Controle genético do número de flores e do vingamento floral em feijão

Abstract

The pods’ number per plant of bean (Phaseolus vulgaris L.) is one of the main primary components of grain yield. It depends on the number of flowers that are produced and the percentage of these flowers that give rise to pods, that is, flower set. Thus, information about the genetic control of the number of flowers and flower set in a given condition is one of the alternatives to evaluate the productive potential of a plant/cultivar and possible selection strategies. The objectives of this study was to understandthe genetic control of these traits and to verify if their estimate differs with the environmental conditions and the gene pool of origin. For this, a complete diallel was performed without the reciprocal ones, using six lines. The 21 treatments were evaluated in three harvests/generations - F2, F3 and F4 - during the 2015/2016 year. The experiment was conducted in a randomized block design with four replications. The plot had three rows with 4m. In the central rows There was a 1 m long screen receptacle to collect the flowers/pods and other parts of the plants that fell before harvest. The following traits were considered: number of pods / plant (X), number of flowers / plant (N), percentage of flower set / plant (V), number of grains / plant (Y), weight of 100 grains and grain / plant production (W). Using the means, a combined diallel analysis was performed applying the Griffing methodology (1956). The correlation between N, V and W was estimated later. The bean usually have a mean of 31.9 flowers/plant and a flower set percentage of 40.4%. The mean of the genitors that have Mesoamerican origin, in general, for N and V is higher than Andean genitors. The selection done by the breeders over the time did not contribute to increase N and V. The specific capacity ability (SCA) explained most of the variation for the number of total flowers, evidencing the dominance effect in order to increase the expression of the trait in its genetic control. However, for the flower set percentage, the dominance contribution was slightly lower than the general combining ability (GCC) and aiming the trait reduction. Indicating that for the genetic control of V, loci occur with additive effect and also dominance. The genitors differed in the GCC (gi) estimate for N and V. The genitors differed in the GCC (gi) estimate for N and V. the Mesoamerican lines always presented estimates of positive CGC for V. As higher as the number of total flowers, the percentage of flower set was smaller..We observed that the grain yield was greater when the number of flowers and flower set was greater. . These two traits are very influenced by the environment and should act as a strategy for greater stability of bean grainyield.