Agronomic characteristics and chemical composition of eight sorghum hybrids [Sorghum bicolor (L.) moench]

This research was developed to evaluate the agronomic characteristics, chemical composition of the whole plants and their fractions of eight sorghum hybrids, to identify the adapted plants to dry environmental conditions and appropriated to silage production. The experiment was conducted according to a randomized block design, with eight treatments and three replications, to study the commercial hybrids AG-2005, BR-700 and MASSA-03, and the non commercial hybrids 498111,65E3,698005,698007 and 699005. There were no significant differences among hybrids in relation to the plant height, dry matter production and leaf proportion, it was observed highest stem content (43.3%) in the 498111 hybrid and lowest in the MASSA-03 (29.9%). The 65E3 showed highest panicle contents (43.2%), however the lowest value was observed in the 498111 hybrid (28.9%). The contents of dry matter, ashes, hemicellulose, neutral detergent insoluble nitrogen, acid detergent insoluble nitrogen and total digestible nutrients of the whole plant were similar among hybrids. It was observed different values of crude protein (6.5 to 8.8%), neutral detergent fiber (57.0 to 70.3%), acid detergent fiber (29.8 to 36.2%), cellulose (25.3 to 31.2%) and lignin (3.6 to 5.5%) of the hybrids. The content of soluble carbohydrates of hybrid 699005 (14.5%) was higher than the 698007 (9.6%). The hybrids showed differences on chemical composition of the leaf, stem, and panicle fractions. The dry matter and soluble carbohydrates contents of all hybrids were appropriate to the ensilage process. The average dry matter yield of all hybrids was 6.2 t/ha. This value was high considering the low rainfall during the experimental period. The Cluster analyses suggest a group of the sorghum hybrids with higher dry matter production (DMP), lower panicle percentage, and TDN content, and others with lower DMP, but higher panicle percentage, and TDN values.