Effects of cultivation methods on grain-filling and chalky grains of upland and paddy rice

Chinese. 揭示种植方式对籽粒灌浆及垩白的影响。连续2年以中旱3号（陆稻）和武香粳99-8（水稻）为供试材料，设置覆膜旱种和裸地旱种2种旱种方式，以水层湿润灌溉为对照进行对比试验。与水种（对照）相比，陆稻覆膜旱种的产量显著低于对照，而水稻覆膜旱种的产量与对照无显著差异，裸地旱种的产量均较对照显著降低。陆稻旱种（覆膜旱种和裸地旱种）后强、弱势粒的相对起始灌浆势（R0/W）、最大灌浆速率（Gmax）、平均灌浆速率（G）均大于对照，活跃灌浆时间（D）小于对照，粒重均高于对照，垩白粒率显著低于对照。水稻旱种后强、弱势粒的R0/W、Tmax和粒重与陆稻旱种的结果相反。水稻覆膜旱种的垩白粒率与对照无显著差异，裸地旱种的垩白粒率显著下降。水稻和陆稻旱种的垩白度均显著减小。稻米的垩白粒率与籽粒的Gmax和G呈极显著和显著负相关。水稻和陆稻旱种可以增大籽粒的灌浆速率，改善稻米的外观品质。

English. The effects of cultivation methods on grainfilling and chalky grains were studied with upland rice of Zhonghan 3 (japonica) and paddy rice of Wuxiangjing 99-8 (japonica) as materials. Three different cultivation methods of moist cultivation (MC, control), plastic film mulching cultivation (PFMC) and bare cultivation (BC) were set up. The results showed that, compared with the MC, the grain yield was significantly lower under PFMC for upland rice, but there was no significant difference in grain yield between PFMC and MC for paddy rice. BC significantly reduced grain yield for both upland and paddy rice. Superior and inferior grains of upland rice had higher relatively grain-filling potential (R0/W), higher maximum grain-filling rate (Gmax), higher mean grain-filling rate (G) and higher grain weight, shorter time reaching the maximum grain-filling rate (Tmax) and lower percentage of chalky grains under dry cultivation (PFMC and BC) than under MC. Paddy rice showed opposite trends in R0/W and Tmax under dry cultivation. There was no significant difference in the percentage of chalky grains between PFMC and MC for paddy rice, whereas BC significantly reduced the percentage of chalky grains. The chalkiness was significantly decreased under dry cultivation for both upland and paddy rice. The percentage of chalky grains was very significantly and significantly negatively correlated with Gmax and G. The results suggested that dry cultivation could increase grain-filling rate and improve the appearance quality for both upland and paddy rice.