| The main grain quality traits of rice were studied in thist experiment by using following two sets of materials:1) 36 hybrid combinations from six photothermo-sensitive genic male sterile lines(Hua884S,Hua885S,Hua886S,Hua893S,Hua328S and PA64S) and 6 restorer lines (Huahui2185,Huahui1035,Hua110,BR06,Hua190 and Huahui3hao) were obtained according to NCⅡdesign.Combining ability,heterosis and genetics characters of 11 related grain quality traits,as well as the correlation among these quality traits from hybrids and their parents were analysed;2) 90 hybrid combinations were made by using three photothermo-sensitive genic male sterile lines(Hua893S,PA64S and Hua888S) and 30 lines derived from BC2F8 of zhenshan 97×93113 Combining ability and heterosis of 11 related grain quality traits of parents and their hybrid combinations were analysed.The main results were as following:1.The brown rice rate(BR) and ratio of grain length to width(RLW) reached the 3rd national standard leve of high-quality rice for most hybrid combinations from the first set of materials,with 91.7%and 80.0%,respectively.About half of hybrids reached the national standard level for amylose content(AC) and gel consistency(GC) traits.But for Head rice percentage(HRP),Chalky rice rate(CR) and Chalkiness degrees(CD),few combinations could meet the national standard level.2.Different extent of positively or negatively competitive heterosis existed among these quality traits from hybrid combinations.Therein,competitive heterosis of CR was the highest,that of illed rice rate(MR) and BR followed CR,that of HRP varied for different combinationseffect.The results of over-parent heterosis showed that all of these quality traits of tested combinations were superior to their parent lines except for the chalkiness trait.3.Both the general combining ability(GCA) of parent lines and special combining ability (SCA) of hybrid combinations contributed to all of quality traits in hybrid combinations, but the effects of GCA and SCA were different among these traits c dominated by additive effects.4.The results of comprehensive evaluation for quality traits of these parent lines showed that Hua328S,Hua884S and Hua893S were excellent in above male sterile lines,Hua1108 and Huahui2185 were excellent among above restorer liness Some combinations with better quality traits could be otained by these identified parents.5.The quality traits of hybrid combinations had higher broad-sense heritability,and the narrow-sense heritability of that was relatively low.The narrow-sense heritability arrangements of these traits from maximum to minimum were AC,Grain length(GL), LWR,CD,Gelatinization temperature(GT),GC,Grain width(GW),CR,HRP,BR and MR. Therein AC,GL and LWR could be selected in early generation of tested combinations due to the higher narrow-sense heritability.6.These had some extent of correlation among grain quality traits of tested combinations. Positive correlations were tested between BRand MR,MR and HRP,GL and LWR,GW and chalkiness trait,HRP and AC,CR and CD,chalkiness trait and AC.Negative correlations between MR and chalkiness trait,HRP and chalkiness trait,GW and LWR, chalkiness trait and GC,CR and GT.And for GL and GC,correlationship varied from different combinations.7.Some extent of correlations existed among the quality and yield related traits.Among them,Plant height(PH) and CR,CD;Effective tillers(ET) and HRP;Panicle length(PL)and BR,MR;Grains per panicle(GP) and MR,HRP,GC;1000-grain weight(KGW) and GL,LWR,AC showed positive correlations,PH and HRP,GT;ET and CR;TL and CD,GT,AC;Total grains per panicle(TGP) and GL;GP and GL,CR,CD, AC;Seed-setting rate(SSR) and CR,CD and AC;KGW and GC;Yield per plant(YP) and CR,CD and AC showed negative correlations.8.The quality traits heritability of hybrid combinations were controlled by female and(or) male parents,GL,GT and AC were mainly controlled by both female and male parents, HRP,CR and CD were mainly controlled by female parents;BR,MR,GW,LWR and GC were mainly controlled by male parents.
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