Avaliação de cultivares de azevém para produção de feno em diferentes estádios fenológicos.

Abstract

This research evaluated the agronomic characteristics of diploid and tetraploid ryegrass cultivars in differents phenological stages to haymaking in lowland soils. The experimental design used was randomized blocks with split plots and four cultivars of annual ryegrass (BRS Ponteio and FEPAGRO hp St. Gabriel, diploid, and; INIA Escorpio and KLM 138, tetraploid) placed in plots and three phenological stages (vegetative, pre-flowering and flowering), with four repetitions. It were evaluated: dry matter yield, leaf stem ratio, leaf weight ratio, tiller number, specific leaf area, crude protein, neutral detergent fiber and acid detergent fiber. The data were submitted to analysis of variance and the means were compared by Fisher's exact test LSD. In interaction case, it were used Student t the significance level established on 5% (P< 0.05) when were observed interactions between the factors. In all cultivars, the highest dry mass yield was obtained with harvest in the flowering stage. The tetraploid cultivars presented higher ratio in leaf stem in all growth stages, providing it a better quality hay, due to the lower proportion of structural matter in the forage. These tetraploid cultivars also had higher crude protein content in the forage during the vegetative stage, however, during the transition to the pre-flowering stage, lowering the concentration of this nutrient was more pronounced than observed in diploid cultivars. The neutral detergent fiber and acid detergent fiber presented similar behavior with the increase of fodder cycle, but tetraploid cultivars enable the production of quality hay, even with harvest on flowering.