Grain dry matter accumulation and grain filling period in irrigated rice

Abstract

The objective of this work was to determine the rate of accumulation of dry matter and the duration of the grain filling period of irrigated rice cultivars with different maturation groups and sowing dates. To determinate the rate and duration of the grain filling period, samples per cultivar were taken. The relation was adjusted between days after flowering and grain weight. The results indicated that the anticipation of the sowing date promoted a delay in the period of occurrence of the highest rate of grain filling. The late cycle cultivars had a longer duration of the grain filling period (31 days), in relation to the cultivars of early and medium cycle. Then, the cultivars with higher grain filling rates showed higher grain weight in R9, lower number of grain per panicle and shorter grain filling period. Thus, it was possible to conclude that there was a variation in the grain filling rate and the grain filling period of irrigated rice cultivars with different maturation groups, which in the late cycle cultivars had a lower rate and a longer duration in the grain filling period. Then, it was identified that the grain weight is associated with the grain filling rate.