Genetic Characterization of Recently Developed Germplasm and Validation of SSR Markers Linked to Fusarium Wilt and Pigeonpea Sterility Mosaic Disease in Pigeonpea [Cajanus cajan (L.) Millsp.]

Background: Pigeonpea is an important grain legume crop and a source of vegetarian protein. To meet the growing food demand, there is a pressing need to develop high-yielding disease-resistant varieties of pigeonpea. Hence, the present study was conducted to characterize the recently developed genetic material for yield and yield-attributing traits, identify the resistant sources and validate the SSR markers linked to fusarium wilt (FW) and sterility mosaic disease (SMD) resistance in pigeonpea. Methods: Pigeonpea genotypes were evaluated in two environments for yield and yield-related traits to assess the genetic variability parameters. The genotypes were phenotypically screened for their response to fusarium wilt and pigeonpea sterility mosaic disease under controlled conditions. Result: High PCV, GCV, heritability and genetic advance as per cent of mean values were obtained for the traits number of primary branches plant-1, number of secondary branches plant-1, number of pods plant-1, pod bearing length and seed yield plant-1 in both environments. The diversity analysis using k-means clustering grouped the genotypes into nine clusters with high inter-cluster distance between clusters I and VIII indicating high genetic diversity between the lines present in these two clusters. The six genotypes (ICPL 15023, ICPL 15063, ICPL 19467, ICPL 19482, ICPL 19489 and ICPL 19499) showed a combined resistance response. The validation of reported linked SSR markers was done using 52 resistant and susceptible germplasm lines. Four markers, AHSSR 50, AHSSR 34, AHSSR 20 and CcM0588 and seven markers viz., ASSR 23, ASSR 229, ASSR 363, HASSR 18, HASSR 121, HASSR 128 and CcGM 03681, were able to differentiate resistant and susceptible genotypes for SMD and FW, respectively. Subsequently, one marker (AHSSR 20) for SMD and four markers (ASSR 229, HASSR 121, HASSR 128, CcGM 03681) for FW were found significantly associated with disease resistance based on single marker analysis based on t-test. The identified potential genotypes can be used as a source of resistance to SMD and FW or directly released for commercial cultivation after extensive testing.