| Rice is important for both food safety of a country and meet of people life. Therefore, yield combined quality breeding will become a main aspect of rice breeding. It has been proved that heterosis-utilization breeding was an efficient way for improving rice yield. Scented rice is one of a main food that people like, which makes the hybrid rice breeding become one of a trend of rice breeding. Although aromatic hybrid rice breeding has been carried out for about twenty years, the principle theory has not been systematically studied except several combinations had been bred. Germplasm, hybrid vigor ,heredity, combining ability and breeding were studied and the main results were followed.1. Appraisal of germplasms and heredity diversity of aromatic riceappraisal on restoring and maintainer relationship and agronomy economy characters showed that nineteen of them were maintainer lines , twelve of them were restoring lines and two of them were half restoring. According to this ,germplasms were classified into two types, that was maintainer lines and restoring lines(including half restoring lines). Analysis of the heredity variation showed that variation of them were higher than that of check, which showed that rice resources have abundant diversity and potential utility. Yield Components of aromatic rice has its characteristics. For maintainer lines (B), grain weights per hill (GW/H) was correlated to setting percentages (SP). For restoring lines (R), yield was significant correlation to SP. Bulk and ways of characters acting on yield were as following. For B, grains of spike (G/S) , grain density (GD) and length of spike (SL) have a role in direct and indirect actions. For R, SP and grains per spike (G/S) only have a role in direct actions. Thirty three materials were classified into 4 types analyzed by clustering. the main characteristics of the first type was big spike. In the second group it was high effective spike and setting percentages. In the third integrate agronomic character were better. While bigger spikes, fewer spikes and lower 1000-grain-weights (TGW) was in the fourth group The results of SSR markers analysis showed that twenty four pairs primers out of 213 were polymorphism. Polymorphism of chromosome 7,8,11 were higher and least on chromosome9. seventy one isogenic spots were identified with twenty four pairs primers. Variation breadth of every isogene was 2-6, on average 2.96 isogenes were identified per pair primers. Variation breadth of primer information content (PIC) was 0.12.-0.672,on average 0.371 .The variation breadth was 0.120—0.672, on average 0.371.Variation frequency of isogene was 0.034-0.931,on average 0.388. Variation of Hs was 0.128-0.704 and 0.424 on average. Variation of Ht was 0.774-0.936 and 0.851 on average. From above we can see genetic diversity was abundant in aromatic rice. Germplasms were classified into three groups according to systematical clustering , which was consistent with begats and source. Therefore, heredity difference can be identified with SSR markers.2. Hybrid vigor analysis of crossing between aromatic rice (A/A) and between aromatic rice and non-aromatic rice (A/N) and its correlation to heredity distance.Results of hybrid vigor research showed that variation of the mean heterosis (MH) and heterosis over the better parent (HH) of GW/H in A/A was –30.26--89.53% and –-33.17-77.32%, respectively. On average it was 51.72% and 42.77%, which showed that the yield heterosis was bigger .While in A/N Variation of MH and HH was –7.51-37.87% and –17.52-30.80%, on average 16.21% and 7.53%. Variation was higher and best hybrids also has utilization value.Analysis on correlation between HH of GW/H and of other characteristics showed that G/S was significantly correlative to GW/H in A/A. Path Analysis in A/A showed that SP and G/S contributed more to yield, which was the direct action. Correlation between biomass to GW/H in A/N was significant at 1% level. Path analysis showed that biomass contributed more and harves... |
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