Avaliação de genótipos de capim-de-rhodes para características agronômicas e valor nutritivo no norte de Minas Gerais

Abstract

Pasture is the basis of ruminant production systems in Brazil. However, many of these face problems caused by environmental stress or due to inadequate management. When we approach environmental stress, it becomes important to study the adaptation of the plant to minimize the impacts of climate variations on the system. This allows a reliable recommendation of the best cultivars. The objective of the present study was to evaluate the production, morphological structure and nutritional quality of rhodes grass (Chloris gayana Kunth) in the northern region of Minas Gerais. The experimental design was in randomized blocks with 4 treatments (Callide, Mariner, KG2 and Sabre genotypes) and 6 replications. The Callide (6,169.7 kg/ha), Mariner (6,096.2 kg/ha) and Sabre (5,575.1 kg/ha) genotypes showed higher leaf dry mass production than KG2 (4,207.3 kg/ha). The KG2 genotype showed a higher proportion of stems and inflorescences than the others that did not differ from each other. There was no treatment effect on crude protein levels in summer and winter, which assumed values of 8.49 and 4.91%, respectively. The same result can be observed for the neutral detergent fiber contents, which assumed averages of 64.83 and 65.49% in summer and winter. The forage production accumulated in the dry period (winter) corresponded to 4.51% of the total production of the year. The in vitro dry matter digestibility of the KG2 genotype (60.67%) was lower than that of the Sabre (65.49%) and Callide (64.99%). The digestibility of the Mariner genotype (62.99%) did not differ statistically from the others in the summer. There was no effect of genotype on digestibility in the winter period, which presented an average value of 41.05%. The Callide, Mariner and Sabre genotypes are the best alternatives in relation to the KG2 genotype due to the higher production of leaves, lower proportion of stems and inflorescences and higher digestibility in the summer. All genotypes were very seasonal in the region.