通讯机构：
[Huang, Min] H;Hunan Agr Univ, Coll Agron, Crop & Environm Res Ctr Human Hlth, Changsha, Hunan, Peoples R China.
摘要：
Glutelin and prolamin are the two major proteins in rice grains. Grain content of glutelin is considerably higher than that of prolamin in rice, but there is limited information on the factors determining the different grain contents of glutelin and prolamin. To address this knowledge gap, the present study compared final weight per grain and accumulation characteristics of glutelin and prolamin in four rice cultivars. Results showed that final glutelin weight per grain was 3.24-3.95 times higher than final prolamin weight per grain. Glutelin and prolamin accumulation processes were well fitted by the logistic equation. The initial, maximum, and mean accumulation rates of glutelin were 1.69-4.67 times higher than those of prolamin. The active accumulation duration of glutelin was 2.9-5.1 d longer than that of prolamin. These results indicate that both higher accumulation rate and longer active accumulation duration are responsible for the higher final weight per grain of glutelin compared to prolamin in rice.
通讯机构：
[Huang, Min] H;Hunan Agr Univ, Coll Agron, Crop & Environm Res Ctr, Changsha 410128, Hunan, Peoples R China.
摘要：
Low light is a common environmental factor that adversely affects rice yields. This study was conducted to evaluate the combined effect of hill density and nitrogen (N) fertilizer rate on yield attributes in hybrid rice under low-light conditions. Field experiments were conducted in 2014 and 2015. Two hybrid rice cultivars (Y-liangyou 1 and Luoyou 9348) were grown under combinations of three hill density levels (high, 40 x 10(4) hills ha(-1); moderate, 27 x 10(4) hills ha(-1); low, 14 x 10(4) hills ha(-1)) and two N rate levels (high, 240 kg ha(-1); moderate, 143-148 kg ha(-1)), and shaded from heading to maturity. Grain yield was highest in the combination of high hill density and moderate N rate and significantly declined with decreasing hill density combined with increasing N rate for both cultivars in both years. Averaged across two cultivars and two years, grain yield declined by about 4% for each 10% decrease in hill density combined with each 10% increase in N rate. A significant reduction in spikelet filling percentage was observed with decreasing hill density combined with increasing N rate in Y-liangyou 1 in 2015 and Luoyou 9348 in 2014. The same trend was observed for grain weight in Y-liangyou 1 in 2014 and Luoyou 9348 in 2015. These results indicate that adopting the practice of decreasing hill density combined with increasing N rate can result in poor grain filling and consequently yield decline in hybrid rice under low-light conditions.
通讯机构：
[Huang, Min] H;Hunan Agr Univ, Coll Agron, Crop & Environm Res Ctr, Changsha, Peoples R China.
摘要：
High yields of mechanized intensive rice-based cropping systems, e.g. double-season cropping using early- and late-season rice, are important to ensure national food security in China. However, few studies addressing the relationship between grain weight and grain yield of early-season rice under machine-transplanted conditions. A field experiment was conducted to determine the critical grain-filling characteristics and related physiological aspects that contribute to high grain weight in machine-transplanted early-season rice. The results showed that grain yield was significantly positively correlated with grain weight but not with panicles per m2, spikelets per panicle, and spikelet-filling percentage. Furthermore, this study demonstrated that there was a significant positive correlation between grain weight and mean grain-filling rate, which was significantly positively correlated with harvest index and grain cytokinin content. These results indicate that high grain-filling rate driven by good transport of assimilates to grains and strong grain sink strength is responsible for high grain weight in machine-transplanted early-season rice.
通讯机构：
[Huang, Min] H;Hunan Agr Univ, Coll Agron, Crop & Environm Res Ctr, Changsha, Hunan, Peoples R China.
摘要：
Translocation of biomass produced during pre-heading to grains is a determinant of grain yield, but also plays an important role in adaptation to unfavorable environments during post-heading in rice. In this study, field experiments were conducted to determine the critical factors that regulate biomass translocation in rice. Biomass translocation and production characteristics of two rice hybrids (Guiliangyou 2 and Y-liangyou 1) were compared between two site-year environments (Naning-2014 and Yongan-2018). Results showed that biomass translocation parameters (biomass translocation amount and rate and contribution of biomass translocation to filled grain weight) and ratio of biomass production during pre-heading to post-heading (BPpre/BPpost ratio) decreased in Guiliangyou 2 but increased in Y-liangyou 1 with the environment change from Nanning-2014 to Yongan-2018. The decreased BPpre/BPpost in Guiliangyou 2 was attributable to increased biomass production during post-heading (BPpost), while the increased BPpre/BPpost ratio in Y-liangyou 1 was due to increased biomass production during pre-heading (BPpre). Higher cumulative incident solar radiation and larger diurnal temperature variation were responsible for the increased BPpost in Guiliangyou 2 and the increased BPpre in Y-liangyou 1 grown in Yongan in 2018 compared to in Nanning in 2014. The results of this study indicate that changes in biomass translocation and production with environment (climate) in rice are dependent on genotype and that the BPpre/BPpost ratio is an important factor regulating biomass translocation in rice.
关键词：
Rice;Yield;Fertilizer;Nitrogen use efficiency
摘要：
Fertilizer plays an important role in increasing rice yield. More than half of all fertilizer applied to the field is not taken up, resulting in environmental damage and substantial economic losses. To address these concerns, a low-cost, coated compound fertilizer named “Xiang Nong Da” (XND), requiring only a single basal application, was studied. A two-year field experiment was conducted to test the effects of XND application on rice yield and nitrogen fertilizer use efficiency. An ordinary uncoated compound fertilizer (UNCF), with 20% more nutrients and split application was selected as the control. The yield of XND-treated rice was only 3.1% lower than that of the control, an insignificant difference. There were no significant differences between N use efficiency indices of the two fertilizer treatments except for N partial factor productivity (PFP_N). PFP_N of XND treatment was 19.7%–23.2% higher than the control, a significant difference. This result indicates that a 20%decrease inNapplication rate is possible with XND without yield reduction and with savings in both labor and time.
摘要：
在湖南长沙以超级稻Y两优1号为材料,研究了机插秧条件下栽插密度和施氮量对产量表现及氮肥利用率的影响。结果表明:产量随机插密度增加而增加,随施氮量的增加先增后降,机插密度和施氮量均通过增加有效穗数来增加产量;产量最高的处理组合为N1D1(施氮量170 kg /hm~2, 密度36.4万穴/hm~2, 产量9.57 t /hm~2), 其次为N1D2(施氮量170 kg /hm~2, 密度为28.6万穴/hm~2, 产量9.45 t /hm~2)和N2D1(施氮量240 kg /hm~2, 密度为36.4万穴/hm~2, 产量9.38 t /hm~2) 。降低施氮量或增加机插密度能提高氮肥吸收利用率和氮肥偏生产力。在施氮量为170 kg /hm~2、机插密度为28.6万~ 36.4万穴/hm~2条件下,既可以获得高产,又可以提高氮肥利用率。
