烟草品种对马铃薯Y病毒抗性遗传分析

Genetic analysis of tobacco resistance to potato virus Y

选用6个对PVY抗性有差异的烟草品种,采用完全双列杂交方法,研究了烟草对PVYN抗性遗传规律。结果发现:烟草PVYN抗性符合加性-显性遗传模型。参试品种间一般配合力(GCA)和特殊配合力(SCA)存在极显著差异,V.SCR的GCA最高,其次是VAM,是对PVYN抗性的高值亲本,K326的GCA最低,其次是NC95,是对PVYN抗性的低值亲本。通过V.SCR×K326和VAM×TN86组合证明了V.SCR和VAM两个亲本的SCA均表现较高,有进一步研究利用的价值。参试品种的显性基因和隐性基因数量不同,V.SCR的抗性和NC95的感病性是由显性基因控制的,TN86的抗性和K326的感病性是由隐性基因控制的,环境对显性基因的表达有较大影响。狭义遗传力较高(h2N),2003年为81.7%,2004年为74.43%,表明抗性基因可以通过基因累加的方式在后代中表现出来,宜早代选择。

Genetic mechanism of tobacco resistance to PVY^N was studied with complete diallel mating design of 6 cultivars with varied resistance to PVY^N. Results showed that tobacco resistance to PVY^N was additive-dominant. Difference of general combining ability （GCA） and specific combining ability （SCA） among varieties were highly significant. V. SCR had the highest GCA, followed by VAM, which were the high-value parents for PVY^N resistant, while K326 had the lowest GCA, followed by NC95, which were the low-value parents. Crosses V. SCR × K326 and VAM × TN86 had high SCA and therefore have potential value for utilization . The number of dominant and recessive genes among varieties was different. The resistance of V. SCR and the susceptibility of NC95 were controlled by dominant genes, while the resistance of TN86 and the susceptibility of K326 were controlled by recessive genes. Environment had considerable effects on the expression of dominant genes. Narrow sense heritability was much higher （81.7 % in 2003,74.43 % in 2004） which indicated that the resistant genes could be expressed in offspring through gene accumulation so that early generation selection was more suitable.