Breeding Strategies for Simultaneous Improvement in Anthracnose Disease Resistance and Economically Important Traits in French Bean

French bean (Phaseolus vulgaris L.) production in the tropics is threatened by heavy incidence of anthracnose disease causing substantial crop loss when infected at the early growth stages. Breeding strategies for enhanced productivity, high pod protein content combining resistance to anthracnose disease needs attention and are to be formulated.

Diverse genotypes with broad genetic base and phenotypic diversity in five bush and one pole types were crossed in a 6 × 6 half diallel mating design to estimate combining ability, mode of gene action and extent of heterosis for 11 quantitative traits. Statistical analyses were done with Windostat (ver. 8.0, Indostat Services, Hyderabad, India).

The additive genetic effect was evident for percent disease index (PDI) of anthracnose and ten pod weight. Rapid genetic gain can be achieved due to predominance of additive gene action and can therefore be selected in early generation through simple breeding methods. The remaining economic traits controlled by additive and non-additive gene effects could be improved through biparental mating, reciprocal recurrent selection, or diallel selective mating. Anthracnose disease resistant and high yielding cultivars can be developed utilizing good general combiners viz., Laxmi, Arka Sharath and Vaishnavi-264 with high gca effects. Although two cross combinations Arka Sharath × Lakshmi and Arjun × Arka Sharath showed significant heterobeltiosis in desired direction for PDI of anthracnose and other desirable horticultural traits but could not be exploited at commercial level due to complexity in hybridization. Identifying pure lines with resistance against anthracnose disease and favourable horticultural attributes could be accomplished in segregating generations of the prospective hybrids.