Comportamento de genótipos de feijão em temperaturas subótimas

Abstract

The bean crop is subjected to the occurrence of suboptimal temperatures during the field establishment in the state of Rio Grande do Sul, which can result in delays and stand failures, with consequent losses to the farmer. So, the purpose of this study was to test the general behavior of a group of 10 strains in the launch phase and three commercial cultivars when submitted to successive decreases in temperature. Moreover, aimed to test the adaptability and stability of each genotype. The variables used were the dry weight of the aerial part, dry weight of root, the relation between the aerial part and root, root length, aerial part length, relation between aerial part length and root, germination and speed index of germination. The trials were conducted in B.O.D., with randomized block design. The variance analysis was performed for each of the temperatures of each variables and conjoint analysis of variance for each variable. It was calculated the environmental indexes and the parameters of genotypes adaptability and stability in each of the variables. The successive decrease in temperature negatively affects the germination, the germination speed, the dry matter accumulation in aerial part and the length of aerial part and root of the genotypes tested. There is interaction between genotypes and temperatures. The variables dry matter of aerial part and root have identified negative effects of temperature beforehand, and the germination was less sensitive. The genotypes tested showed differences in the adaptability and stability. The L6 genotype proved to be predictable in all the analysis, being identified as promising for unfavorable environments regarding to growth of aerial part, root and dry matter accumulation of root and aerial part.