Creation And Molecular Biological Identification Of Wheat-Thinopyrum Intermedium Translocation Line With Resistance To Wheat Rust

Wheat rust (yellow rust, stem rust and leaf rust caused by Puccinia striiformis f. sp. Tritici, Puccinia recondita f. sp. Titici and Puccinia graminis f. sp. Tritici respectively) is one of the most serious diseases in many regions of the world. Breeding and use of resistant cultivars is the most economical and effective approach to control this disease. The Thinopyrum intermedium with immune rust resistance, a wheat wild relative, is an important genes source for wheat improvement. In this study, a wheat- Thinopyrum intermedium alien translocation line with rust resistance C076 (Z4) was used to hybridize with common wheat. The HF1 regenerants were obtained through immature embryo culture. Two rust resistance translocation lines were isolated from the BCF3 offspring which was developed by successive backcross between HF1 and common wheat through identification of rust resistance and cytogenetics. The primarily results of GISH and C-banding showed that the translocation fragment was located on 7D or 2D chromosome. Two molecular markers specifically for Thinopyrum intermedium chromatin were also screened in these alien translocation lines by SSR and RAPD methods.1. In the two translocation lines with rust resistance developed from offspring of BCF3 by GISH, one was small homozygotic fragment translocation (WJS translocation); another was across translocation (JSW translocation).2. The results of rust resistance identification indicated that the small fragment translocation was stem rust and leaf rust resistant and the heterzygotic across translocation was yellow rust resistant.3. The chromosome composition of small fragment translocation was presumed through sequenced GISH, C-banding and SSR methods. The result showed that about 55% of region at terminational part of short arm belonged to 7AS chromosome of common wheat, about 55% of region at terminational part of long arm belonged to JS chromosome of intermediate thenoropy, remaining parts may belong to 7D or 2D chromosome of common wheat.4. Through RAPD analysis of small fragment translocation line and across translocation line, two molecular markers S-9 and S-3 specific for alien Thinopyrum intermedium chromatin were developed respectively from the two translocation lines. Another marker S-8 was shared by the two translocation lines.5. A molecular marker X-6 specific for alien Thinopyrum intermedium chromatin was also obtained from the small fragment translocation line.