小麦航天诱变后代的条锈病抗性变异及选择效果研究

为明确小麦航天诱变后代条锈病抗性的变异和选择效果,在甘肃陇南用系谱法对8个小麦品种的诱变后代进行了研究。结果表明,兰天10号、兰天14号、兰天17号在SP1(诱变一代)和SP2(诱变二代),PASCAL和85-173-4在SP2的群体病谱均较原品种对照发生了不显著的变异,但它们在SP1和SP2都没有出现显著的条锈病抗性突变体;郑麦9023、陇原031和DORICO在SP2均出现了显著的条锈病抗性突变系且有分离现象。8个品种的SP2和SP3(诱变三代)共获得9个显著的条锈病抗性突变系和12个显著的非条锈病抗性突变系,其中15个突变系的后代都出现了条锈病抗性的分离和变异。经过4代的选择,证明感病品种在SP2出现的抗性不显著提高株系具有一定的选择可靠性,从郑麦9023和陇原031中分别获得了抗条锈、大粒和兼抗条锈、白粉病的优良突变系。这些结果表明,航天诱变小麦种子能够引起后代条锈病抗性的丰富变异;变异可能出现在SP1、SP2或以后世代;对于感病品种在SP2出现的抗性不显著提高株系可以进行选择;不论哪一方面性状的显著突变系,一般会随世代进展出现条锈病抗性的分离和变异,都应作为抗性选择的目标对象而注意保留。

Variation and Selection Effects of Resistance to Stripe Rust in the Progenies of Wheat Space Mutagenesis

To elucidate the characteristics of variation and selection effects on resistance to stripe rust in the progenies of wheat cultivars by space mutation,the variation of stripe rust resistance in progenies of eight space mutant cultivars were analyzed by pedigree selection method in Longnan of Gansu province.Few mutant plants with significant variation of resistance for stripe rust had been detected in generation SP1 and SP2 of cultivars Lantian 10,Lantian 14 and Lantian17,and in SP2 of 85-173-4 and PASCAL.In susceptible cultivars Zhengmai 9023,Longyuan 031 and DORICO,both mutant plants with high resistant and with severe susceptible to stripe rust were found in SP2.Nine mutant lines with high resistance to stripe rust and twelve mutant lines with significant variation in other agronomy traits had been selected in SP2 and SP3 of these eight cultivars,fifteen of the 21 mutant lines displayed variation and segregation in response to stripe rust in their generations.By a selection of four consecutive generations for mutant plants in the field,several elite mutant lines derived from Zhengmai 9023 and Longyuan 031 showing high resistance to stripe rust and to both stripe rust and powdery mildew,and large grain suggested that the diverse variation of stripe rust resistance can be induced randomly by space mutation as shown in plants of SP1,SP2 or other generations.The effective selection of resistance to stripe rust can be conducted in the SP2 plants of susceptible cultivars since the segregation of resistance occurred in this generation of mutant plants.In addition,particular attention should be given on those mutant plants with different types of traits,which displayed segregation and variation of stripe rust resistance in the next progenies.Space breeding can be a novel and effective approach to both wheat germplasm improvement and resistance breeding for wheat stripe rust.