Tang ShuZhu

Variation and distribution of seed storage protein content and composition among different rice varieties.

The crude protein contents(PC) in 351 varieties were measured by near infrared spectroscopy(NIRS) and their distribution and classification were analyzed.The results showed that the average value of crude protein content in indica and japonica types were 13.2% and 12.2%,respectively,with an average of 12.42%.The ranges of those above were 10.8-16.8%,9.3-17.7%,and 9.3-17.7%,respectively.It elucidated that PC was higher in indica rice than that in japonica rice.The huge difference in ratios of varieties(lines) based on their PC showed the genetic disequilibrium between subspecies indica and japonica,for example,the ratio of japonica rice with low PC was eight times that of indica rice with low PC.According to the criterion classifying varieties with different protein contents,most of rice genotypes fell into the group with intermediate PC,and there was very small number of varieties with either high or low PC,especially with very high PC in japonica rice.However,we could find some extreme individuals whose PC were very high/low,such as those with high PC:forage rice,early maturity varieties and indica-japonica hybrid progenies close to indica in the subspecies of indica,or close to japonica in the subspecies of japonica;and those with low PC:some japonica rice(but the PC not low enough),some overseas germplasms in indica.Thus it was not impossible to find out extreme germplasms on PC from landrace,overseas germplasms or indica-japonica hybrid progenies etc.,which are fine basic materials in genetic and breeding research.From the results of SDS-PAGE analysis of the total seed storage proteins among some representative varieties,we could know that the seed storage protein composition was different among different types of rice genotypes.

Comparative study on breeding utilization characteristics of the isonuclear alloplasmic japonica CMS lines Liuqianxin A with four different cytoplasm sources.

A set of isonuclear alloplasmic japonica CMS lines Liuqianxin A,constructed with four different cytoplasm sources from Hainan Male Sterile Wild Rice (WA type),Hainan Red Awned Wild Rice (HL type),Hunan Chaling Wild Rice (CL type),and India Chinsurah Boro II (BT type),respectively,together with their maintainer line Liuqianxin B,were applied to study their male sterile stability,flowering habits,outcrossing rate,and restorable ability.The results showed:(1) Most pollen granules of BT,HL and CL Liuqianxin A were mainly stained-abortion,while those of WA Liuqianxin A were mainly typical-abortion.Selfed seed-setting rate of BT Liuqianxin A was 0.60%,which would cause application risk in agricultural production.There were no selfed seeds in HL and CL Liuqianxin A,indicating that sterility of them was better than that of BT type.(2) The length of 1st internode to the top was affected by the degree of abortive pollen,which influenced the plant height and the panicle exsertion (i.e.the length of panicle-neck above the sheath of flag leaf).Namely the more serious abortive degree,the shorter panicle exsertion.Therefore,panicle was enclosed within the sheath of the flag leaf in WA Liuqianxin A,not in BT,HL,and CL Liuqianxin A.(3) The flowering habits of WA Liuqianxin A presented as sporadic flowering,distinctly lagged flowering time and stretched flowering duration,and were the worst in the four type CMS lines,thus its outcrossing rate was lower.Flowering habits and outcrossing rate between HL,CL CMS lines and BT CMS lines were not significantly different.However it was better in HL,CL CMS lines than in WA CMS lines.(4) BT Liuqianxin A showed the best restorable characteristic,HL was a little worse than BT,WA was the worst.And japonica restorers for HL or CL CMS lines could be selected from the japonica restorers for BT CMS lines.HL,CL CMS lines balanced above contradictions well,so an idea of substituting HL,CL CMS lines partly for BT type was put forward,it can be used to solve the problems of single type sterile cytoplasm in current Japonica hybrid rice and fertility not stable in BT CMS lines.

Analysis of Characteristics and Heterosis of Three-Line Parents in Hybrid Japonica Rice

Sixteen representative varieties each for BT-type cytoplasmic-nucleic male sterility (CMS) lines,maintainers and restorers were collected respectively,and 229 hybrid combinations were developed in this study.Then the correlations between parents and progenies were analysed on the all traits.The main results were as follows: (1) Compared with the maintainers,the restorers had higher plant height,thicker stalk and bigger panicle.The latent storage capacity of the maintainers and restorers was about 30 g on an average,and the restorers had less tillers,lower seed setting rate and lower 1000-grain weigh,resulting in the lower yield per plant.The chalkiness degree of restorers was higher than that of maintainers,while the amylose content of restorers was significantly lower than that of maintainers.(2) The mid-parent heterosis of hybrid japonica rice was strong,while the over-parent heterosis of most characters was weak excepting the competitive advantage of growth vigor.The panicles of hybrid japonica rice were big,showing the positive heterosis,but the seed setting rate had a negative heterosis,which was the main limiting factor on the yield heterosis of hybrid japonica rice.(3) Analysis of the correlation between parents and their progenies indicated that the correlation between the character values of F1 combinations and this mid-parent values was the best.Comparatively,the correlations between CMS lines and F1 in heading date and total spikelets per panicle were significant,while the correlations of restorers and F1 in plant height,filled grains per panicle,seed setting rate,yield per plant and quality characters were significant.