Mapping of Quantitative Trait Loci for Bruchid Resistance in Blackgram [Vigna mungo (L.) Hepper]

Background: Blackgram is one of the most important pulse crops. The post-harvest loss in blackgram is due to Callosobruchus maculatus where, the loss can go upto 100 per cent through secondary infestation. Development of cultivar with bruchid resistance can be cost-effective, durable and eco-friendly approach. The present study was conducted to identify markers linked to bruchid resistance in blackgram using the mapping population (RILs) developed from the cross between VBN(Bg) 5 (bruchid susceptible) and Vigna mungo var. silvestris 22/10 (bruchid resistant). Methods: A total of 191 RILs were subjected to bruchid screening and the traits viz., days to first adult emergence, mean developmental period, seed damage percent and growth index was observed. To analyse polymorphism between the parents, 343 SSR markers were screened and only 49 (14.29%) SSR markers showed polymorphism between the parents. Bulk segregant analysis (BSA) was done using resistant bulk and susceptible bulk along with parents using polymorphic markers. A total of eight SSR markers were identified as polymorphic in BSA. QTLs were mapped for seed damage per cent and growth index. The flanking markers for the QTLs identified for seed damage per cent and growth index was CEDG088 and CEDG118. Seed damage percent and growth index shared same position. The above markers were validated using four each of resistant and susceptible genotypes of blackgram. Result: The marker CEDG118 clearly distinguished the resistant and susceptible genotypes. The closely linked SSR marker CEDG118 could be used to screen the germplasm and segregating materials in order to identify bruchid resistant genotypes in blackgram.