关键词: 水稻, 高产, 氮高效, 籽粒灌浆

Abstract: In order to clarify the grain filling characteristics of indica rice varieties with high yield and high N use efficiency  and their relationship with yield and nitrogen utilization, field experiments were conducted in 2014 and 2015, and hybrid Indica rice varieties with high yield and high nitrogen efficiency (HYHNE), high yield and medium nitrogen efficiency (HYMNE) and low yield and low nitrogen efficiency (LYLNE) were grown separately under their respective optimum N application amount to achieve maximum attainable yields. The differences of grain filling characteristics of rice cultivars in different types were investigated. The results showed that there were significant differences in grain filling characteristics among different cultivars and different grain positions. As for the superior grains, maximum grain-filling rate (GRmax), weight of a kernel at the time of maximum grain-filling rate (Wmax) and the average grain filling rate (GRmean) were all ranked in HYHNE > HYMNE > LYLNE; initial growth (R0), active grain-filling period (D) and effective filling time (T99) were all performed as HYHNE < HYMNE < LYLNE. However different tendency was found in inferior grains, their characteristics of GRmax, Wmax and GRmean were all performed as HYHNE > LYLNE > HYMNE, characteristics of R0, D and T99 were all performed as HYHNE < LYLNE < HYMNE. It was suggested that the cultivar of HYHNE had the characteristics of earlier grain filling initiation, faster filling rate and shorter effective filling time, regardless of grain position. The superior grains of cultivar of HYMNE filled well, but the inferior grains had the latest grain filling initiation, the slowest filling rate and the longest effective filling time. The filling characteristics of inferior grains might be the important reason limiting the further improvement of nitrogen efficiency in HYMNE cultivars.

Key words: rice, high yield, high N use efficiency, grain filling