Parâmetros genéticos e caracterização de acessos de Desmanthus spp. submetidos a diferentes alturas de corte

Abstract

Legumes contribute to improving the quality of the animals'diet, as well as to the chemical and biological properties of the soil. Plants of the genus Desmanthus are selected by grazing animals, due to their high palatability. Native and ecologically adapted to the semi-arid conditions. The use of morphological and productive characters for evaluation in accesses is important as it allows the identification of contrasting individuals. The objective was to evaluate morphological and productive characteristics in six accessions of Desmanthus spp. (5G, 6G, 7G, 8AU, AS and SA) subjected to two cutting intensities, it was estimated the repeatability of morphological and productive characteristics in accessions of Desmanthus spp. handled under two cutting intensities (40 and 80 cm). Data were submitted to analysis of variance: variance analysis, principal component analysis (covariance) and structural analysis. There was a significant difference in relation to the cut height for the plant height and stem diameter variables, and the plants cut at 80 cm showed the highest values (94.48 cm and 0.45 cm, respectively). For the number of leaves per branch, it was observed that the 7G access (13.78 leaves/branch) did not differ only from the AS access (12.07 leaves/branch). There was interaction between access and cutting intensities for the variables number of branches per plant, diameter at the base of the plant and leaf/stem ratio. There is high genetic variability among the accessions of Desmanthus to the morphological characteristics submitted to the cut intensities of 40 cm and 80 cm. The repeatability estimates were higher when the plants were cut at 80 cm in height, reflecting less need for cuttings for the number of leaves per branch (0.56), stem diameter (0.68), leaf width (0.99), leaf perimeter (0.53), sheet production (0.51), stem production (0.63), total production (0.68) and leaf/stem ratio (0.60).. Inheritability values higher than 80% were observed for total production, leaf production and stem production, regardless of the plant harvest height. The analyzed variables had coefficients of determination above 80%. It is concluded that the seven customs applied in the present work make it possible to select accessions of Desmanthus spp. with desirable characteristics, with 85% accuracy. Desmanthus accesses evaluated showed genetic variability, and there is possibility of gain in future selections.