Thermal requirement, yield and forage nutritive value of sorghum genotypes

Sorghum is mainly used for grain production; however, research is needed to know the forage potential and to select outstanding genotypes, considering different parameters. The objectives were to evaluate the forage performance of sorghum, through yield, morphological and nutritional variables, as well as to estimate the thermal requirement under subtropical conditions. A total of 13 genotypes were evaluated in a randomized complete block design, using analysis of variance, mean test and principal component analysis. Genotypes Fortuna and 197-1 had the highest total dry matter yields (24.6 t ha-1). Fortuna excelled in leaf yield, with 9.23 t ha(-1) and 197-1 in the stem component, with 14.96 t ha(-1). In the nutritive value variables, there were differences in crude protein, starch and crude fat, with yields of up to 94, 140 and 22 g kg(-1) of dry matter, respectively. Forage performance of sorghum is determined by genotype, which differ in thermal requirements (906 to 1539 GDD). Fortuna and 197-1 have potential to be considered for ruminant feeding in terms of nutritive value.