Three indica restorer lines （Mianhui 725, Shuhui 527, Shuhui 881）, an American rice variety Lemont and a javanica rice variety Xiangdali were crossed with japonica Kitaake, and five F1 hybrids were obtained to study...Three indica restorer lines （Mianhui 725, Shuhui 527, Shuhui 881）, an American rice variety Lemont and a javanica rice variety Xiangdali were crossed with japonica Kitaake, and five F1 hybrids were obtained to study the photosynthetic and agronomic traits. The data on photosynthetic characteristics indicated that the net photosynthetic rate （Pn） of the five F1 hybrids was significantly higher than that of their parents （or one of them） under high photosynthetic flux density （PFD）; while the overall performance of hybrids was better than their respective parents in apparent quantum yield （AQY）, carboxylation efficiency （CE） and CO2 compensation point （CCP）. Moreover, the photosynthetic performance of the five F1 were different due to the variation in heredity and the typical indica-japonica hybrids, Mianhui 725/Kitaake and Shuhui 527/Kitaake, were better than the others on this aspect. The agronomic traits revealed that the five F1 exhibited different heterosis, with Shuhui 881/Kitaake the largest sink followed by Mianhui 725/Kitaake, Shuhui 527/Kitaake, Lemont/Kitaake and Xiangdali/Kitaake. The production potential of indica-japonica hybrids was higher than that of the other two hybrids, which was consistent with the performance of Pn. However, the superior trait of indica-japonica hybrids on sink size has not been fully turned into high yield because of abnormal seed setting. Therefore, attention should be paid to the proper genome coordination and appropriate genetic distance so as to achieve super high yielding.展开更多
In rice,the Yongyou series of Xian-Geng intersubspecific hybrids have excellent production performance,as shown by their extremely high yield.However,the mechanisms underlying the success of these rice hybrids are unc...In rice,the Yongyou series of Xian-Geng intersubspecific hybrids have excellent production performance,as shown by their extremely high yield.However,the mechanisms underlying the success of these rice hybrids are unclear.In this study,three F2 populations are generated from three Yongyou hybrids to determine the genetic basis of the extremely high yield of intersubspecific hybrids.Genome constitution analysis reveals that the female and male parental lines belong to the Geng and Xian subspecies,respectively,although introgression of 20%of the Xian ancestry and 14%of the Geng ancestry are observed.Twenty-five percent of the hybrid genomes carries homozygous Xian or Geng fragments,which harbors hybrid sterility genes such as Sd,Sc,f5,and q S12 and favorable alleles of key yield-related genes,including NAL1,Ghd7,and Ghd8.None of the parents carries the S5+killer of the S5 killer-protector system.Compatible allele combinations of hybrid sterility genes ensure the fertility of these intersubspecific hybrids and overcome the bottleneck in applying intersubspecific hybrids.Additive effects of favorable alleles of yield-related genes fixed in both parents enhances midparent values.Many QTLs for yield and its key component spikelets per panicle shows dominance and the net positive dominant effects lead to heterosis.These factors result in an extremely high yield of the hybrids.These findings will aid in the development of new intersubspecific rice hybrids with diverse genetic backgrounds.展开更多
文摘Three indica restorer lines （Mianhui 725, Shuhui 527, Shuhui 881）, an American rice variety Lemont and a javanica rice variety Xiangdali were crossed with japonica Kitaake, and five F1 hybrids were obtained to study the photosynthetic and agronomic traits. The data on photosynthetic characteristics indicated that the net photosynthetic rate （Pn） of the five F1 hybrids was significantly higher than that of their parents （or one of them） under high photosynthetic flux density （PFD）; while the overall performance of hybrids was better than their respective parents in apparent quantum yield （AQY）, carboxylation efficiency （CE） and CO2 compensation point （CCP）. Moreover, the photosynthetic performance of the five F1 were different due to the variation in heredity and the typical indica-japonica hybrids, Mianhui 725/Kitaake and Shuhui 527/Kitaake, were better than the others on this aspect. The agronomic traits revealed that the five F1 exhibited different heterosis, with Shuhui 881/Kitaake the largest sink followed by Mianhui 725/Kitaake, Shuhui 527/Kitaake, Lemont/Kitaake and Xiangdali/Kitaake. The production potential of indica-japonica hybrids was higher than that of the other two hybrids, which was consistent with the performance of Pn. However, the superior trait of indica-japonica hybrids on sink size has not been fully turned into high yield because of abnormal seed setting. Therefore, attention should be paid to the proper genome coordination and appropriate genetic distance so as to achieve super high yielding.
基金partially supported by funds from the National Natural Science Foundation of China (32061143042, 31821005, 91935302)The National Key Research and Development Program of China(2016YFD0100802)
文摘In rice,the Yongyou series of Xian-Geng intersubspecific hybrids have excellent production performance,as shown by their extremely high yield.However,the mechanisms underlying the success of these rice hybrids are unclear.In this study,three F2 populations are generated from three Yongyou hybrids to determine the genetic basis of the extremely high yield of intersubspecific hybrids.Genome constitution analysis reveals that the female and male parental lines belong to the Geng and Xian subspecies,respectively,although introgression of 20%of the Xian ancestry and 14%of the Geng ancestry are observed.Twenty-five percent of the hybrid genomes carries homozygous Xian or Geng fragments,which harbors hybrid sterility genes such as Sd,Sc,f5,and q S12 and favorable alleles of key yield-related genes,including NAL1,Ghd7,and Ghd8.None of the parents carries the S5+killer of the S5 killer-protector system.Compatible allele combinations of hybrid sterility genes ensure the fertility of these intersubspecific hybrids and overcome the bottleneck in applying intersubspecific hybrids.Additive effects of favorable alleles of yield-related genes fixed in both parents enhances midparent values.Many QTLs for yield and its key component spikelets per panicle shows dominance and the net positive dominant effects lead to heterosis.These factors result in an extremely high yield of the hybrids.These findings will aid in the development of new intersubspecific rice hybrids with diverse genetic backgrounds.
