抗白粉病小麦-中间偃麦草染色体小片段易位系的选育与鉴定

 对从普通小麦与中间偃麦草杂交后代中选育的一个抗白粉病新品系(AF-1)进行了形态学、细胞学和原位杂交(GISH)鉴定。结果表明:AF-1具有与小麦亲本相似的农艺性状,根尖细胞染色体数目为2n=42,花粉母细胞减数分裂中期(PMCMI)染色体构型为2n=21Ⅱ,且未见其他结构变异,细胞学上十分稳定。GISH结果表明,AF-1为中间偃麦草与普通小麦的一个小片段易位系,易位点位于一对染色体臂的中部偏着丝粒的位置。结合抗病调查结果,推断该片段上携带了一个来自偃麦草的抗白粉病基因。该片段可能是在杂种早期世代通过部分同源染色体配对或者单价染色体错分裂而形成的。

Development and identification of a small-fragment-translocation line of wheat and Agropyrum intermedium resistant to powdery mildew

A stable small-fragment-translocation line, AF-1, derived from the progenies of common wheat variety Chuanmai 107 and Agropyrum intermedium was developed and identified by morphology, cytology, genome in situ hybridization (GISH) and powdery mildew resistance. The results indicated that AF-1, possessed similar agronomic traits with wheat parent Chuanmai 107, had the chromosome number of 2n=42 in root tip cells and chromosome configuration of 2n=21 Ⅱ at PMC MI, and was immune to predominant powdery mildew races in southwest of China. The results of GISH using the total genomic DNA of Pseudoroegneria and Ag. intermedium as probes, demonstrated that AF-1 was a small-fragment-translocation line. The translocation was found to be not involved the centromere, but occurred in the middle positions of chromosome arms on one pair of wheat chromosome. Genetic analysis showed that powdery mildew resistance gene of AF-1 most probably came from the genetic recombination through the homoeologous chromosomes pairing between wheat and Ag. intermedium or univalent undergoing misdivision at meiosis in early hybrid generations.