Study On Relation Between Wheat Canopy Temperature And Traits Related To Yield In Grain Filling Stage

18 wheat germplasm resource having different canopy temperature were used as the experimental material to analysis dynamic changes of genetic variation of canopy temperature, the ration between canopy temperature and source-sink activity in in different grain-filling stage, to maken up canopy temperature synthetical indices—canopy temperature indexⅠ(CTIⅠ) and source-sink activity synthetical indices by analysis of principal component and test their relation by correlation analysis in grain-filling stage, to test relation between canopy temperature index and yield components by path analysis and decision analysis, to compare the activities of source, sink and flux between the cold typical wheat and the worm typical wheat, to analysis dynamic changes of relation between canopy temperature and kernel's filling index in grain filling stage, to make up anopy temperature synthetical indices—canopy temperature indexⅡ(CTIⅡ) from 21 days to 32 days after anthesis, and to estimate relative efficiency of indirect selection (REIS) of CTIⅡand REIS of comprehensive selection indexs conisisting of different number of quantitative characters for kernel's filling index. The results showed that:(1) Genetic parameters of canopy temperature were smaller and unstable before 21 days after anthesis, but were bigger and increased gradually after 21 days after anthesis. The reliability of selection was stronger and the anticipated effect of selection is better after 21 days after anthesis for canopy temperature.(2) The correlation coefficient with canopy temperature and source activity indexes increased gradually during grain-filling stage and were significant at 0.01 significant level in post-middle grain-filliing and late milk stage. The correlation coefficient between canopy temperature indexⅠ(CTIⅠ)and source activity synthetical indices were significant at 0.01 significant level.The cold typical wheat could maintain its superiority to the worm typical wheat in the contents of MDA, the contents of chlorophy ll, the activities of SPS, Net photosynthetic rate in flag leaves in post-middle grain-filliing and late milk stage.(3) The correlation coefficient between canopy temperature and sink activity indexes (the activities of adenosine diphosphorate glucose pyrophrylase (AGPP) is an exception) were significant at 0.05 significant level from post-middle grain-filling to late milk stage. The correlation coefficient between canopy temperature indexⅠ(CTIⅠ)and sink activity synthetical indices were significant at 0.05 significant level. The cold typical wheat could maintain its superiority to the worm typical wheat in the activities of SS, the activities of AGPP, the contents of soluble protein and the contents of soluble sugar in post-middle grain-filliing and late milk stage.(4) The correlation coefficient between canopy temperature indexⅠ(CTIⅠ)and Use efficientcy of soluble sugar potential in bleeding of spike neck(UESPBSN)in grains, bleeding potential of root, the numbers of lateral root , the weight of lateral root were significant at 0.05 significant level.(5) Direct path coefficient and correlation coefficient were significantly negative between canopy temperature indexⅠ(CTIⅠ) and kernel's filling index but were not significant between canopy temperature index and latent storage capacity.(6) The correlation coefficient of phenotype(pxy) and genetic factor(gxy), co-heritability(hxy), relative efficiency of indirect selection (REIS) between canopy temperature and kernel's filling inde(KFI) were small and unstable before 21 days after anthesis, but were big and increased gradually after 21 days after anthesis.(7) The correlation coefficient of phenotype(pxy) and genetic factor(gxy) between CTIⅡand kernel's filling inde(KFI) were significant at 0.01 significant level and contribution rate in correlated genetic variation (CRCGV) were 92.12%, the relative efficiency of indirect selection( REIS) of CTI was 83.76%.(8) The relative efficiency of indirect selection (REIS) of comprehensive selection indexs conisisting of CTIⅡ, blade angle of flag leaf, 1000-grain weight and anthesis was 101.30% for kernel's filling index, this comprehensive selection indexs was better.