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The present study was undertaken to investigate the inheritance of resistance against two variants of Fusarium wilt (Variant 1 and Variant 2), using highly resistant (ICP8863) and susceptible (Type 7) pigeonpea genotypes. In order to develop F2 mapping population from the cross Type 7 x ICP8863, homogeneity and true hybridity testing was carried out using molecular markers (OPP-17, CCB-10, PPMC-1, PPMC-2, and PPMC-3). Phenotyping of mapping population was carried against two variants in the pots inoculated with 5% of inoculum (w/w) under green house conditions. Chi-square test based on phenotypic data revealed that the resistance was governed by a single recessive gene against variant 1 and two recessive genes against variant 2 in ICP8863. These results will be helpful in developing appropriate mapping and resistance breeding strategies against these two variants of Fusarium wilt in pigeonpea. [ABSTRACT FROM AUTHOR]

Thirty two pathogenic isolates of Fusarium udum from different pigeonpea growing areas in India were studied for pathogenic and molecular variability. Pathogenic variability was tested on 12 pigeonpea differential genotypes, which revealed prevalence of five variants in F. udum. The amount of genetic variation was evaluated by Polymerase Chain Reaction (PCR) amplification with 20 random amplified polymorphic DNA (RAPD) markers and nine microsatellite markers. All amplifications revealed scorable polymorphisms among the isolates, and a total of 137 polymorphic fragments were scored for the RAPD markers and 16 alleles for the simple sequence repeat (SSR) markers. RAPD primers showed 86% polymorphism. Genetic similarity was calculated using Jaccard's similarity coefficient and cluster analysis was used to generate a dendrogram showing relationships between them. Isolates could be grouped into three subpopulations based on molecular analysis. Results indicated that there is high genetic variability among a subpopulation of F. udum as identified by RAPD and SSR markers and pathogenicity on differential genotypes. [ABSTRACT FROM PUBLISHER]