Abstract: The grain filling processes of paddy rice and upland rice under conventional paddy cultivation (PC) and plastic film mulched dry cultivation (DC) were fitted by Richards growth equation to study the difference in grain filling properties between the two types of rice. Results showed that effective panicles and grain weight of paddy rice decreased significantly under DC compared to those under PC,leading to significant reduction in grain yield of paddy rice under DC. In comparison with PC, DC reduced grain filling rates of both the superior and inferior grains, shortened active grain filling period, weakened initial grain filling potential of both the superior and medium grains and delayed occurrence of the maximum grain filling rate of paddy rice. In addition, under the DC condition, paddy rice had small difference in the time reaching the maximum grain filling rate between superior grains and inferior ones, so the grain filling of the inferior grains was worsened. Moreover, the difference in grain filling rate between the superior grains and inferior ones was further enlarged in paddy rice under DC relative to PC. As a result, paddy rice had lower seed setting rate and grain weight under DC than those under PC. Less variations in grain filling, grain yield and its components between DC and PC were found in upland rice relative to paddy rice. Compared to paddy rice, upland rice showed lower initial grain filling potential, especially for the superior and medium grains, stronger competition for assimilates in both superior and medium grains at early and middle filling stages, leading to less availability of assimilates to the inferior grains, which could be attributed to low seed setting rate, grain weight and finally low yield. Results also showed that upland rice had the less variation in the parameters related to grain filling processes in comparison with paddy rice under DC. Under the DC condition, the lower grain filling rate and longer active grain filling period were found in paddy rice relative to upland rice. Thus paddy rice showed greater difference in synchronism of grain filling between the superior and inferior grains relative to upland rice.

Key words: paddy rice, upland rice, water management, grain filling, growth analysis

摘要： 应用Richards方程对水作和旱作水稻与陆稻的籽粒灌浆过程进行拟合，研究两种稻灌浆特性在不同水分管理条件下的差异。结果表明，与水作相比，水稻旱作穗数和粒重明显降低，产量下降；强势粒和弱势粒的灌浆速率降低，活跃灌浆期缩短，强势粒和中势粒的起始生长势减弱，到达最大灌浆速率的时间延迟，强、弱势粒进入灌浆盛期的间距缩短，从而影响弱势粒的灌浆，强、弱势粒灌浆速率的差异增大，最终导致粒重和结实率降低。陆稻旱作与水作相比，除活跃灌浆期略有缩短以及强、弱势粒进入灌浆盛期的间隔略有延长外，整体上灌浆过程变化不大。与水稻相比，陆稻在两种水分条件下灌浆过程和产量及其构成因子的差异较小，表现为籽粒灌浆的起始生长势特别是强、中粒位势的起始生长势低，灌浆前、中期灌浆较强，强、中势籽粒对同化物的激烈竞争使弱势粒灌浆变差，籽粒灌浆期短，特别是灌浆后期持续时间短，导致结实率和粒重低，最终影响产量。旱作条件下，水稻与陆稻相比，籽粒灌浆速率较小，活跃灌浆期较长，强、弱势粒灌浆呈现明显的异步性。

关键词: 水稻, 陆稻, 水分管理, 灌浆, 生长分析