Características agronômicas e composição química entre híbridos de sorgo forrageiro.

Abstract

The objective was to determine the agronomic characterization, chemical composition of the plant and silage among hybrids of forage sorghum. Twenty-five sorghum hybrids were tested in a randomized block design with three replicates. The number of tillers in the plant was evaluated, total plant height, leaf/stem ratio and live matter/dead mass, green and dry mass yield, leaf dry mass, stem, panicle, grains and dead mass, and chemical composition. In the silage, pH, ammonia nitrogen (N-NH3) and chemical composition were measured. Two analyzes were performed for growth, production and chemical omposition of the plant and silage among sorghum hybrids. The first analysis was performed by the Scott-Knot procedure with significance of P <0.05. In the second, the multivariate analysis was performed in relation to the agronomic characteristics, chemical composition and silage based on the main components of the clusters, dispersion plot and genetic correlation. For multivariate analysis, the means were compared using the Student Newman Keuls (SNK) test for significance of P<0.05. The hybrid 9929036 presented higher number of tiller.Four hybrids had mean heights of 234.8, 208.9, 206.6 and 202.2 respectively, 947252, SF11, 9929026 and 12F042150. Hybrids 947252, FEPAGRO18,12F042226, SF11 presented better morphological characterization. On the other hand, for the dry matter content ideal for silage, all the hybrids presented better results, except for FEPAGRO19 and 12F042496, which presented out of the recommended range (28 to 40%). The silages of the hybrids PROG 134 IPA, FEPAGRO 19, FEPAGRO 11, 12F042224, 9929012, 9929026 and 947216 presented higher dry matter (DM) contents, ranging from 371.0 to 417.2 ± 18.2 g kg-1. According to the Ward grouping method the hybrids were grouped into 4 groups, I, II, III and IV, and group III excelled in relation to the others. The sorghum hybrids 9929030, 12F042224, 12F042150, FEPAGRO19, FEPAGRO11 are recommended for the production of silage in the semi-arid region.