Developing high-yielding rice(Oryza sativa L.)cultivars depends on having a better understanding of nitrogen(N) accumulation and translocation to the ear during the reproductive stage.Field experiments were carried ou...Developing high-yielding rice(Oryza sativa L.)cultivars depends on having a better understanding of nitrogen(N) accumulation and translocation to the ear during the reproductive stage.Field experiments were carried out to evaluate the genetic variation for N accumulation and translocation in different Japonica rice cultivars at different N rates and to identify any relationship to grain yield in southeast China.Four Japonica cultivars with similar agronomic characteristics were grown at two experimental sites in 2004 with three N rates of 0,60,and 180 kg N ha^(-1).Dry weights and N contents of rice plants were measured at tillering,initiation,anthesis,and maturity.Grain yields exhibited significant differences (P<0.05)among the cultivars and N application rates.Increasing N rates improved N uptake at anthesis and maturity in all four cultivars(P<0.05).N translocation from vegetative organs to the grains increased with enhanced N rates (P<0.05).N translocation to the grains ranged from 9 to 64 kg N ha^(-1)and N-translocation efficiency from 33% to 68%. Grain yield was linear to N uptake at anthesis(r^2=0.78^(**))and N translocation(r^2=0.67^(**)).Thus,cultivars with a high N uptake at anthesis,low residual N in the straw at maturity,and appropriate low N fertilizer supply in southeast China should efficiently increase N-recovery rate while maintaining grain yield and soil fertility.展开更多
The major QTL-qSB-9^Tq conferring partial resistance to rice （Oryza sativa L.） sheath blight （Rhizoctonia solani Kvhn） has been verified on chromosome 9 of the indica rice cultivar, Teqing. In this study, the pros...The major QTL-qSB-9^Tq conferring partial resistance to rice （Oryza sativa L.） sheath blight （Rhizoctonia solani Kvhn） has been verified on chromosome 9 of the indica rice cultivar, Teqing. In this study, the prospect of this QTL utilized in molecular breeding program of japonica rice for sheath blight resistance was investigated. Most of the japonica rice cultivars showed lower level of sheath blight resistance than the indica rice cultivars. At the corresponding site of qSB-9^Tq, nine typical japonica rice cultivars from different ecological regions or countries proved to possess the susceptible allele（s）. Introgression of qSB-9^Tq into these cultivars enhanced their resistance level by decreasing sheath blight score of 1.0 （0.5-1.3）, which indicated that qSB-9^Tq had a large potential in strengthening the resistance of japonica rice to sheath blight. The use of the three molecular markers, which were polymorphic between Teqing and many japonica rice cultivars, promotes the application of qSB-9^Tq in a concrete molecular breeding program.展开更多
以江苏省近60年来各阶段具有代表性的12个中粳稻品种（含超级稻）为材料。依据种植推广年代结合株型和基因型将其分为20世纪50年代、60年代、70年代、80年代、90年代和2000年以后6个类型,进行0N （不施氮,0N）、240 kg hm-2（中氮, MN）...以江苏省近60年来各阶段具有代表性的12个中粳稻品种（含超级稻）为材料。依据种植推广年代结合株型和基因型将其分为20世纪50年代、60年代、70年代、80年代、90年代和2000年以后6个类型,进行0N （不施氮,0N）、240 kg hm-2（中氮, MN）和360 kg hm＾-2（高氮, HN）3种氮肥用量处理,并观察其对水稻产量和群体质量的影响。结果表明,产量随品种改良逐步提高,在0N、MN和HN条件下,由20世纪50年代早期品种到2000年以后的超级稻品种,产量增幅分别为4.45～4.64、5.89～5.93和8.45～8.62 t hm＾-2。2000年以前的中粳稻品种产量表现为MN＞HN＞0N；2000年以后的超级稻品种则表现为HN＞MN＞0N。2000年以前的中粳稻品种在MN处理下具有较高群体质量指标（茎蘖成穗率、抽穗至成熟期的干物质积累、有效叶面积和高效叶面积指数、粒叶比、着粒密度、剑叶光合速率和根系氧化力）,2000年以后的超级稻品种则在高氮处理下具有较高的群体质量指标。这些结果表明,早期品种对氮肥响应较现代超级稻品种敏感,超级稻品种则在高氮水平下具有更高的产量。群体质量的改善是品种改良增加产量以及超级稻品种在高氮水平下物质生产和产量提高的重要原因。展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.30390082 and 3027079)the Science and Technology Committee of Jiangsu Province,China(No.BE2005369).
文摘Developing high-yielding rice(Oryza sativa L.)cultivars depends on having a better understanding of nitrogen(N) accumulation and translocation to the ear during the reproductive stage.Field experiments were carried out to evaluate the genetic variation for N accumulation and translocation in different Japonica rice cultivars at different N rates and to identify any relationship to grain yield in southeast China.Four Japonica cultivars with similar agronomic characteristics were grown at two experimental sites in 2004 with three N rates of 0,60,and 180 kg N ha^(-1).Dry weights and N contents of rice plants were measured at tillering,initiation,anthesis,and maturity.Grain yields exhibited significant differences (P<0.05)among the cultivars and N application rates.Increasing N rates improved N uptake at anthesis and maturity in all four cultivars(P<0.05).N translocation from vegetative organs to the grains increased with enhanced N rates (P<0.05).N translocation to the grains ranged from 9 to 64 kg N ha^(-1)and N-translocation efficiency from 33% to 68%. Grain yield was linear to N uptake at anthesis(r^2=0.78^(**))and N translocation(r^2=0.67^(**)).Thus,cultivars with a high N uptake at anthesis,low residual N in the straw at maturity,and appropriate low N fertilizer supply in southeast China should efficiently increase N-recovery rate while maintaining grain yield and soil fertility.
基金the National High Technology Research and Development Program of China (863 Program) (No. 2006AA10Z165, 2006AA10A103 and 2007AA10Z191)the Ministry of Agriculture of China (No. nyhyzx07-049)the 948 Program (No. 2006-G51).
文摘The major QTL-qSB-9^Tq conferring partial resistance to rice （Oryza sativa L.） sheath blight （Rhizoctonia solani Kvhn） has been verified on chromosome 9 of the indica rice cultivar, Teqing. In this study, the prospect of this QTL utilized in molecular breeding program of japonica rice for sheath blight resistance was investigated. Most of the japonica rice cultivars showed lower level of sheath blight resistance than the indica rice cultivars. At the corresponding site of qSB-9^Tq, nine typical japonica rice cultivars from different ecological regions or countries proved to possess the susceptible allele（s）. Introgression of qSB-9^Tq into these cultivars enhanced their resistance level by decreasing sheath blight score of 1.0 （0.5-1.3）, which indicated that qSB-9^Tq had a large potential in strengthening the resistance of japonica rice to sheath blight. The use of the three molecular markers, which were polymorphic between Teqing and many japonica rice cultivars, promotes the application of qSB-9^Tq in a concrete molecular breeding program.
文摘以江苏省近60年来各阶段具有代表性的12个中粳稻品种（含超级稻）为材料。依据种植推广年代结合株型和基因型将其分为20世纪50年代、60年代、70年代、80年代、90年代和2000年以后6个类型,进行0N （不施氮,0N）、240 kg hm-2（中氮, MN）和360 kg hm＾-2（高氮, HN）3种氮肥用量处理,并观察其对水稻产量和群体质量的影响。结果表明,产量随品种改良逐步提高,在0N、MN和HN条件下,由20世纪50年代早期品种到2000年以后的超级稻品种,产量增幅分别为4.45～4.64、5.89～5.93和8.45～8.62 t hm＾-2。2000年以前的中粳稻品种产量表现为MN＞HN＞0N；2000年以后的超级稻品种则表现为HN＞MN＞0N。2000年以前的中粳稻品种在MN处理下具有较高群体质量指标（茎蘖成穗率、抽穗至成熟期的干物质积累、有效叶面积和高效叶面积指数、粒叶比、着粒密度、剑叶光合速率和根系氧化力）,2000年以后的超级稻品种则在高氮处理下具有较高的群体质量指标。这些结果表明,早期品种对氮肥响应较现代超级稻品种敏感,超级稻品种则在高氮水平下具有更高的产量。群体质量的改善是品种改良增加产量以及超级稻品种在高氮水平下物质生产和产量提高的重要原因。
