| China is very short of water and ranked as one of 13 the poorest countries of water by United Nations.Drought has been the main obstactal factor of infected rice yield. So we carry out the drought resistance appraisement index and drought resistance correlation character genetic studies of lowland rice and upland rice .It has very important theory and practice meaning to the lowland rice and upland rice 's drought resistance breeding and improve the yield.Polyethylene glycol (PEG) - 6000 were employed as osmotica for simulating water stress to study the germination characteristic of seed of 8 varieties, to establish the exact drought — resistance appraisemeort indexes The drought—resistance of 43 varieties was valued by repeat drought . 26 varieties were planted in paddy field and dry field to compare the difference of agriculture traits. According to griffing dialed cross design, 35 combination were got, to study combining ability and herittability of agriculture characters in dry land, in order to provide genetic germplasms and information. The main results were as follows:1. Germination rate after germinated 6 days in 20% PEG(20%/6d) had more variance range and coefficient of variation (CV) , and better proportion on varieties distributing than other's. 20%/6d was suit to value the ability of drought-resistance . Survivat rate of seedling after repeated drought was significantly correlated with the indexes of germination in osmotic stress and coleoptile length after germinated 8 days on 20% concentration of PEG,.2. Variance range of Survivat rate of seedling of upland rice varieties was 44.75—93.9%, average being 70.3%. Sequence according to value of livability (>75%) was handao 3, UND5, handao17 —0414, handao277, ningjing23, qiuguang, IRAT109, shuiniupehandao, UND6, han72, handao 4, handao297.These varieties can be utilized as drought—resistance resource.3. Sequence of traits which had prominence correlation with drought—resistance index (DRI) was grain weight per plant>grain number per spike >grain weight per spike>seed-straw ratio>number of spike per plant > seed setting percentage > spike length > highest number of stalks per plant. Sequence of traits which had prominence correlation with drought—resistance was grain weight per plant>grain number per spike>grain weight per spike>seed-straw ratio>seed setting percentage> number of spike per plant > spike length > thousand-grain weight > number of days from sowing to heading. Varieties that had stronger drought-resistance were handao 17-0414, hyandao277, hua73, hanhua3, UND4, handao4, handao5 according to DRI.4.Various characters were optimized by using the grey correlative analysis . Characters which had prominence correlation with drought—resistance index had grain weight per plant, grain weight perspike, grain number per spike , plant height, seed-straw ratio, seed setting percentage and thousand-grain weight.5. General combining ability (GCA) of Jingdao22,liaoyan241,D3,handao9,handao4 had more effect.They can be used as fertility genes.UND5/han64,Jiyujing/liaoyan241,Handao5/handao4 had better special combining ability on yield.6.The percentage of general combining ability (GCA) of plant height and thousand-grain weight was much more than that of special combining ability (SCA) ,and they were affected mainly by GCA. Additive effect and unadditive effect made similarly contribution on number of spike per plant, grain number per spike, total grain number per spike and seed setting percentage, the narrow heritabilities were 48.61 %~37.32%. Special combining ability (SCA) percentage of grain weight per plant was much more than GCA percentage, and unadditive effect was mainly function. Broad herittability and narrow heritability were contribution 66.93% and 19.00% respectively.7.To compare the genetic diversity of 55 origin different parents by 33 SSR marker showed that upland rice germplasm resourse was available in abundance. The upland rice varietals were divided into 5 types by 33 markers cluster analysis. |
