The Sensitivity Of Pre-harvest Sprouting Of Wheat And Its Genetics Analysis

1. 25 wheat varieties, which were selected from the middle and lower reaches of the Yangtse River, were measured for the ratio of pre-harvest sprouting and grain germinating in 2000-2003 three consecutive growing seasons. Analysis of variance indicated that the sensitivities of pre-harvest sprouting and grain germinating on panicle be influenced by the length of rainy season and genetic background of the varieties.2. The detection of α-amylase in submerged wheat seeds indicated: α-amylase was accumulated along with the germination of the seeds. And it could not be used as the index of pre-harvest sprouting. It was also found that there was relationship between the glume packing extend and the sprouting. The tighter packed glume, the lower sprouting was. The gelatinization properties (RVA parameters) were also measured for the 25 wheat varieties and 42 F1 materials. It was found that some parameters had correlation with the ratio of pre-harvest sprouting including Peak Viscosity, Breakdown, Trough Viscosity, Final Viscosity, Setback and Peak Time.3. Two crosses were established and its 6 crossing generations PI,P2, F2,F2, B1, B2 were obtained. The cross I was formed with Zhongyoul6 as female parent, Zhen9523 as the male patent. And the second cross was done with 992803 asmaternal and the Su9356 as paternal. The genetic model analysis of 2 crosses showed that, characteristic of genetics for grain germination at mature period fitted well with the model of additive-dominance-epistasis. There were additive and dominant effects in 2 crosses. So some epistasis effects were eliminated, for their smaller or no significant effects. The genetics of grain sprouting had the phenomena of super-dominance.4. In this paper full-diallel crosses were carried out with 4 red and 3 white wheat varieties, which had different sensitivities of pre-harvest sprouting. The combining ability analysis of F showed that the pre-harvest sprouting of wheat was mainly controlled by additive, dominant and cytoplasmic effects, implying the sensitivity of pre-harvest sprouting could pass down to the offspring steadily. The broad and narrow heritabilities were all very high, which expressed that the pre-harvest sprouting was mostly influenced by genetic lactors, so it was possible to select objective materials in early generations in pre-harvest sprouting resistance breeding.