Study On Combining Ability Of Seed Germination Rate And Seed Vigor Of Two-line Hybrid Rice

In this study,15 hybrid rice combinations crossed by 5 indica dual-purpose genic male sterile lines and 3 indica restorer lines obtained according to incomplete diallel design,and16 hybrid rice combinations crossed by 2 indica dual-purpose genic male sterile lines and 8indica restorer lines obtained according to incomplete diallel design and their parents were used as materials.The differences of seed germination rate and seed vigor between parents and tested combinations were analysed,and the changes of seed germination rate and seed vigor after storage 6 months were studied.The combining ability of germination rate and seed vigor was investigated.These results will provide a basis and reference for the application of 5 indica dual-purpose genic male sterile lines and 11 indica restorer lines and the breeding of high quality seed rice varieties.The main results are as follows:1.The seed of sterile line 967 S had strong dormancy,the seed of 545 S and 427 S had high vigor,and the seeds of 427 S,545S and 998 S had strong storage resistance and flooding ability.The seed of restorer line 4W0802 had strong dormancy.The seed of restorer lines R018,4WH0818,X5H008,R1998,R161 and R751 had strong storage capacity.The seed of restorer lines R018,R028,7W749 and R751 had strong storage capacity and resistance to flooding.2.The dormancy of hybrid combination seeds was not strong.The 12 hybrid combinations of 234S/R018,427S/R018,545S/R028,967S/R909,998S/R018,998S/R909,998S/4W0802,998S/4WH0818,998S/X5H008,998S/R161,998S/R1998 and 998S/R751 had good storage capacity and high vigor.The 9 hybrid combinations of 234S/R909,967S/R909,427S/R018,998S/R018,998S/4W0802,998S/4WH0818,998S/4WH0818,998S/X5H008,998S/R161 and 998S/R751 had strong resistance to flooding flood resistance and high vigor.3.There was a good correlation between seed germination rate and seed vigor under standard germination test and artificial accelerated aging test and submerged germination test,and there was also a good correlation between seed germination rate and seed vigor before and after storage.4.Combining ability analysis of seed germination rate and seed vigor under standard germination test,artificial accelerated aging test and submerged germination test showed that seed germination rate and seed vigor were mainly controlled by non-additive effect.5.The results showed that the sterile line 998 S was easy to breed hybrid combinations with better germination rate and vigor and storage capacity and resistance to flooding of seed.545 S was easy to breed hybrid combinations with better germination rate and storage capacity of seed.Sterile lines 427 S and 967 S were easy to breed hybrid combinations with better storage capacity and resistance to flooding of seed.Restorer lines R909,R018,4W0802,4WH0818 and X5H008 were easy to breed hybrid combinations with better germination rate and vigor and storage capacity and resistance to flooding of seed.6.The results of heterosis analysis showed that seed germination rate and vigor index of hybrid combination were easier to exceed the lower parent,but were difficult to exceed the higher parent.