小麦Rht3基因遗传效应的研究

Studies on the Genetic Effects of Rht3 Gene in Wheat

利用具有株高梯度的4个小麦品种及其Rht3近等基因系和由它们配制的4个品种内杂种F_1,在4个品种的遗传背景下,比较Rht3基因在纯合、杂合及高秆等位基因rht3纯合时,小麦植株的株高,穗长、每穗粒数和千粒重等性状的差异。结果表明,除矮化株高外,Rht3基因具有增加穗长和每穗粒数、缩短穗颈长度、降低千粒重的遗传效应。4个品种平均,Rht3基因在杂合和纯合时,比rht3纯合时,每穗粒数分别增加21.90％和26.11％;千粒重分别降低14.9％和29.04％;株高分别降低26.69％和45.14％。此外,Rht3基因在矮化株高的同时还缩短胚芽鞘和第一叶长度,并且胚芽鞘和第一叶长度的缩短幅度与株高的矮化幅度呈显著正相关。文章进一步讨论了Rht3基因在杂种小麦育种中的应用前景。

Four wheat varieties were each hybridized with their Rht3 near-isdgenic lines and each formed three lines which had near-isogenic background but were in homozygous or heterozygous state of Rht3 and rht3 genes. The genetic effects of 'Tom Thumb' Rht3 dwarfing gene on plant height, ear length, grain number per ear and 1000-grain weight in a field trial of these near-isogenic lines were described. The homozygous Rht3 Rht3 and the heterozygous Rht3rht3 had the effects of reducing plant height by 45-14% and 26. 69% respectively. The Rht3 gene had pleiotropic effects such as increasing ear length and grain number per ear, shortening the length of peduncle, coleoptile and first leaf and reducing grain weight. Averaged over the four varieties, the Rht3 gene in homozygotic and heterozygotic states increased the grain number per ear by 26.11% and 21. 90% respectively, while decreased the 1000-grain weight by 29- 04% and 14- 9% respectively. This showed that when the Rht3 gene was used heterozygotically in hybrid wheat breeding, the increase in grain number per ear could make up the decrease in 1000-grain weight. Comparisons between the Rht3 near-isogenic lines and their tall parents showed that the effect of the Rht3 gene on shortening the coleoptile and the first leaf length was notably correlated with that on reducing the plant height. The prospect of the Rht3 gene used in semidwarf hybrid wheat breeding was discussed in the paper.