Genetic control of plant architecture in the common bean (Phaseolus vulgaris L.)

More erect plant architecture has been a goal in the development of bean cu ltivars. Aiming to obtain more information about genetic control of traits related to plant architecture, this work was carried out between August 199 5 and July 1997 in the southern and Alto Sao Francisco regions, in the Stat e of Minas Gerais, Brazil. Initially, analyses were performed with individu al plants of parents and different segregant generations from the crosses C arioca-MG x H-4 and Carioca x FT-Taruma. In these experiments, besides degr ee of erectness, other traits were evaluated: ramification degree, internod e length, internode diameter and height of insertion of the first pod. Mean and variance components and heritability at an individual level were estim ated. Later, families derived from F-2 or F-3 plants of the same crosses we re evaluated for degree of erectness. Genetic and phenotypic variance betwe en family averages, heritabilities using Variance components, and realized heritability were estimated. Of the morphological traits, internode length varied the most. There was a predominance of additive effect in the control of this trait. Evaluating plant architecture with individual plants for de gree of erectness was not efficient. However, when families were used, gene tic parameter estimates confirmed the possibility of successful selection, especially if evaluated for a few generations and/or environments, despite the strong environmental influence on trait expression.