Molecular diversity and trait association analysis in different wheat genotypes for yellow rust resistance.

Yellow rust, caused by Puccinia striiformis Westend. f. sp. tritici Erikss. (Pst), is one of the most damaging wheat diseases because of their widespread distribution and ability to produce new races that can attack cultivars that were previously resistant. In this study characterization of 48 wheat genotypes was done using 51 primers comprised of stripe rust gene-specific markers and found that WH730 and WH1142 possess the highest number of rust resistant genes while WH1263 bears the lowest Yr genes. These identified resistant Yr genes were exhibited at different frequencies. The resistant genes like, Yr6, Yr18, Yr46, Yr53 and Yr61 were absent in all the 48 studied wheat genotypes. Yr35 and Yr51 had the highest frequency (95.3 and 91.6%, respectively), while Yr16 related to xwmc177 and xwmc18 had lower frequencies (8.0 and 10.4%, respectively). Genetic diversity analysis using 61 molecular markers, and population structure analysis grouped the population into three clusters. Association study of morph-physiological traits showed that the marker xgdm160 was strongly associated with two traits i.e. days to anthesis and days to heading at P value 0.0031 and 0.0048 (P < 0.01), respectively, and showed the highest phenotypic variance (R²). These assessed markers might help develop novel genotypes with numerous genes of resistance against yellow rust races in wheat genotypes by marker-assisted pyramiding. [ABSTRACT FROM AUTHOR]