Studies On Inheritance Of Starch Quality Traits In Wheat And Their Relations To Bread Baking Quality

245 wheat germplasm materials were used to study the correlation betweenamylose content, swelling power, falling number and Zeleny sedimentation value, agronomic traits. A set of diallel crosses involving 6 wheat parents, according to the model of Griffing Methods II ,was made to investigate the combining ability , heterossis, heritabiliry of amylose content and swelling power. 6 wheat cultivars growing in 4 locations were used to study the relation between amylose content, swelling power and environment.The results indicated that (1) the negative correlation between amylose content and Zeleny sedimentation value was significant; the positive correlation between swelling power and Zeleny sedimentation value extremely significant. The correlation above suggested starch properties affected baking quality. Because no significant correlation between falling number and Zeleny sedimentation could be observed, the falling number , which could not distinguish amylose from amylopectin in hydrolysis, should be investigated together with the bread score.(2) The amylose content and swelling power of domestic germplasm samples mainly distributed between 22% ~ 30% and 7~9 respectively, while the two indexes of the foreign germplasm mainly between 18% ~ 24% and 7~11 respectively. In terms of starch quality for baking bread, the foreign germplasm samples were better than their domestic counterparts.(3) Both amylose content and swelling power did not significantly correlate to such agronomic traits as plant height, spike length, spikelets number of single ear andthousand-kernel weight. It was possible to gain lines with low amylose content, high swelling power, high baking quality, desirable agronomic characters and high yield potential, so high yield and high quality could be harmoniously associated by crossing parents and selecting progeny correctly.(4) For amylose content and swelling power, the effect variance of the general combining ability and the special combining ability were both extremely significant., and the former was larger than the later, moreover, the order of the general combining effect value was in a same trend with the order of parents value. The heretability in the narrow sense of the two indexes were comparably low, so the selection should be conducted at high generation. It is evident that the average heterosis of amylose content was positive in effect, and the heredity of amylose content trended toward high value parent. Most of the average heterosis of swelling power was negative in effect, and the heredity of swelling power trended toward low value parent.(5) Both amylose content and swelling power were obviously affected by environment factors. The environmental variation of amylose content was close to the genetic variation, while the genetic variation, playing a main role in total variation of swelling power, was larger than the environmental variation. Accordingly the starch quality traits could be improved by breeding new varieties and providing desirable cultivation measures.(6) As the index of starch quality, swelling power was superior to amylose content by reason of its higher correlation to Zeleny sedimentation value andlower affection by environment.