Analysis Of Heterosis Of Two-lines Hybrid Japonica Rice And Correlation Between Parents And Progenies

Two-lines hybrid japonica rice combinations from 5 japonica Photoperiod-sensitive Genic Male Sterile(PGMS) lines and 5 japonica restorers with the method of incomplete diallel crossing were used to analyze the heterosis of main characters of F1 combinations such as yield, rice quality, plant shape and growth duration, the correlation of Fl combinations and parents, and contributions of these characters to the yield. The results indicated: (1) two-line hybrid japonica rices had universal heterosis, in all characters single plant yield presented the strongest heterosis with 32. 21±14. 48% mid-parent heterosis and 10. 80±13. 73% heterobeltosis, the japonica hybrid rice with strong yield heterosis of 20%-30% higher than that of normal varieties could be bred through selection of parents; (2) head rice rate, chalky rice percentage and chalkiness score, the main characters of japonica hybrid rice quality, were dominantly influenced by female parents, female parents could interpret 56. 61% , 53. 83 %and 47. 21% of them respectively, so the breeding of PGMS lines with good rice quality was pivotal for the breeding of japonica hybrid rice with good rice quality; (3)there were no linearity correlations between the yield characters such as single plant yield, panicles, spikelets per panicle, seed setting rate and rice quality, the elite japonica hybrid rice with high yield and good rice quality could be bred through selection of combinations; (4) the chalky rice percentage and chalkiness score of combinations from a good rice quality parent and a bad rice quality parent presented negative heterosis, and the chalky rice percentage and chalkiness score of combinations from two bad rice quality parents showed positive heterosis, so one parent with good rice quality should be used in hybridization for a good rice quality combination. (5)in characters of Fl combinations, plant height showed heterobeltosis, spikelet length and growth duration were equal to the average of double parents, they only presented a few differences among combinations and could be true predicted according to perents.