ABSTRACT
Kale is known for its exceptional nourishing and functional benefits to human body. However, it is an understudied species from genomic as well as agronomic aspects. It is important to characterize niche kale germplasms around the world to systematically conserve and utilize its genetic variability, especially for commercial traits in the interest of growers, consumers and industry. With this view, genomic and phenotypic characterizations of 62 Kashmiri kale accessions including popular landraces were done to estimate and partition genetic diversity, understand trait relationships, develop population structure and divulge marker-trait associations of economic significance. Sixty-six cross species microsatellite (SSR) markers within Brassica genus amplified 269 alleles in the germplasm. Their polymorphic information content (PIC) ranged from 0.00078 to 0.953 with an average of 0.407. The population structure analysis and neighbour joining tree clustering categorized the germplasm into three sub-populations. AMOVA revealed more within-population variance (67.73 %) than among-populations (32.27 %) variance. The principal component analysis (PCA) involving 24 agronomical traits revealed seven PCs (PC1 to PC7) having Eigen values more than 1, which explained a cumulative variation of 69.21 %. Association mapping with respect to these 24 agronomical traits using mixed linear model and general linear model revealed six overlapping significant marker-trait relationships with five being significant at probability value of 0.001/0.0001. The highly significant associations of two SSRs with economically important traits (siliqua length and seed weight) significantly correlated/related with leaf yield and seed yield were revealed for their possible utilization in marker assisted breeding for higher leaf and seed yields.
ABSTRACT
BACKGROUND: Capsaicin and its analogues known as capsaicinoids are the principal sources of pungency in Capsicum spp. In this study, characterization of North-West Himalayan chilli germplasm and commercial landraces of different Indian states known for different pungency-color combinations was done based on capsaicin concentration. Moreover, molecular variation in pungency among high, medium and mild/not pungent Capsicum spp., especially those adapted to North-West Himalayas were elucidated. METHODS AND RESULTS: Forty-nine genotypes of chilli comprising breeding lines of Kashmiri origin, commercial landraces of Southern Indian origin and one of the world's hottest chilli Bhut Jolokia from Nagaland state of India were used as an experimental material. Wide variation in capsaicin content was observed among the genotypes, wherein, Bhut Jolokia (Capsicum chinense) expressed the highest capsaicin content (10,500.75 µg/g). Further, molecular analysis of PunI gene was done for discovering SNPs responsible for variations in pungency. In the non-pungent Nishat-1 (Capsicum annuum var. grossum), the 650 bp DNA fragment was not amplified due to 2.5 kb deletion spanning the putative promoter and first exon of AT3. The amplified DNA product for high and medium pungent was sequencing. Sequence alignment among revealed SNPs which were further observed responsible for variations in amino acid sequence and protein structure. CONCLUSION: The observed variation in protein structure might be responsible for high capsaicin production in one genotype as compared to the other and hence the protein conformation determines its interaction with the substrate.
