Inheritance of Genetic Resistance to Anthracnose in Lima Beans: Analysis and Implications for Breeding

Abstract

Lima bean (Phaseolus lunatus L.) is a crop of notable agricultural importance. However, its production is severely affected by anthracnose, a disease caused by the fungus Colletotrichum truncatum. This study aimed to investigate the genetic inheritance of anthracnose resistance in lima beans to support breeding efforts. Segregating populations (F₁ and F₂) derived from crosses between resistant and susceptible genotypes were used. All plants with their first pair of developed leaves were inoculated with a conidia suspension of the CT4 isolate of C. truncatum (10⁶ conidia/mL) to study their inheritance. Phenotypic data were collected and analysed to identify inheritance patterns and resistance loci. According to the chi-square (χ²) test, the segregating ratio of 1:0 (resistant:susceptible) was accepted for the F₁ generation, and the ratio of 3:1 (resistant:susceptible) was accepted in the F₂ generation. These results indicate that resistance to C. truncatum in lima beans is conditioned by a single gene, showing evidence of dominant monogenic inheritance. The results offer pathways to develop resistant cultivars, improving crop productivity and sustainability.