Study On The Utilization Of Heterosis With Genotypes In Japonica Rice

In order to strengthen the utilization of japonica heterosis, discuss the feasibility of F2generation or F3generation of using heterosis.6groups of F2generation of higher uniformityare selected from16group in different types of hybrid combinations, strong heterosis of hybridcombinations. Using uniformity analysis, heterosis analysis, correlation and grey correlationanalysis, genetic background analysis to study the uniformity, yield and quality traits of F2generation. The result shows that:1.The uniformity survey analysis shows that: The closer the agronomic traits between parentsare, the higher the uniformity of F2generation is. The phenotypic traits of the parent group, suchas plant type and ear type need to be consistent. High uniformity of F2generation is not strict，with plant height difference between parents.12cm is the permissible range. But the headingstage and plant height are interacting, if the plant height difference is12cm, parents’ headingstages need to keep consistent, if the plant height difference is less than12cm, the headingstages between the parents need to be within3d. No matter what mode the match group is, theF3generations will have a huge separation, making it difficult to be applied in production.2.The heterosis analysis shows that: The production of F2and F3generations declinessignificantly compared to F1generation, but the quality has improved, and the production of theF2generation keeps some advantages of heterosis. In production factors, single cavity effectivespike, and number recession of spike grain, is the main reason for the production decline of F2and F3generations compared to the F1.The result of parents correlation and regression analysisis that the single cavity effective spike and spike grain number condition of F2could bepredicted by analyzing the F1single cavity effective spike and spike grain number of parents.Therefore, the combinations of ears with more kernels, single cavity effective ear of the F1generation, can lower the recession of F2generation of heterosis.3.Canonical correlation analysis revealed that yield per spike and spike grain number in the F2generation is the main factor that affects the appearance quality and nutritional quality, namelythe smaller F2generation of grain is, the better the ear grain number and higher the rice qualitywill be.4.Output is the result of multiple factors interactions, high value parent single cavity yield hasthe greatest effect in the production of F1and F2generations of single cavity, but also attentionshould be paid to the low performance parents, too low performance will affect F1and F2 generation’s single cavity production performance. Yield of parents and the F1generation ofeffective ears to ear grain number and single cavity F2yield of single cavity effect sequence hasbeen in the top two, and spike grain number of F2generation is the most important factoraffecting the output of its own single cavity. Therefore, the parents having large ear grainnumbers should be paid more attention to, as this can not only improve the output of F2generation, but also improve its quality.5.Using66pairs of SSR primers to analyse genetic backgrounds of the21parent material andtwo contrasts (indica japonica).The results show that the21materials all belong to japonica, thecluster analysis result is the same with its pedigree relationship. The10combinations of F2which have more field separation and low uniformity have bigger genetic distance betweenparents compared to the6combinations with higher uniformity. So if a higher uniformity isdesired in F2generations, the genetic distance between their parents could not be too big;Genetic distance between parents could not explain the change of heterosis, further research isneeded.