Abst[Objective] This study was to understand the genetic dynamics of three-line hybrid rice, and explore the respective effect of sterile line and restoring line on grain characters of hybrid rica. [Method] Four three...Abst[Objective] This study was to understand the genetic dynamics of three-line hybrid rice, and explore the respective effect of sterile line and restoring line on grain characters of hybrid rica. [Method] Four three-line stedle lines and 27 restoring lines（cultivars） commonly culti- vated in Central China region were regarded as expadmental materials to conduct 4 x27NCII cross design, and the grain characters of three-line hybrid rico were analyzed at genetic and correlation levels. [ Result] Four characters of grain length, grain width, 1 000-grain weight and length- width ratio play the leading role in additive gene effect; these four characters were simultaneously influenced by male parent and female parent, but the effect from male parent was relatively larger. The grain length, grain width, 1 000-grain weight and length-width ratio all have high brood hedtabUities（ respectively 99.65%, 98.31%, 95.27% and 98.81% ）. Correlation analysis showed that grain length was positively correlated with 1 000-grain weight and length-width ratio at extremely significant level; 1 000-grain weight was positively correlated with grain length and length- width ratio at extremely significant level, and was insignificantly correlated with grain width; grain width was negatively correlated with grain length and length-width ratio at extremely significant level. Path analysis showed that the direct path coefficients of grain length, grain width and 1 0（30- grain weight to length-width ratio were 0.624 6, -0.555 9 and -0.015 8, respectively. [ Conclusion] This study systematically analyzed the effects of stedle line and restoring line on grain characters of hybrid rice, which provided theoretical basis for breeding high quality and yield hy- brid dce.展开更多
[Objective] The aim was to research relationship between SPAD decline index after full-heading stage （SDIFHS） and productivity of rice. fertilized with nitro- gen in order to provide theoretical and practical refere...[Objective] The aim was to research relationship between SPAD decline index after full-heading stage （SDIFHS） and productivity of rice. fertilized with nitro- gen in order to provide theoretical and practical references for selection and breed- ing of rice varieties. [Method] From 2008 to 2010, 18 mid-season hybrid rice vari- eties were researched every year to explore relationship＇ between SDIFHS and pro- ductivity of rice fertilized with nitrogen. [Result] The productivity of rice fertilized with nitrogen was of extremely significant positive corretation with SDIFHS, because the higher SPAD decline index is, the higher LAI decline index and the transformation ratio of dry matter to spikes in overground plant would be. [Conclusion] The re- search established a new method to predict productivity of rice fertilized with nitro- gen based on SPAD decline index.展开更多
Potassium is one of the most important nutrients for rice production in many areas of Asia, especially in southeast China where potassium deficiency in soil is a widespread problem. Field experiments were conducted fo...Potassium is one of the most important nutrients for rice production in many areas of Asia, especially in southeast China where potassium deficiency in soil is a widespread problem. Field experiments were conducted for four consecutive years in Jinhua City, Zhejiang Province, to determine utilization of nutrients (N, P and K) by inbred and hybrid rice and rice grain yields as affected by application of potassium fertilizer under irrigated conditions. Grain yield and nutrient harvest index showed a significant response to the NPK treatment as compared to the NP treatment. This suggested that potassium improved transfer of nitrogen and phosphorus from stems and leaves to panicles in rice plants. N and P use efficiencies of rice were not strongly responsive to potassium, but K use efficiency decreased significantly despite the fact that the amount of total K uptake increased. A significant difference between varieties was also observed with respect to nutrient uptake and use efficiency. Hybrid rice exhibited physiological advantage in N and P uptake and use efficiency over inbred rice. Analysis of annual dynamic change of exchangeable K and non-exchangeable K in the test soil indicated that non-exchangeable K was an important K source for rice. Potassium application caused an annual decrease in the concentration of available K in the soil tested, whereas an increase was observed in non-exchangeable K. It could be concluded that K fertilizer application at the rate of 100 kg ha-1 per season was not high enough to match K output, and efficient K management for rice must be based on the K input/output balance.展开更多
Root box experiments were conducted to evaluate the effects of N and NK levels in the root zone on shoot photosynthesis and root growth of hybrid and cultivar of rice (Oryza sativa L.) on two paddy soils (clayey and s...Root box experiments were conducted to evaluate the effects of N and NK levels in the root zone on shoot photosynthesis and root growth of hybrid and cultivar of rice (Oryza sativa L.) on two paddy soils (clayey and silty). The results showed that dry matter yields in the hybrid and the cultivar were considerably increased by NK supply, but the effect was greater for the hybrid. Supply of NK in the root zone significantly increased photosynthetic rate of the lower position leaf and the active green leaf area per plant, in which the effects were much more obvious in the hybrid rice than in the cultivar. High NK supply in the root zone stimulated the root growth, and decreased PH and increased the oxidation zone in the rhizosphere in both entries, but to a greater extent in the hybrid. The results indicated that higher NK levels were needed to maintain higher root activity and shoot photosynthetic capacity in rice, particularly in hybrid rice.展开更多
文摘Abst[Objective] This study was to understand the genetic dynamics of three-line hybrid rice, and explore the respective effect of sterile line and restoring line on grain characters of hybrid rica. [Method] Four three-line stedle lines and 27 restoring lines（cultivars） commonly culti- vated in Central China region were regarded as expadmental materials to conduct 4 x27NCII cross design, and the grain characters of three-line hybrid rico were analyzed at genetic and correlation levels. [ Result] Four characters of grain length, grain width, 1 000-grain weight and length- width ratio play the leading role in additive gene effect; these four characters were simultaneously influenced by male parent and female parent, but the effect from male parent was relatively larger. The grain length, grain width, 1 000-grain weight and length-width ratio all have high brood hedtabUities（ respectively 99.65%, 98.31%, 95.27% and 98.81% ）. Correlation analysis showed that grain length was positively correlated with 1 000-grain weight and length-width ratio at extremely significant level; 1 000-grain weight was positively correlated with grain length and length- width ratio at extremely significant level, and was insignificantly correlated with grain width; grain width was negatively correlated with grain length and length-width ratio at extremely significant level. Path analysis showed that the direct path coefficients of grain length, grain width and 1 0（30- grain weight to length-width ratio were 0.624 6, -0.555 9 and -0.015 8, respectively. [ Conclusion] This study systematically analyzed the effects of stedle line and restoring line on grain characters of hybrid rice, which provided theoretical basis for breeding high quality and yield hy- brid dce.
基金Supported by Southuest China Rice Innovation System and Crop High-yielding Project by Science and Technology (2011BAD02A05) Transformation Project of Agricultural Fruits into Capitals (2006GB2F000256)+2 种基金Sichuan Academic Leaders Training FundSichuan Rice Cultivation Key ProjectSichuan Financial Distribution Project~~
文摘[Objective] The aim was to research relationship between SPAD decline index after full-heading stage （SDIFHS） and productivity of rice. fertilized with nitro- gen in order to provide theoretical and practical references for selection and breed- ing of rice varieties. [Method] From 2008 to 2010, 18 mid-season hybrid rice vari- eties were researched every year to explore relationship＇ between SDIFHS and pro- ductivity of rice fertilized with nitrogen. [Result] The productivity of rice fertilized with nitrogen was of extremely significant positive corretation with SDIFHS, because the higher SPAD decline index is, the higher LAI decline index and the transformation ratio of dry matter to spikes in overground plant would be. [Conclusion] The re- search established a new method to predict productivity of rice fertilized with nitro- gen based on SPAD decline index.
基金Project supported by the International Fertilizer Industry Association (IFI), France the Potash & Phos-phate Institute (PPI), USA and Canadathe International Potassium Institute (IPI), Switzerland.
文摘Potassium is one of the most important nutrients for rice production in many areas of Asia, especially in southeast China where potassium deficiency in soil is a widespread problem. Field experiments were conducted for four consecutive years in Jinhua City, Zhejiang Province, to determine utilization of nutrients (N, P and K) by inbred and hybrid rice and rice grain yields as affected by application of potassium fertilizer under irrigated conditions. Grain yield and nutrient harvest index showed a significant response to the NPK treatment as compared to the NP treatment. This suggested that potassium improved transfer of nitrogen and phosphorus from stems and leaves to panicles in rice plants. N and P use efficiencies of rice were not strongly responsive to potassium, but K use efficiency decreased significantly despite the fact that the amount of total K uptake increased. A significant difference between varieties was also observed with respect to nutrient uptake and use efficiency. Hybrid rice exhibited physiological advantage in N and P uptake and use efficiency over inbred rice. Analysis of annual dynamic change of exchangeable K and non-exchangeable K in the test soil indicated that non-exchangeable K was an important K source for rice. Potassium application caused an annual decrease in the concentration of available K in the soil tested, whereas an increase was observed in non-exchangeable K. It could be concluded that K fertilizer application at the rate of 100 kg ha-1 per season was not high enough to match K output, and efficient K management for rice must be based on the K input/output balance.
文摘Root box experiments were conducted to evaluate the effects of N and NK levels in the root zone on shoot photosynthesis and root growth of hybrid and cultivar of rice (Oryza sativa L.) on two paddy soils (clayey and silty). The results showed that dry matter yields in the hybrid and the cultivar were considerably increased by NK supply, but the effect was greater for the hybrid. Supply of NK in the root zone significantly increased photosynthetic rate of the lower position leaf and the active green leaf area per plant, in which the effects were much more obvious in the hybrid rice than in the cultivar. High NK supply in the root zone stimulated the root growth, and decreased PH and increased the oxidation zone in the rhizosphere in both entries, but to a greater extent in the hybrid. The results indicated that higher NK levels were needed to maintain higher root activity and shoot photosynthetic capacity in rice, particularly in hybrid rice.
