eChapter Name: Molecular and Transgenic Breeding
9789389130812
eBook Name: BREEDING AND BIOTECHNOLOGY OF FLOWERS: SET OF 2 VOLS. (SET PRICE)
by Anil K. Singh, Dr. A.K. Singh
MOLECULAR BREEDING
Molecular breeding is the application of molecular biology tools, often in plant breeding.
Genetic markers
Genetic marker is defined as a gene whose phenotypic expression is usually easily discerned, used to identify an individual or a cell that carries it, or as a probe to mark a nucleus, chromosomes or locus (King and Stansfield, 1990). Three broad classes of genetic markers are morphological markers, biochemical markers and DNA or molecular markers.
(1) Morphological markers
Morphological markers are based on the visually assessable traits viz., morphological and agronomic traits. However, they are limited in number.
Features of morphological markers
i.They are easy to identify, there is no need of any complex analysis. Trait of interest can be identified visually.
ii.Morphological markers are inherited qualitatively or quantitatively.
iii.Frequency of availability of morphological markers is less in number i.e., morphological markers may not be available for all the traits of interest.
iv.They are influenced by environment.
v.Since they are influenced by environment, they are unstable in inheritance.
vi.They are stage specific i.e., a particular marker will be useful to identify in a particular stage of plant and not any stage of the plant.
vii.They are influenced by genotype and developmental stages of the plant.
Besides drawbacks, the morphological markers are useful to the plant breeders for the selection purpose in certain situation.