COMBINING ABILITY AND GENE ACTION OF MORPHOLOGICAL TRAITS AND SEED YIELD IN COMMON BEAN

Abstract

In 1992 twelve F₂ populations from all possible crosses among four parental bean (Phaseolus vulgaris L.) genotypes were evaluated under rainfed conditions in two locations in the State of Mexico. Evaluations were carried out following the Method I, Model II of Griffmg. Parental bean genotypes were: Flor de Mayo Bajío, Flor de Mayo M38, RIZ 30 and A 193. F₂ populations and parental genotypes were established at the onset of the rainy season in July in a randomized complete block design with five replicates. With the recorded data from both Iocations the GCA for each of the parental genotypes was calculated, as well as the type of gene action involved in the control of eight morphological traits and seed yield per plant. Results indicated larger additive effects for the hypocotile tickness, number of branches, seed weight, and number of seeds per pod, whereas deviations from dominance were important for number of nodes and pods per plant, straw weight and seed yield. Parental genotypes Flor de Mayo Bajío and Flor de Mayo M38 displayed highest GCA values for hypocotile tickness, number of branches, straw and seed weight. On the basis of trait complementation, the best croases with the four parental genotypes studied should be Flor de Mayo Bajío and Flor de Mayo M38 (Jalisco race) crossed to RIZ 30 (Mesoamerican) and A 193 (Nueva Granada). Results on maternal effects were positive only in A 193 and suggested that this genotype should be used in crosses as maternal parent.