Identification of stable resistant wild pigeonpea donors to multiple predominant bruchid species in India.

Identifying stable-resistant sources offers an eco-friendly and sustainable insect management strategy. Sixty-eight wild pigeonpea accessions were systematically screened against three predominant bruchid species (Callosobruchus analis, C. chinensis, C. maculatus) using a high-throughput screening pipeline at Kanpur, India, from 2021 to 2024. Resistance classification was based on seed damage and susceptibility index. Four Rhyncosia bracteata accessions consistently exhibited convergent and complete resistance across species, while few C. scarabaeoides accessions were resistant to C. chinensis and C. maculatus but moderately stable against C. analis. Multivariate analyses revealed significant species- and condition-driven variation, with seed damage, emergence and developmental period, as key discriminators. Correlation funnel confirmed antibiosis as the predominant resistance mechanism, while antixenosis was species-specific, particularly against C. maculatus. Machine learning model predicted seed and insect traits as major contributors. Factorial Analysis of Mixed D and hierarchical clustering validated biologically meaningful grouping of resistant versus susceptible accessions, with biochemical traits enhancing separation of intermediate classes. Collectively, R. bracteata emerges as a robust multi-species resistance donor, and C. scarabaeoides as a species-specific donor. These multi-species resistant resources act as invaluable resources for introgression breeding to develop bruchid-resistant pigeonpea cultivars and highlight opportunities to dissect biochemical pathways and QTLs underlying resistance.