Identification And Genetic Analysis Of Common Wheat-Agropyron6P Small Segmental Translocation Lines

As an elite wild relative grass species of cultivate wheat, Agropyron cristatum(L.) Gaertn containslots of desirable genes for wheat improvement. According to the previous research in our laboratory,there are genes controlling multiple spikelets and florets on the A. cristatum6P chromosome. Therefore,it’s very important for wheat improvement to identify and characterize the translocation lines usingcytogenetic and molecular tools, as well as to study the genetic effects of these lines. In this study, thetranslocation progenies of the hybridization between the wheat-Agropyrum cristatum disomicsubstitution line4844-8and common wheat, and the disomic addition line4844-12and common wheat,were studied to uncover the genetic effects of the wheat-A. cristatum translocation lines. The results arewritten as below:1. An amount of44wheat-A. cristatum translocation lines were identified with GISH and werecatagorized into12different translocation types, according to the results. These include3differentwheat-A. cristatum homozygous intercalary translocation lines WATP6-29-7-11-2, WATP6-29-18-11-1,WATP6-32-1-2-10-1, and1homozygous distal translocation line WATP6-32-1-2-1-5, the plant numbersof them are WAT29-1, WAT29-19, WAT32-104and WAT32-151, subsequently.2.99EST-STS molecular markers were developed to efficiently trace the A. cristatum chromatinsby transcriptome sequencing and alignning. The control group for marker screening are A. cristatumZ559,4844-12and8different wheat cultivars. Among them,12markers were6P chromosome specificones. The markers were tested to locate on the0.00-0.32(1pair),0.32-0.69(3pairs),0.69-1.00(2pairs)deletion bins of the long arm respectively and the short arm(6pairs) of the6P chromosome. All of thesemarkers could be used as tools to identify the6P chromatin. Moreover, EST-STS molecular markersspecific to3small homozygous intercalary translocation lines(WAT29-1, WAT29-19, WAT32-104) and1homozygous distal translocation line(WAT32-151) were screened out separately.3. All of these translocation lines were grown in the field for the agronomical/biological screeningin2011and2012. The intercalary translocation line WAT32-104, with high thousand grain weight(TGW) was resistant to powdery mildew. The intercalary translocation line WAT29-19was excellent forits high grain number per spike (GNPS) and high TGW. The homozygous distal translocation lineWAT32-151had high spikelets number(SN). The excellent agronomic performances of these two linesindicated that they were elite genetic resources, and could be used to broaden the wheat genetic basis inthe future. This study confirmed that the compensate effects of small segmental translocation lines withlittle undesirable genes were good. They are the ideal materials of the development of translocationlines. These2lines value highly in wheat improvements of disease resistance, TGW and SN.In sum, the2wheat-A. cristatum homozygous intercalary translocation lines with elite agronomictraits which were identified in this study have great effect on the gene mining of the6P chromosome.12pairs of6P specific markers were screened out and located on the different deletion bins of the6Pchromosome, which paved the way to molecular screening of the progenies of the responsibletranslocation lines.