eChapter Name: PCR-Based Markers in Crop Variety Identification
9789372197969
eBook Name: RECENT ADVANCES IN CROP VARIETY IDENTIFICATION USING DNA TECHNOLOGY
Introduction
In recent years crop yields have increased significantly due the development of new varieties and cultivars. Certain characteristics, like disease resistance, plant height, yield potential, and maturity period, set one variety of a cultivated crop species apart from other variations of the same species. A key element of contemporary agriculture is the precise identification of crop types, which is essential for plant breeding, seed certification, and the defence of intellectual property rights. The increasing demand for improved crop varieties with increased yield, disease resistance, and environmental adaptability has demanded the development of accurate methods for differentiating cultivars (Hannah, 2024). Traditional techniques of variety identification rely on morphological, biochemical, and agronomic features, which can be altered by environmental conditions and are generally time-consuming and labour-intensive. Various molecular marker systems have been developed to differentiate plant varieties and species of agricultural and horticultural significance. For effective seed quality control programs and the preservation of breeders’ rights, it is essential to define the identity, genetic purity, and stability of plant varieties. According to Yuan et al., (2022), precise variety identification is essential for determining genetic purity, analyzing genetic diversity, improving germplasm for better agronomic qualities, and getting rid of duplicate accessions.
For plant protection and production systems of Intellectual Property Rights (IPR) and Plant Biodiversity Register (PBR), accurate cultivar identification is crucial. According to Ghosh et al. (2001), molecular marker approaches are pertinent to PBR registration in the following ways. (1) In order to establish a set of comparison cultivars, genetic distance analysis between the candidate cultivar and the current pool of cultivars is performed. (2) The contribution of the comparison cultivar to PBR registration is then determined, and (3) the use of DNA markers to identify cultivars in cases where PBR infringement is alleged is investigated. The capacity of PCR-based markers to amplify particular DNA sequences has made them popular among molecular marker techniques, enabling accurate identification of genetic variations. Although conventional approaches are still employed for Plant Variety Protection (PVP), molecular techniques can be useful adjuncts that increase the effectiveness of accomplishing this goal. During variety certification, additional information from isozyme analysis, RFLP, SSR, SNP, or other genetic fingerprinting methods can be added to cultivar descriptions. Plant varieties can be legally protected on the basis of precise and unique molecular marker data. Crops with little morphological variation benefit greatly from molecular methods. To guarantee complete protection of cultivars, it is ideal to use both botanical and molecular evaluations (Yu and Chung, 2021). Amplified Fragment Length Polymorphism (AFLP), Random Amplified Polymorphic DNA (RAPD), Simple Sequence Repeat (SSR), and Inter Simple Sequence Repeat (ISSR) are the four main PCR-based markers used in crop variety identification that are the subject of this chapter. In plant genetics, each of these marker systems has special qualities, benefits, and uses. While AFLP markers give high resolution and genome-wide coverage, RAPD markers offer a rapid and economical method of polymorphism detection. Due to their high polymorphism and co-dominant inheritance, SSR markers—also referred to as microsatellites—are perfect for genetic mapping