Características agronômicas e valor nutricional de genótipos de sorgo

Abstract

The sorghum is a prominent crop for silage production, as it has desirable characteristics such as high soluble carbohydrate content, essential to the fermentation process, besides good mass productivity, high tolerance to drought, saline soils and good adaptation to different systems, thus increasing its planting area in the different Brazilian conditions, facilitating the development of several genotypes adapted to the forage conservation process. The objective of this work was to evaluate the agronomic characteristics, chemical composition and in situ degradability of sorghum genotypes. The experiment was carried out in the premises of CNPMS (National Center for Research on Corn and Sorghum) in Sete Lagoas, MG. Genotypes 12F02006, 12F03033, 13F26006, BRS655 and VOLUMAX were used in this study. In order to compare the agronomic and nutritional characteristics, a randomized complete block design was used and in situ degradability was considered subdivided plots scheme in the time in which the genotypes were the plots and the incubation times the subplots. The genotypes 13F2006, BRS655 and VOLUMAX presented the lowest yields of dry matter, with inferiority of 49.22% in relation to 12F02006 and 36.61% in 12F03033. The genotypes 12F03033 and 13F26006 were higher than the VOLUMAX for dry matter (DM), with averages of 30.73 and 31%, respectively. There was no difference for crude protein (CP), ethereal extract (EE) and total digestible nutrients (NDT) (P> 0.05). In relation to the levels of neutral detergent insoluble fiber (NDFc), acid detergent insoluble fiber (ADF) and lignin, the BRS655 genotype showed the lowest values, with mean values of 62.49; 35.55; and 4.77%, respectively. No difference was observed for potential degradability (PD), indigestible fraction (IF), and effective degradability (ED) at 2; 5 and 8% h-1 of (DM). As for the degradability of the NDF, genotype BRS655 was higher than the potentially degradable insoluble fraction (Bp), PD and ED at 2 and 5% h-1 . The 12F03033 genotype, considering dry matter yield, NDF content and effective degradability at 2 and 5% h-1 , presented a higher degradable fiber per area and at 8% h-1, the 12F02006 genotype was higher, considering that these two genotypes showed similarities in the effective fiber degradability to 8% h -1 . The genotypes 12F03033 and 12F02006 stood out, as they were the ones that better ally productivity and fiber quality, being the most indicated to the silage process.