Recurrent selection for broad‐spectrum resistance to anthracnose in common bean

Summary

This breeding study demonstrates that recurrent selection—a classical quantitative genetics method—can successfully combine resistance to multiple races of anthracnose in common bean by leveraging complementary resistance genes from ten diverse parental lines across five cycles of intercrossing, inoculation, and selection. The approach progressively increased the proportion of progenies with broad-spectrum resistance and achieved cumulative genetic gains of 38.75%, offering greater stability and durability than race-specific resistance strategies. This dynamic methodology may improve the longevity of anthracnose resistance in commercial cultivars by reducing vulnerability to pathogen breakdown.

UK applicability

Common bean is not a major UK field crop; however, the recurrent selection methodology for combining multiple-race pathogen resistance is transferable to UK-grown legumes and other crops vulnerable to polymorphic pathogens. The approach may inform UK plant breeding programmes seeking durable, multi-pathotype resistance without reliance on single major genes.

Key measures

Proportion of progenies resistant to multiple C. lindemuthianum isolates per selection cycle; genetic gain from Cycle 1 to Cycle 5 (38.75%) when evaluated against mixed-race pathogen inocula

Outcomes reported

The study measured the progressive increase in common bean progenies resistant to multiple races of Colletotrichum lindemuthianum across five selection cycles, achieving a cumulative genetic gain of 38.75% when evaluated against a mixture of isolates from four pathogen races.

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