Changes in Agronomic Traits of Indica Hybrid Rice during Genetic Improvement
WANG Dan-ying1,XU Chun-mei1,YUAN Jiang1,2,WEI Xing-hua1,LIAO Xi-yuan1,ZHANG Xiu-fu1 1 .The State Key Laboratory of Rice Biology,China National Rice Research Institute,Hangzhou 310006;2.Key Laboratory of Southern Crop Physiology and Ecology,Ministry of Agriculture/Nanjing Agricultural University,Nanjing 210095
[Objective]The aim was to elucidate the changes of agronomical traits of indica hybrid rice during its genetic improvement.[Method]23 typical indica hybrid combinations cultivated in the middle and lower reaches of Yangtze River during the last 30 years were selected as experimental materials.All the hybrid rice combinations were grown in the same field;and then yield and morphological characters of single plant were compared;correlation and path analyses among agronomic characteristics were also conducted.[Result]During the 30 years of genetic improvement,the effective panicle number per plant was progressively decreased,which caused the decrease of grain yield and biomass per plant of hybrid rice combinations in spite of the slightly increased plant height,1 000-grain weight and number of grains per panicle.Although the transformation percentage of the matter in stem and sheath decreased after flowering,leave photosynthetic capacity after flowering was increased as panicle weight.Correlation and path analysis showed that although both biomass per plant and number of grains per panicle were significantly correlated with grain yield per plant,biomass per plant acted as the key factor affecting yield per plant.[Conclusion]It was suggested that in rice high yield cultivation,panicle number was as important as large panicle,and tillering ability should not be neglected in breeding.