基于InDel分子标记的籼粳杂交稻与粳粳杂交稻的杂种优势比较研究

【目的】随着籼粳杂交稻育种技术的发展与完善,直接利用籼粳亚种间杂种优势培育高产的水稻品种已成为可能。利用InDel分子标记及其成熟的技术,准确地分析品种的籼粳基因型频率、籼粳属性、品种类型与竞争优势水平,对籼粳杂交稻的育种与品种类别的甄别具有重要意义。【方法】征集浙江省多家育种单位培育的24个籼粳杂交组合和粳粳杂交组合,选用18对InDel分子标记引物,检测水稻样品在InDel位点上的粳型基因频率,判别参试品种的籼粳属性。采用Nei的方法求算参试品种的InDel遗传距离,用UPGMA法进行遗传相似性聚类,用SPSS 17.0统计分析软件对InDel条带赋值进行主成分分析,依据第一和第二主成分特征向量的平均分量值作平面散点图。调查或考察全生育期、株高、每穗总粒数、千粒重等10项主要农艺性状,测定小区籽粒产量及产量的竞争优势。测定InDel遗传距离与籼粳杂交组合和粳粳杂交组合竞争优势的相关性。【结果】18对InDel引物可扩增获得每个材料的籼稻特异带、粳稻特异带和籼粳杂合带型,经计算粳型基因频率,所有参试材料准确地判别出籼粳属性,并归为6类,其中12个为籼粳杂交组合,另外13个为粳粳杂交组合。经InDel标记的聚类分析,验证了上述判别的正确性。PCA分析把所有品种归入3个不重叠的区域,即籼稻区、典型粳稻与粳稻区、偏粳型与中间型区。籼粳杂交稻品种的2年小区籽粒产量分别比粳粳杂交稻品种增产12.47%和14.89%,表现十分明显的产量竞争优势。对比2类组合的10项农艺性状,籼粳杂交稻组的每穗总粒数2年分别比粳粳杂交稻品种增加32.0%和37.1%,每穗实粒数2年分别增加26.8%与34.4%,说明大穗是籼粳杂交稻增产的主要贡献因子。分析参试组合与嘉优2号的遗传距离(GD)及其各性状的竞争优势的相关性,结果粳粳杂交稻组合未发现有相关性,籼粳杂交稻表现为穗长和千粒重极显著呈正相关,着粒密度呈现为显著负相关。【结论】InDel分子标记技术可以有效地测定各种类型品种的粳型基因频率,并判别参试品种的籼粳属性,甄别品种的类型。籼粳杂交稻籽粒产量的竞争优势十分明显,其主要贡献因子是较大的每穗粒数。

Comparison the Heterosis of Indica-Japonica Hybrids and Japonica-Japonica Hybrids Using InDel Markers

【Objective】With the development and improvement of breeding technology in indica-japonica hybrid rice, it has been possible to explore inter-subspecific heterosis directly to develop high-yielding rice varieties. It is highly significant to be able to detect gene frequencies of indica or japonica accurately, identify indica-japonica attributes and cultivar classification, and to predict competitive heterosis by genetic distance for indica-japonica hybrid rice breeding and cultivar classification using InDel molecular mark and sophisticated technology. 【Method】Twenty-four indica-japonica hybrids or japonica-japonica hybrids, recently bred by different breeding units in Zhejiang province, were collected to analyze using eighteen pairs of primers selected from the InDel molecular marker. The gene frequencies of japonica genomics were detected by the Wang’s reported method, and tested materials were judged for different attributes. Genetic distance (GD) among tested materials was assessed by InDel molecular markers using Nei’s calculation method.. The genetic similarity (GS) was assessed using UPGMA cluster analysis of genetic similarity. Principal component analyses (PCA) were conducted using SPSS 17.0 statistical analysis software to assign InDel bands, then, on the basis of the average values of the eigenvectors of the first and second principal components, a scatterplot was created. Ten agronomic important characteristics, i.e. period duration, plant height, spikelet number per panicle, seed setting, 1000-grain weight and grain weight per plots were investigated for analysis of competitive heterosis. The relationships of competitive heterosis of japonica- japonica hybridsor indica-japonica hybrids with GD values to control cultivar were determined. 【Result】Eighteen pair of InDel primers could amplify all materials to obtain special indica bands, japonica bands and indica-japonica hybrid bands. According to calculated frequencies of japonica genes, these materials were accurately judged different to have indica-japonica attributes, and were divided into six clusters, twelve hybrids belonging to indica-japonica hybrids, and another thirteen hybrids placed into japonica-japonica hybrids. Again, using cluster analysis of InDel markers, this distribution was verified. With the results of PCA analysis, we show that all varieties classify into three non-overlapping tzones, an indica zone, typical japonica -japonica zone, and a japonica cline-intermediate type zone. Comparison of the average of plot yields in two-year trials, we found that the yieldsof indica-japonica hybrids increased by 12.5% and 14.9% over that of japonica-japonica hybrids, expressing outstanding yield advantages. Upon analysis of ten agronomic characters between the two type hybrids, total spikelet numbers and fertile spikelet numbers of indica-japonica hybrids were significantly increased by about 30%. We suggest that the attribute of larger panicles is the major contribution factors to yield increases. After comparative analyses of the genetic distances (GD) relationship oftested varieties to the control Jiayou 2, we found no significant relations the group of japonica-japonica hybrids, whereas have most significant positive relations with traits of panicle length and 1000-grain weight, but has a significant negative relations with the grain density. 【Conclusion】Using InDel molecular mark technology is powerful and effective in its ability to detect gene frequencies of japonica in various types of cultivars, and to identify their indica-japonica attributes or classify their cultivar types. The indica-japonica hybrid rice expressed significant competitive heterosis in grain yield, the major contribution of heterosis was more spikelets per panicle.