Diversidade genética, resistência a antracnose e predição do potencial de população segregante de Phaseolus lunatus

Abstract

Phaseolus lunatus, known as Lima bean, Sieva bean or butter bean is a tropical legume with great genetic diversity and high production potential as it adapts to different environmental conditions. Due to its high nutritional value, the bean is present in the diet of different populations as it is an important source of vegetable protein. In Brazil, as it is a convergence zone between domestication centers, there is high diversity. Despite this, little is known about the diversity present in seeds commercialized in Northeastern Brazil and how much they can help understand and improve germplasm in terms of resistance to Colletotrichum truncatum. The objective of this work was to evaluate the diversity of resistance to anthracnose in varieties and verify the segregation of resistance in contrasting crosses. The varieties were characterized by morphoagronomic and genetic parameters to verify the diversity and determine the genetic structure of 29 fava bean genotypes from cross-breeders and/or producers in Alagoas and Pernambuco. The segregation of morphoagronomic characters and the resistance of two fava bean varieties were evaluated in one progeny (F2) obtained from a contrasting cross for anthracnose resistance. In the study of the 29 genotypes, differentiation was observed according to the state of origin and type of seeds. Molecular markers evidenced the presence of three subpopulations unrelated to the provenance, type of seed, or gene pool. The characters related to the production of nodules and resistance to C. truncatum showed statistical differences with the formation of distinct groups. In the crossbreeding trial, the segregation in F2 evidenced the dominance in the anthracnose resistance characters, plant size, flowering, and seed maturation. The results will serve as a basis for future genetic improvement programs for the species in the world, but mainly in Brazil, considering that it is a fundamental step for obtaining genotypes that meet the farmer’s demand.

Keywords: lima beans, crossing, resistance, complementary gene interaction, landraces.