships between different grape varieties and to analyze their diversity, molecular marker technique has proved to be useful. In the present study, 34 grape varieties have been characterized using Inter Simple Sequence Repeat (ISSR) markers. Out of 93 ISSR primers screened initially, 11-showed good polymorphism. Total 174 bands were obtained, out of which 145 were polymorphic. The similarity indices were calculated using DICE coefficient and NTSYS Pc 2.1 software.

Cluster analysis resulted in the formation of two main clusters. One, of the varieties belonging to Vitis vinifera and other of V. labrusca. Varieties belonging to V. vinifera appeared more diverse by forming distinct sub-clusters based on their colour, flavour and seeds. Out of 34 varieties screened, 10 varieties are grouped in white berries cluster and 15 in coloured (red /black) berries cluster. Three white varieties- Italia, Queen of Vineyard and Thompson seedless are grouped into cluster of coloured varieties. The cluster of labrusca varieties showed homogeneity and had five varieties except Dakh, which belongs to vinifera. It may be wrong introduction. Concord separates initially from all other varieties. Incidentally, Concord is a pure selection from V. labrusca, while varieties like Bangalore blue, Black Muscat, Catawba and Muzzafar Nagar in labrusca group may be the hybrids of labrusca x vinifera. The current study thus revealed that genetic relationship among grape cultivars could be assessed using ISSR markers.

ABSTRACT

DNA fingerprinting is increasingly being used for identification of varieties, quantification of similarity between varieties and study of genetic diversity available in the population.

This is all the more important in crops where morphological variability is less or one variety is known by different names or different varieties are known by same name.

DNA fingerprinting using RAPD method has been standardized for tapioca. Dellaporta method has been used for extraction of DNA and amplification was done following William’s method. This technique has been used for molecular characterisation of accessions and identification of duplicates in the germplasm maintained at Central Tuber Crops Research Institute, Thiruvananthapuram. This technology has been extended for DNA fingerprinting of released varieties and also some of the elite breeding lines.

Eleven varieties released from the institute were fingerprinted using a few primers, which showed high polymorphism in tapioca. One single primer gave distinct banding pattern for all the 11 varieties and it was capable of earmarking each variety.

Individual variety was finger printed for 20 different primers and the results were documented. This technique is being extended to promising land races as well. DNA fingerprinting will be useful for protecting Plant Breeders’ Right as well as Farmers’ Right in the new Patent Regime.

ABSTRACT

Hevea brasiliensis, the main source of natural rubber (NR) is commercially propagated through bud grafting. Since Hevea brasiliensis is a cross-pollinated tree crop, seeds obtained are highly heterozygous. Earlier, plantations were grown from unselected seeds. But due to poor yield and large tree - to - tree variations in growth and yield in such plantations bud grafting with desirable scions is now being adopted for commercial planting. Genetically divergent seedlings grown from open pollinated seeds are used as rootstocks to graft the selected scion. This can lead to stock - scion interactions. Large intraclonal variations observed in growth and yield of bud-grafted clones of Hevea are attributed to the genetic heterogeneity of the rootstocks. Monoclonal and polyclonal seed gardens have been established in Kanya Kumari District of Tamil Nadu for producing good quality seeds. Monoclonal seeds are collected from monoclonal seed gardens where only one clone is planted in a vast area without any interference from pollen grains from other clones. Polyclonal seeds are collected from polyclonal seed gardens where different clones are planted in an area and the seeds are fertilized by pollen grains from all the clones. It is a general assumption that seedlings grown from polyclonal seeds may be highly heterogeneous than seedlings grown from monoclonal seeds. The objective of the present study was to find out the reliability of this assumption by studying the genetic variations existing among the polyclonal and monoclonal seedlings. RAPD analysis of leaf samples from polyclonal and monoclonal viz, RRIM 600, PB 86 and GT1 seedlings was carried out using ten Operon arbitrary decamer primers that gave informative amplification. The results showed that there was no significant difference in the genetic variations among the polyclonal and monoclonal seedlings.

ABSTRACT

The study was conducted to fingerprint and to analyze genetic diversity among 20 genotypes. of Psidium guajava and two species P. friedrichsthalianum and P. cattleianum using random amplified polymorphic DNA. Genomic DNA was isolated using modified CTAB method and polymerase chain reaction was carried out using standard protocols. In all 41 primers were used, 39 of which amplified 376 alleles with 347 polymorphic alleles. All the primers discriminated between two and more genotypes. Primers produced 2-16 alleles. The size of amplified DNA alleles ranged from 0.12-2.2 kilobase pairs. Polymorphic index content value was found to be maximum for primer OPB-12 (0.916). In the dendrogram all the 22 genotypes were grouped into two major clusters. Cluster 1 comprised of Spear Acid, Apple Colour and P. friedrichsthalianum, while Cluster 2 constituted rest of the 19 genotypes. Thus, RAPD markers detected a high level of polymorphism and can be used for breeding of improved guava varieties.

ABSTRACT

An effort was made to characterize twelve ber genotypes using RAPD markers. Of the twenty random decamer primers tested, 17 generated polymorphic bands, while rest of the primers showed monomorphic bands. The primers that amplified all the 12 genotypes were OPC-20, OPD-1, OPD-3 and OPD-4. The size of amplified DNA fragments varied from 0.56-4.26 kilobase pair. In total, 109 bands were obtained, of which 85 bands were polymorphic, while 24 bands were monomorphic. For the cultivars tested between 2-9 bands were obtained for each primer with an average of 5.45 bands per primer. The highest number of bands (9) were generated by OPA-4 and OPD-3. With un-weighted group method using arithmetic mean (UPGMA) cluster analysis, the twelve ber genotypes fell into four major clusters. The pair wise dissimilarities of ber genotypes showed that genotypes G-9 and G-8 were close to each other. Maximum dissimilarity was observed between the genotypes G-8 and G-12.

ABSTRACT

The discovery of polymerase chain reaction method of amplification of DNA is an important milestone in molecular genetics and used for multiple purpose such as construction of linkage maps, marker saturation of specific genome regions, analysis of genetic diversity, molecular phylogeny and cultivar identifications (Williams et al; 1990, Demeke, Adams and Chibbar; 1992, Welsh and Maclelland; 1990;, Obara-Okeyo and Kako; 1998, Sawhoon Lin et al; 1998 and Grunger et al; 1998.). 15 species of three morphologically distinct groups of Orchids belonging to the subfamily Epidendroideae and tribe Dendroebieae and Cymbideae were studied using random amplified polymorphic DNA (RAPD) technique. Genetic variability and relation between these 3 genera and 15 species were estimated based on band sharing and cluster analysis. A total of 227 distinct major RAPD bands of which 97% were polymorphic were generated from 15 arbitrary primers. The number of bands generated per primer ranged from 3 (Primer A-10) to 22 (Primer K-10 and N-17) with a mean of 14.8 bands per primer. Out of 227 bands generated 222 bands (97.8%) where polymorphic while only 5 bands were monomorphic. The primer resolving power was found to range between 2.00 (prime A-10) and 13.38 (primer k-10) when all the species were studied were taken into account. The molecular analysis grouped all the species into 5 groups. The polymorphic patterns generated by RAPD profiles showed different degrees of genetic relationship among the species studied and the RAPD marker were found to be an useful tool for detecting genetic variation within the species of three important genera of Orchids.

ABSTRACT

Genetic variability was assessed among twenty five distinct drumstick (Moringa oleifera Lam.) landraces using PCR based random amplified polymorphic DNA (RAPD) markers. Genomic DNA extracted from tender leaves was used for RAPD analysis. Thirty five primers were screened and based on the number of bands three primers were selected. The primers produced 34 bands, of which 58 % (20 bands) were polymorphic. The data were analysed using NTSYS pc 2.1 software. The similarity matrix constructed using Jaccard’s coefficient method was subjected to cluster analysis using UPGMA (Unweighted Pair Group Method with Arithmetic Mean) and dendrogram was generated. The pair wise coefficient values in the genetic similarity matrix among the landraces varied between 0.28 and 1.00. The dendrogram based on the matrix separated the landraces with distinct morphological characters and it was noted that the cluster formation was not fully in agreement with the geographical location. The study showed the use of RAPD markers in detecting genetic variability present among the drumstick landraces studied.

ABSTRACT

There is a wide variability in the contents of the commercially important chemical compounds of Centella asiatica depending on the source / ecotypes of the plants. The glycosides found in Indian plants include brahmoside, brahminoside and minor amounts of asiaticosides, which vary in their relative contents depending on the ecotypes. An RAPD marker assisted study of ten accessions, collected from different geographical locations of Kerala, viz., Parumala (Kottayam District), Kottayam, Nagercoil (Tamil Nadu), Mananthala (Trivandrum District), Vlathankara (Trivandrum District), Ponmudi (High range, Trivandrum District), Angamaly (Ernakulam District), Punalur (Kollam district), Pattambi (Palakkad district) and Calicut, was conducted. DNA amplification of the accessions was studied using forty decamer primers, involving 43 cycles. Based on the number of bands four primers were selected. The least similarity coefficient of 0.71 was shown by the Pattambi accession, which formed a separate cluster with all other accessions. Nagercoil and Ponmudi accessions showed the highest similarity coefficient of 0.88 with each other.

ABSTRACT

In oil palm there are three fruit forms viz. dura, tenera and pisifera. The commercial planting material is tenera produced by crossing dura and pisifera (D X P). Dura has thick shell and less economic part, where as pisifera is an abortic, female sterile type and cannot be reproduced in the normal ways. When tenera is selfed, segregation takes place in the monogenic Mendelian ratio; 1 dura: 2 tenera: 1 pisifera. Since all these palm types are morphologically alike, they can be confirmed only after fruiting, and verifying the internal fruit morphology. Fruiting in pisifera is highly erratic and often prolonged to several years. Proper technique in identifying these palms has been puzzling the breeder all over. Hence, a shell thickness marker is very important for early identification of the oil palm varieties.

An attempt has been taken to screen PCR primers and select the probable primers linked to the shell thickness in the present study. ‘Bulk segregation analysis’ approach was adopted for the study and DNA isolation was carried out from 25 dura and 25 pisifera palms. All the palms were developed from same tenera x tenera crosses. DNA from all the 25 duras and 25 pisiferas were pooled separately. Two pooled DNA samples were subjected to RAPD analysis with 50 random primers using the standard RAPD protocol. The amplified samples were electrophoresed and documented.

Both the pooled samples showed same banding pattern with all the primers, except 10 primers showing differences. Since the genetic configuration of the pooled dura DNA was likely to be same as that of the pisifera pooled DNA, the primers showing difference in banding pattern were the putative primers linked to shell thickness. All the 10 primers would be used for amplification of individual dura and pisifera DNA for confirmation of shell thickness marker.

ABSTRACT

Of the several PCR techniques developed during the last two decades, random amplified polymorphic DNA (RAPD) offers a simple and economical means of genotype characterization. The information obtained through RAPD characterization is extensively used for the identification of genotypes, screening of duplicates, assessing genetic diversity and monitoring the genetic stability of conserved germplasm. The present study is a report on the DNA fingerprinting of P. nigrum and P. longum cultivars. Fourteen land races and three advanced cultivars of P. nigrum and eleven land races and one advanced cultivar of P.longum were used in the present study. Forty decamer primers from Operon Tech were screened using two representative genomic DNA samples of black pepper. Of these, 10 primers that yielded clear and dominant band patterns were selected for the final analysis of the 29 accessions. These generated 119 amplification products. The total number of markers per primer varied with respect to both P. nigrum and P. longum. Cultivar specific single bands were obtained for a few land races and accessions of both the Piper species.

ABSTRACT

Production of cardamom in India has been greatly affected by Cardamom mosaic virus (CdMV). The conventional breeding program to develop resistance is a lengthy process. An alternative approach is to develop transgenic cardamom through introduction and expression of viral sequences in the plant. The coat protein (CP) gene of all the CdMV isolates have been cloned in pGEMT vector and sequenced. Sequence comparison studies of the eight isolates of CdMV in their CP and 3’UTR showed that, Kursupara isolate is highly variable from the rest of the isolates (Jacob et al., 2003). Hence the present study was undertaken to introduce the Kursupara CP gene of CdMV into cardamom plants in order to develop pathogen-derived resistance in cardamom. The CP gene of the Kursupara isolate of the virus was amplified with and without the 3’untranslated region (3’UTR) from the viral clone. These PCR products were cloned into the pXcmkn12 vector and sub cloned in to a plant expression vector (pAHC17) at the BamHI site, under maize ubiquitin promoter. Work is in progress towards the biolistic transformation of cardamom with these constructs.

ABSTRACT

Zingiber officinale is a herbaceous perennial. The absence of seed set in ginger makes conventional breeding methods inapplicable. Genetic modification through biotechnological means is the only way for introducing novel genes into the cultivated types. Transient expression of the gus reporter gene was used in preliminary experiments. Agrobacteruim tumefaciens strains EHA105/p35SGUS Int. effective in expressing b- glucuronidase activity was used for standardizing the optimum conditions for effecting transformation, such as preculture of explants, bacterial dilution, infection time, co-cultivation period etc. In addition, effects of acetosyringone and explant wounding were evaluated using the same strain. Genetic transformation of bud and regenerated plantlets was confirmed by their ability to grow on MS medium containing kanamycin 100 mg l-1 + cefotaxime 300 mg l-1 by histochemical b-glucuronidase assays.

ABSTRACT

Coleus forskohlii Briq. is a threatened medicinal plant , susceptible to fungal disease. The regeneration of this plant has been achieved on MSo medium supplemented with 2 mg/l or 3 mg/l BAP and 0.2 mg/l 2,4-D for callus induction using leaf as explants. Multiple shoot production from the leaf-derived transformed callus of coleus has been standardized using the various concentration of NAA with 2 mg/l BAP. The combination of 2 mg/l BAP and 0.5 mg/l NAA was found to be best for multiple shoot production. Rooting was found to be best on MS medium supplemented with 0.7 mg/l NAA. Coleus forskohlii was transformed with glucanase-chitinase gene along with npt-II gene. The presence of npt-II genes in the leaves of putative transformants were confirmed by PCR analysis. SDS- PAGE analysis and glucanase assay revealed the over expression of glucanase enzyme in the transgenic plants. The transgenic coleus plants survived the infection caused by Fusarium chlamydosporium due to the accumulation of glucanase-chitinase enzyme, where as control plants were susceptible to the disease.

ABSTRACT

Fruit rot and die back caused by Colletotrichum capsici is the destructive disease in chillies. The potential of Pseudomonas fluorescens for the management of fruit rot of chillies was evaluated under greenhouse and field conditions. Among the various strains of P. fluorescens tested in vitro, the strain Pf1 significantly inhibtied the mycelial growth of C. capsici. Combined application of talc-based powder formulation of P. fluorescens to seed (10 g/kg seed) and foliage (1 kg/ha) effectively controlled the fruit rot disease. Early and high induction of various defense compounds were observed due to P. fluorescens treatment.

ABSTRACT

Chickpea is an important pulse crop of India and most suited to the use of rhizobia for its nitrogen requirement. Mesorhizobium ciceri which interact with the crop are poorly understood. Attempt has been made to select M. ciceri with several beneficial properties. Sixty four isolates of M. ciceri collected from the nodules of several chickpea varieties and mutant lines were screened for their growth properties on nitrogen free medium. Isolates MC59 and MC 18-7 showed normal growth and had ARA values at half level to that of Azotobacter. PCR amplification results suggested the presence of ACC deaminase gene sequence both in Azotobacter and M. ciceri. Invariably all isolates showed the presence of one plasmid in the range of 35 kb to 40 kb size.

ABSTRACT

Bacterial wilt caused by Ralstonia solanacearum is the major constraint for cultivation of tomato in Kerala. Biocontrol of plant pathogens is becoming an important component of integrated disease management. Among the various antagonists tested against R. solanacearum of tomato, fungi were more effective than bacterial and actinomycetes organisms. Among them, Trichoderma virens, T. viride (Ozhalapathy and Vellanikkara) and T. pseudokoningii were the effective ones, recording the maximum antagonism index (AI) value of 6000 under in vitro condition. They inhibited the pathogen completely by the mechanism of both lysis and overgrowth. In pot culture study, T. viride and T. pseudokoningii and commercial Pseudomonas fluorescens gave maximum protection against wilt incidence. Under field condition, T. viride (Ozh), T. pseudokoningii and P. aeruginosa showed the lowest wilt incidence of 50.0, 58.3 and 58.3 respectively against cent per cent incidence in the control plot.

ABSTRACT

Anursery experiment was conducted to study the effect of solarization, selected native antagonists viz., T. viride and T. longibrachiatum and the standard culture of T. harzianum for assesseing the growth enhancement and management of Phytophthora rot in black pepper nursery. The experiment was laid out at College of Horticulture with 20 different treatments and replicated thrice. The sprouting percentage of cuttings in different treatments was worked out at different intervals, which showed significant difference. In general, it was observed that the maximum sprouting percentage was noticed in treatments where solarized potting mixture and biocontrol agents were used. The population of soil microflora viz., fungi, bacteria and actinomycetes in different treatments were also estimated. The study indicated a fluctuation in the population of soil microbes in various treatments at different periods of observation. The observations on height and number of leaves of pepper cuttings in different treatments were recorded. It was noticed that cuttings raised in solarized potting mixture incorporated with native antagonists, especially T. viride, exerted a significant effect in increasing the height of cuttings. With regard to total number of leaves, it was also observed that addition of native antagonists in solarized potting mixture had a positive effect in increasing the leaf production. Thus, the effect of solarization enhanced the growth parameters in crop plants by making available the required nutrients. The increased growth response of plants by soil application of Trichoderma spp. may be due to the production of growth promoting substances by the antagonists. Thus, the nursery experiment revealed that, in general, soil solarization and incorporation of antagonists had a favourable effect in promoting the growth of pepper plants besides checking the Phytophthora rot in black pepper nursery.

ABSTRACT

Banana is one of the most accepted and versatile fruit crops across the globe and in Kerala, it is the most important economically profitable fruit crop grown, mainly by small and marginal farmers, providing a vital source of income. However, the productivity of this crop is very much reduced due to various diseases of which rhizome rot disease is an important one. In recent years, this disease has become a serious problem to the commercial cultivation of banana in southern states of India like Kerala, Karnataka, and Tamil Nadu.In Kerala the disease incidence is found to be nearly 30% and it will soon become cent percent if unnoticed since the disease is more seen in banana cultivated in paddy fields, and the area under the cultivation of banana in paddy fields in Kerala is rapidly increasing. The disease is caused by a gram negative bacterium, Erwinia carotovora. Developing an integrated management package involving biocontrol methods is the only remedy for managing the disease within the financial limits of the marginal farmers. With this intension a pot culture experiment was conducted to study the inhibitory effect of different biocontrol agents and botanicals in the incidence of the disease after testing their efficacy under in vitro cond itions. The results revealed that the biocont rol agent Pseudomonas flourescens (commercial preparation @ 7g /plant) was found to effective in managing the disease. The co- efficient of infection was found to be13.9% as against the control pot where it was 56.24%. With regard to the growth parameters also, the treatment with this biocontrol agent gave superior results. Thus it was proved that Pseudomonas flourescens (commercial preparation @ 7g /plant) could be successfully utilized in the integrated disease management making it cost effective.

ABSTRACT

To study the antagonistic potential of rhizobacteria against the soil borne pathogen Rhizoctonia solani, soil bacteria were isolated from the rice fields of Agricultural Research Station, Mannuthy and screened against R. solani. Out of the 22 rhizosphere bacteria, 10 were found to be antagonistic to R. solani. Seven belonged to the genera Bacillus, Pseudomonas, Clostridium and Sporosarcina and the rest three being unidentified. The bacterial isolates viz., 2B, 4B, 19B (Bacillus sp.), 28B and 10B (Sporosarcina sp.) showed increase in inhibition on extending the period of incubation. Maximum inhibition was expressed by 2B on the third day of inoculation followed by 4B, 10B (Sporosarcina sp.), 7B (Bacillus sp.) and Pseudomonas fluorescens. The bacterial isolate 4B and 7B (Bacillus sp.) and 10B (Sporosarcina sp.) completely prevented the sclerotial production of R. solani whereas 1B (Clostridium sp.), 2B, 19B (Bacillus sp.) and P. fluorescens delayed the sclerotial production. Pot culture studies also confirmed the superiority of these rhizobacteria in controlling the infection by R. solani. The potentiality of these rhizobacterial antagonists can be exploited for the management of soil borne pathogens like R. solani.

ABSTRACT

Phytophthora pod rot (PPR) incited by Phytophthora palmivora is the most serious disease of cocoa, inflicting heavy crop losses. Since, antagonistic microbes are useful in ecofriendly management of plant diseases, the present study was undertaken to harness the potential of antagonistic epiphytic microflora isolated from cocoa pods for the management of PPR of cocoa. A quantitative estimation of the epiphytic microflora from pods collected from different locations of cocoa gardens of Thrissur district revealed more abundance of bacteria followed by fungi, actinomycetes and fluorescent pseudomonads. The in vitro antagonistic effect of 16 isolates of fungi, 22 isolates of bacteria, five isolates of actinomycetes and two isolates of fluorescent pseudomonads from pod surface against P. palmivora was carried out in comparison with standard cultures of Trichoderma harzianum and Pseudomonas fluorescens. The study revealed that all the epiphytic fungal and bacterial isolates including standard cultures of T. harzianum and P. fluorescens were antagonistic to P. palmivora in varying degrees. Based on the in vitro screening seven promising epiphytic fungal isolates and five bacterial isolates along with standard cultures of T. harzianum and P. fluorescens were evaluated for their efficiency in reducing the infection by P. palmivora on detached pods. The pathogen was inoculated on the pods one hour after application of antagonists. Observations taken 10 days after inoculation of the pathogen revealed that one isolate of T. viride and two isolates of P. fluorescens obtained from pod surface exerted more than 40 per cent efficiency over control in reducing the infection. The standard cultures of fungal and bacterial antagonists recorded 33-35 per cent efficiency. Hence, these efficient epiphytic and standard cultures could be utilized for the management of PPR of cocoa.

ABSTRACT

Interaction of cationic dye acridine orange with lipopolysaccharide (LPS) isolated from Rhizobium strains specific (IC59) and non-specific (TAL1000) to chickpea (Cicer arietinum.L L.) has been investigated by spectrophotometric measurements. The strain specific (IC59) lipopolysaccharide induced decrease in absorbance of the α-band of acridine orange at 490 nm and finally upon further addition of LPS /Dye ratio in the range of 30~60 giving rise to α-polymeric metachromatic band at 660 nm. In contrast the LPS from non-specific strain (TAL1000) induces a decrease in absorbance at the α-band till LPS / Dye ratios are 0~50. This suggest that the anionic changes of strain specific LPS is different from non-specific strain enabling formation of large acridine orange aggregate on the surface of specific strain.

ABSTRACT

An in vitro evaluation was carried out to find out the efficiency of bacterial and fungal antagonists in checking the growth of pathogens of Kacholam. Out of the two methods tried to find out the effectiveness of Pseudomonas fluorescens against the two isolates of Ralstonia solanacearum, cross streaking produced lysis at the juncture and point inoculation produced clear inhibition zones. Among the two fungal antagonists tested Trichoderma viride was more efficient than Aspergillus niger because of its faster growth over the pathogen. However, both the antagonists showed complete overgrowth and dense sporulation on the area where the pathogen was streaked. To find out the efficacy of Pseudomonas fluorescens against leaf spot pathogens like Colletotrichum gloeosporioides and C. capsici, streaking on both sides yielded more than 50 per cent reduction in growth of both the fungal pathogens. The fungal antagonist T. viride showed a faster growth over pathogens than A. niger eventhough both recorded an antagonism index of 1500. Dense sporulation was seen over the pathogens in case of T. viride. The ability of fungal antagonists to produce volatiles and their effect on fungal pathogens were also assessed. It was noticed that the volatiles produced by T. viride was more effective than that of A. niger. Even though the extent of inhibition was less compared to direct action, this could also be one of the mechanisms of action of both the antagonists. The study revealed that all the three antagonists were effective against both bacterial and fungal pathogens and they could be utilized under field conditions.

ABSTRACT

Soil samples from pepper growing tracts of six districts of Kerala viz., Ernakulam, Idukki, Kollam, Kottayam, Thrissur and Pathanamthitta were assessed for total microbial population. Thirty two fungi, 17 bacteria and three actinomycetes were isolated and studied for their antagonistic potential against the foot rot pathogen, Phytophthora capsici. All the 32 fungal isolates were found antagonistic to the pathogen and majority of them belonged to the genera Trichoderma, Aspergillus, Penicillium, Fusarium, Pythium, Cunninghamella and Rhizopus. Among these maximum inhibition was recorded by Trichoderma spp. which included T. pseudokoningii, T. longibrachiatum, T. polysporum and T. harzianum. The laboratory studies were followed by field trials laid out in farmers’ fields (newly planted pepper gardens) in six districts of Kerala. Effect of biocontrol agents in wilt incidence revealed that the two-time treatment of combined application of Trichoderma local isolate and potassium phosphate was superior in checking the foot rot incidence. The treatment, Trichoderma local isolate + Bordeaux mixture applied twice came in the second position. Data on biometric observations revealed a significant increase in the number of laterals in plots treated with Trichoderma local antagonist and potassium phosphate as compared to plots treated with Bordeaux mixture and copper oxychloride. Results of quality analysis of berries revealed that oleoresin content ranged from 6.98 - 11.84 per cent and piperine content from 3.61 - 5.92 per cent and the quality remain unchanged due to various treatments. The study has provided an ‘eco and health friendly’ biological control for the management of Phytophthora foot rot, the most devastating disease of pepper.

ABSTRACT

Trichoderma spp. are important group of fungi which are mycoparasitic on several plant pathogenic fungi. Trichoderma spp. are, therefore, used as commercial biofungicides. Genetic manipulation through induced mutagenesis and molecular cloning are two important tools in improving the biocontrol potential of Trichoderma spp. In the present study, attempts were made to induce genetic variability in Trichoderma virens using UV- induced mutagenesis. In the process, a simple protocol was developed for obtaining high frequency mutations in Trichoderma virens. Using a UV-crosslinker, four stable mutants of T. virens have been developed, which are distinctly different from the wild type in appearance and in antagonism against Rhizoctonia solani and Sclerotium rolfsii. One of the mutants, designated as TI is very slow in growth, but sporulates densely, and retained its mycoparasitic potential against R. solani. Though all the mutants were able to antagonize R. solani, all of them were overgrown by the test pathogen S. rolfsii. These mutants could be used to identify genes involved in growth and conidiation in T. virens.

ABSTRACT

Detection of disease tolerance with enhanced defense mechanism is a practical approach in crop variety improvement programme. Toxins being responsible for pathogenicity and virulence of the fungi, regenerating plants from toxin treated calli is an effective and easy approach. The response of tomato calli to the crude toxins of the foliar pathogens viz., Alternaria solani and Septoria lycopersici was studied and the changes in phenol metabolism due to toxin treatment were analysed. Crude toxins of A. solani and S. lycopersici extracted under optimum conditions were serially diluted and tomato calli were treated with different dilutions of the toxins to find out the optimum dilution at which minimum survival percentage was obtained, based on a 1-4 score. Minimum score of 1 was obtained at 1:10 dilution for A. solani and at 1:20 for S. lycopersici.

The calli of resistant (LE-625) and susceptible (CO-3) tomato varieties were treated with desired dilutions of the toxins of A. solani and S. lycopersici. Total phenolics and ortho- dihydroxy (OD) phenolics were estimated at 24 h interval to study the extent of necrosis on resistant and susceptible calli due to toxin treatment. The total and OD-phenol contents of calli of susceptible cultivar (CO-3) progressively decreased with increase in time interval consequent to the treatment of toxins of A. solani and S. lycopersici. In the resistant calli of LE-625, an initial reduction of total phenol and OD-phenol content was observed following the application of the toxins of A. solani and S. lycopersici at 24 hours after treatment. Later with lapse of time, the total phenol content and OD-phenol contents progressively increased reaching a maximum at 120 h after treatment. The results clearly indicated the enhancement of biochemical defense in the resistant calli and a fall in defense mechanism in the susceptible calli due to toxin treatment. Such techniques are useful in the preliminary screening of resistant genotypes in crops like tomato.

ABSTRACT

Apot culture experiment was conducted on tomato with cadmium and lead to identify the selective retention sites of the metals. For this a completely randomized design with five treatments and four replications were laid out at the College of Horticulture, Vellanikkara. The different levels of treatment ranged from 0.5 to 2.0 mg kg -1 soil. Cadmium and lead were directly supplied as a water-soluble source through cadmium chloride and lead nitrate respectively. In tomato the growth and fruiting was permitted only at lower levels of cadmium application. At 1.5 mg kg-1 soil, fruiting failed. While at 2.0 mg kg-1 soil, the very establishment of plant was totally affected. At higher levels of application, cadmium preferred to get accumulated in roots while on the contrary at lower levels, cadmium uptake increased in shoots than in roots with the least content of the metal in fruits. However, in the case of lead, all levels of application in soil permitted growth and fruiting. With increase in rate of lead application, significant selective retention was observed in roots (1.48-6.69 ppm), shoot (0.29-1.62 ppm) and fruits (0.39-1.45 ppm). On comparison of retention sites of lead in tomato, it could be seen that fruits maintained the maximum lead uptake (637.2-2933.0 mg pot-1). Hence, the consumption of such tomato fruits contaminated with heavy metals may result in kidney damage, lack of memory, dissolution of phosphorus in the bones etc.

ABSTRACT

The potato is one of the most important food crops both in developed as well as in developing countries. Developing countries today produce 37 per cent of world’s output of potatoes. Potato is an important food crop in India. Both area under potato cultivation and production has increased manifolds during past decades. The efforts are being made to improve potato quality and its post harvest life as well.

An experiment was conducted to isolate mitochondria from potato tubers and succinate dehydrogenase (SDH) assay and protein profiling were performed in the tissue. Three varieties namely, Kufri Bahar, Kufri Lauvkar and Kufri Jyoti were taken into consideration for the present investigation. Kufri Bahar showed the minimum values for SDH activity and Kufri Jyoti the maximum SDH activity. On the basis of SDH activity, the mitochondria in Kufri Jyoti were seemed to be more viable, functional and coupled as compared to Kufri Bahar and Kufri Lauvkar. This finding also suggested that the respiratory degradation of starch in Kufri Jyoti was higher as compared to Kufri Bahar and Kufri Lauvkar. Thus these result showed that the shelf life of Kufri Jyoti was less as compared to Kufri Bahar and Kufri Lauvkar. Protein profiling performed by SDS-PAGE was found to be similar in all the potato tubers.

ABSTRACT

Astudy was undertaken at Department of Soil Science & Agrl. Chemistry, College of Horticulture, Vellanikkara to standardize different amelioration techniques to prepare enriched coirpith compost. Twelve treatments were tried using different combinations of coirpith, Pleurotus spp., Schizophyllus spp., urea, rock phosphate, cowdung slurry, mushroom waste, goat manure, glyricidia and water hyacinth. The results of the various enrichment techniques revealed that the temperature in the compost in general, increased to a peak value of 47oC on the 22nd day of composting and later decreased to a stabilized value. The observed temperature of 40-50 °C found during the thermophilic stage is essential for the rapid degradation of lignocellulose, as the thermophilic microfungi and actinomycetes involved in this process thrive at that temperature. Though the pH show a hike at the initial stage of composting, it decreased and stabilized at the later stage of composting which is conducive for growth and proliferation of microbes. The treatment coirpith with Pleurotus spp., glyricidia +20% cowdung slurry and goat manure was found to be ideal for compost preparation.

INTRODUCTION

It can be added that physiological stress as well as the physical offences contribute as primary factor for disease occurrence and fish mortality. Many parasitic diseases due to fluctuation in water quality leads to deplition of stock, and some times total stock will go eg. yellow grub disease.

EFFECT OF TEMPERATURE ON PARASITES

Heterophyid Trematode

Cyprinodon variegatus, an estuarine fish, is heavily parasitized in the bulbus arteriosus by the heterophyid trematode Ascocotyle pachycystis. Parasitized fish ventricles were hypertrophied due to mechanical blockage of normal blood flow by metacercariae in the bulbus Swimming performance generally was reduced by the presence of parasites, which had their most significant negative effect at cold temperatures and low dissolved oxygen level ( Felicia C. Coleman , 1993)

Soil consistency is a term used to designate the manifestation of different physical forces acting within the soil at various moisture levels. The consistency limits, also known as ‘Atterberg Limits’ (Atterberg, 1911; 12) are defined by the water content of the soil to create specified degree of consistency. These limits are – (i) Liquid limit or upper plastic limit, (ii) Plastic limit or lower plastic limit and (iii) Sticky limit.

7.1. Determination of Liquid Limit or Upper Plastic Limit

Equipments and Materials

Liquid limit device (Casagrande, 1932) and accessories, spatula, dish, oven, moisture box, balance, desiccator

8.1. Law of Mass Action

Gulberg and Waage, the two Norwegian chemists in the year 1864 stated the law of mass action in this form: ‘The velocity of any chemical reaction at any instant at a given temperature is proportional to the active mass of each of the reactants at that instant present in the system, the active mass in a homogeneous system is defined as the number of gram molecule of the substance present per unit volume i.e., the molar volume’.

Mathematical Formulation of the Law of Mass Action

Let us take a simple case of a reversible reaction at constant temperature represented by the equation:

19.1. Plant Available Fraction of Nickel, Cadmium, Lead and Chromium

The DTPA method was originally developed to extract Mn, Cu, Fe and Zn from slightly acidic to alkaline soils (Lindsay and Norvell, 1978), but in some cases it can be used for other metals also such as Nickel (Ni), Cadmium (Cd), Lead (Pb) and Chromium (Cr). Among them Ni is considered as an essential micronutrient. The DTPA is used to extract soil metals by forming chelates with free metals in solution, which lowers their ionic activities so that additional quantities of metal are released from the soil until equilibrium is attained. Triehanolamine (TEA) is used to buffer the extracting solution at pH 7.3 in an attempt to optimize the extraction of various metals. Calcium chloride is included in the extracting solution to minimize dissolution of CaCO₃.

9.0. Introduction

Enzymes are organic biocatalysts which initiate and control biological reactions. A catalyst is an agent affecting the velocity of a chemical reaction without appearing among the final products of the reaction. Unlike general catalysts, enzymes are specific in nature and function at a temperature of approximately 37^o C and pH close to neutrality. All enzymes are proteins but all proteins are not enzymes. These are distributed among the cell and tissues of plants and animals. Use of malted barley in brewing, yeast in the production of alcoholic beverages and wrapping of meat in the bruised leaves of papaya tree for tenderizing meat are techniques that have been used for centuries. In bread and cheese making also, enzymes have been exploited from generation to generation. Thus, enzymes have been used without knowing the nature of enzyme as catalysts and reactions involved. However, it is only recently that nature and action of enzyme is known and its importance in food industry is realized.

Sprayer is a machine to apply fluids in the form of droplets. Sprayer is used for the following purpose.

• Application of herbicides to remove weeds.
• Application of fungicides to minimize fungus diseases.
• Application of insecticides to control insect pests.
• Application of micro nutrients on the plants.

The factors affecting sustainability of agriculture under small farm production system in coastal ecosystem of Odisha was studied to ascertain the status of ecological factors and suggest means and ways to improve the situation. The response of the sample farmers and the findings of the study together led to suggest the following measures for up-gradation of ecosystem of the coastal area leading to sustainability of agriculture. Like other states, Odisha is also facing with problems of sustainability of agriculture. Our sample districts namely Puri, Khurda, Ganjam and Balasore which are situated in coastal eco-system of the state has different problems concerning to natural resources like soil, water, forest and animal wealth, etc.

The suggestions to improve the sustainability status of agriculture have been viewed from two important angles. One is adoption of technological measures to preserve natural resources and other is the policy and extension approach to educate people about the necessity of taking such measures for sustainability of agriculture and improve upon.