我国常用杂交籼稻亲本杂种优势群的初步研究

根据已有的SSR分子标记对48个杂交籼稻亲本杂种优势群的划分结果,采用完全双列杂交设计和分群比较法研究了从不同类群选出的14个代表亲本相互杂交组合F1的杂种优势表现。结果表明,利用分子标记划分的4个杂种优势群及6个亚群之间存在遗传差异并构成28种可能的杂种优势模式。目前我国杂交籼稻杂种优势利用的主要模式如明恢63亚群×保持系群模式、两系恢复系亚群×保持系群模式仍然表现突出,而保持系群×温敏核雄性不育系群有可能成为新的杂种优势利用模式;两系恢复系和其他类型亲本杂交均能产生较强的杂种优势,定向改良后可能会提高籼稻杂种优势利用水平。

三类籼稻近亲型二元不育系的一般配合力研究

利用3个全同胞型二元不育系、11个回交型二元不育系和10个半同胞型二元不育系及其10个亲本纯合不育系,分别与南恢04、明恢86、辐恢838、先恢207和密阳46等5个恢复系按照NCⅡ交配设计配制了50个单交种和120个改良单交种,按随机区组的随机模型分析方法,对二元不育系主要性状进行了配合力分析。结果表明,所有性状的一般配合力方差和特殊配合力方差均达到了极显著水平。按照方差分析的分群比较法研究了三类二元不育系与纯合不育系单株产量及其构成因素的一般配合力差异,结果表明三类二元不育系单株产量和有效穗数的一般配合力都比纯合不育系极显著增加,回交型二元不育系和半同胞型二元不育系结实率的一般配合力也极显著高于纯合不育系,其他性状上二元不育系和纯合不育系没有明显差异。在水稻改良单交种育种中,以双亲具有近亲关系的二元不育系作母本进行适当配组,有可能选育出比相应单交种产量更高的水稻改良单交种。

Comparative Analysis of Improving Effects of 12 Maize Populations with Improved S_1 Selection Method

ln this study, 12 maize populations were improved with the improved S1 selection method, aiming to increase the improvement efficiency of maize popula-tions. The results showed that number of rows per spike, number of grains per row and 100-grain weight were the three important component traits of maize yield. The highest genetic increment was found in Mengqun 2, fol owed by Mengqun 4, Mengqun 1 and other 7 maize populations. Negative genetic increment was shown in Mengqun 3 and 3 introduced foreign maize populations. Some changes were shown in spikes, plant traits and genetic diversity of maize populations. Based on our results, we concluded that Mengqun 2, Mengqun 4, Zhongzong 7, Mengqun C and Mengqun A could be directly used for the line breeding by selfing for their higher genetic increment of yield and better improvement effects of other agricultural traits. Compared with these 5 populations, the improvement potential of other maize populations was limited for their lower genetic increment.