FORAGE PRODUCTION, GRAIN-YIELD, AND PROTEIN-CONTENT IN DUAL-PURPOSE TRITICALE GROWN FOR BOTH GRAIN AND FORAGE

The use of cereal crops for both forage and grain production is practiced in many parts of the world. Quantity and quality of forage and grain with this dual use is strongly influenced by seeding date, cutting frequency and growth stage. The effect of two seeding dates and three cutting frequencies on forage production, grain yield, forage and grain protein content, and several associated characteristics of triticale (xTriticosecale Witt.) was determined in 1990 and 1991 at three field locations in southern Spain. Seeding date was less influential on forage and grain production than cutting treatments. Forage harvest significantly reduced grain yield 19.1 to 54.7% with one cutting and 46.6 to 76.2% with two cuttings. Plant height was reduced 5.6 to 18.8% with one cutting and 16.4 to 43.3% with two cuttings. Grain protein yield was reduced 18.6 to 53.7% with one cutting and 47.9 to 72.8% with two cuttings. Grain protein content increased 5.6 to 23.3% with one cutting and 8.0 to 32.0% with two cuttings at the rainfed sites, but not under irrigated conditions. Forage protein content was negatively related to forage yield both in rainfed (r = -0.824) and irrigated (r = -0.952) environments, probably due to a dilution effect. An inverse linear relationship was found between grain yield and protein content (r = -0.901) in the four rainfed experiments, probably from differences in accumulation of starch. Under irrigated conditions and high soil fertility, cuttings did nut affect the final percentage of protein in the grain, although grain yield decreased. An inverse relationship was found between the rainfall measured during the triticale growing season and the mean protein content in the grain (r = -0.911) under rainfed conditions.