Studies On The Yield And Its Formation Characteristics Of Different Hybrid Rice Seed Production Populations

Photosynthesis and the effective use of solar radiation are the foundation of crop yield formation,but until now there are few studies on the yield formation principle of hybrid rice seed production by the way of photosynthetic characteristics and solar radiation use mechanism.Using split plot experiment design,the field experiment of this study was conducted with fertilization model as main plot(M1:high-yielding seed production model,M2:high-yielding cultivation model) and Gibberellin concentration(The order from low to high is D1,D2,D3and D4successively) as spilt plot in Yong’ an Town Liuyang City in Hunan province and Jinyoul67and Ⅱ you416were chosen as the purpose varieties in spring and summer hybrid rice seed production respectively because their outcrossing seed-setting rate are relatively high. This study was aimed at the canopy photosynthetic characteristics and solar radiation use efficiency of different hybrid rice seed production population regulated by outcrossing cultivation and their effects on seed production yield and to find out the reason for the low yield and supply theoretical and technical support for enhancing the yield of hybrid rice seed production.The key outcomes are as follows.(1) There were no significant differences between the two fertilization models in the F1hybrid rice seed production in both Jinyou167and Ⅱ you416among different populations.There was a significant difference among the four Gibberellin concentrations in Spring seed production of Jinyoul67,and the yield of D2,D3and D4increased by36.4%、35.1%and45.8%than the control D1respectively,however there was significant difference only between D2,D4and D1in Summer seed production of Ⅱ you416and the yield of D2,D3and D4increased by66.1%and135.4%than the control D1respectively.The yield of different Gibberellin concentration populations under the same fertilization model increased with the increase of the concentration and M2D4always had the highest yield.(2) Analyzing from the yield component, the low outcrossing seed-setting rate was the main reason for the low yield.There were positive but not significant relationships between the yield and panicle per square meter,spikelet number per panicle,seed-setting rate and1000-grain weight in this study. (3) Analyzing from the formation of dry matter and its distribution characteristics,harvest index(HI) was the main reason that resulted in the yield and the yield increased with the increase of HI.There were significant differences between D2,D3,D4and the control Dlin both M1and M2in both Spring seed production of Jinyou167and Summer seed production of Ⅱ you416.There were no significant differences among D2,D3and D4and both M1and M2and the yield showed that D4>D2(or D3)>Dlin both M1and M2.(4) Analyzing from the use of solar radiation,there were no differences for radiation use efficiency(RUE) in different seed production populations before flowering,after flowering and in all growth stage.The intercept photosynthetically active radiation(RUE) of different seed production populations was high but the radiation use efficiency(RUE)was relatively low.There was a positive relationship between the yield and iPAR,RUE but not significant.The extreme high temperature in the year of2013resulted in a low outcrossing seed-setting rate,which had an effect on the result of the research about radiation use efficiency.The highest RUE of Spring seed production of Jinyou167and Summer seed production of Ⅱyou416were1.2g/MJ,1.0g/MJ respectively.A more further study related is needed to increases the outcrossing seed-setting rate and then make an relative conclusion.Above all,this study indicates that increasing harvest index(HI) under the foundation of increasing the biological yield is key factor to increase the yield of hybrid rice seed production,that is to say,increasing the transportation of dry matter to the grain. With regard to seed production populations.increasing the outcrossing rate can increase the sink capacity, which benefit for the increase of harvest index and the yield.