DRY-MATTER ACCUMULATION RATE AND DURATION OF GRAIN FILLING PERIOD IN WHEAT

Wheat (Triticum aestivum, L.) crops grown in Santa Maria region, RS, Brazil, are often subjected to high temperatures during the grain filling period, which may reduce grain yield. Rate and duration of grain filling period were determined for 25 wheat cultivars in four environments to evaluate genotypic variation for this two traits. The duration (days) mean of four environments, from anthesis to physiological maturity was 39 days, while the duration of the life cycle from seeding to physiological maturity was 137 days, corresponding to 592 and 1.621 accumulated growin/degree days respectively. Grain filling rate was 0,925 mg/day, and the mean grain dry weight estimated at physiological maturity was 35 mg. No genetic variability was found for rate of dry matter accumulation and accumulated growing degree days from anthesis to physiological maturity of the grain, among wheat cultivars evaluated.