Forage value of tall fescue as affected by its growth stage
This research was aimed at testing the effect of genotype on forage quality of tall fescue at different growth stages and selecting the most promising plants. Genotypes were collected from various locations. Seeding annual crops with tall fescue was avoided. In the collection and hybrid nurseries plants were seeded in bunches, breeding and verification nurseries - in rows (planting width of 45 and 15 cm, respectively). Annual fertilization rates in autumn: potassium - 90, phosphorus - 60, nitrogen - 60 kg ha-1 before cutting. Genotypes were tested under the simulation of pasture (four cuts, the first cut - when reaching ripening stage, the following ones - after 30, 30 and 45 days), hayland-pasture (three cuts, the first one - at heading time, the following cuts - after 30 and 45 days) and hayland conditions (the first cut - at flowering time, the second one - 45 days after the first cut). For chemical tests samples were collected in parallel with cutting. Green mass weighing was carried out at tillering, early heading, early flowering stages as well as under plant aftergrowth. Green mass and absolutely dry substance were accounted from plots of 5 m2 in triplicate. Testing 23 genotypes of tall fescue proved them to be suitable for plant breeding projects and forage production, and such traits were analyzed as crude protein, water soluble carbohydrates, crude fiber, sugar-to-protein ratio and dry matter digestibility at different growth stages. Plant digestibility dropped if cutting happened after the shooting stage. Optimal sugar-to-protein ratio was observed at heading-early flowering stage.