Molecular characterization of advanced breeding lines of lowland rice and their evaluation for grain quality traits
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Date
2018
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College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University, Imphal
Abstract
Every third person on earth consumes rice every day in one form or another, hence it is called as the staple food. India shares the largest area under rice cultivation but stands as the second largest producer of rice, next to china. The demand for rice will increase with population growth, whereby the decline in milled rice production is challenging. This necessitates the need for diverse and highly productive breeding lines combined with good quality traits for future breeding programs or for multiplication and better returns for farmers. Hence the present investigation was undertaken to characterize twenty two advanced breeding lines of lowland rice derived from nine pedigrees to ascertain genetic relationship and diversity among the genotypes using a set of thirty SSR markers and twenty four random SNPs with ten gene specific SNPs followed by evaluation for fifteen grain quality traits. Population structure analysis using STRUCTURE software revealed the ancestry shared among the breeding lines. Sixteen breeding lines were catergorized as admixtures as they showed less than 85% of the estimated ancestry. These admixtures or breeding lines having differences in ancestry share could be preferred for further breeding programs or multiplication. Divergence analysis showed that maximum Euclidean distance was observed between CAUS116 and CAUS117 followed by CAUS116 and CAUS120, whereas, the minimum Euclidean distance was observed between CAUS110 and CAUS111. Ward’s hierarchical clustering approach grouped genotypes into two major clusters that were further subdivided into sub groups. Maximum variation among the genotypes was observed for amylose content, seed breadth and gelatinization temperature which classified the breeding lines into three classes while the traits such as grain length:breadth ratio, linear elongation and protein content categorized the breeding lines into two classes, respective to the values recorded under each trait. Highly significant variation was observed for all the traits evaluated. Amylose content ranged from 18% to 27% among the breeding lines while the protein content ranged from 11% to 5.5%. CAUS122 and CAUS107 were found to contain highest amount of iron and zinc. Highest GCV was recorded for amylose content suggesting selection based on the trait would be effective. Similarly, among physical traits highest GCV was recorded for grain length breadth ratio. The heritability recorded for the quality traits was high indicating that selection for quality traits is effective. Therefore, based on these results the diverse breeding lines having higher yield with better grain quality could be considered for future breeding methods as parents or can be released as varieties after multi-locational evaluation.