Production And Identification Of Wheat-Agropyron Cristatum 7P Translocation Lines

There were many desirable traits in wheat-Agropyron cristatum 7P disomic addition line Ⅱ-5-1, which can be used for wheat improvement. In order to introduce the elite genes from A. cristatum to wheat. Wheat-A. cristatum 7P translocation lines were produced by irradiation. GISH, FISH and molecular marker analysis were performed to identify these translocation lines and deletion lines. Genetic effects of 7P chromosome was evaluated by analyzing agronomic traits of translocation and deletion lines.The translocation lines got in this study were not only valuable materials in basic study but also excellent germplasm resources in wheat breeding.1. Several agronomic traits of wheat-A. cristatum 7P disomic addition line Ⅱ-5-1 were evaluated. It was found that Ⅱ-5-1 possessed following desirable traits compared to wheat Fukuho: higher thousand-grain weight, smaller flag leaf and higher drought tolerance, which Indicated that there may be genes controlling high thousand-grain weight, small flag leaves and drought tolerance in 7P chromosome.2. To introduce the desirable genes of 7P chromosomes into common wheat, Wheat-A. cristatum 7P chromosome translocation lines were induced by irradiation. 14 plants carrying 7P translocated chromosomes were identified by GISH in M1 and M1BC1 generations. Then 25 different types of translocation lines were identified by screening of offspring, including 2 whole-arm translocation, 10 small fragmental translocation line, 3 intercalary translocation lines, 9 large fragmental translocation lines and 1 intercalary + small fragmental translocation line. 25 translocation lines were identified by sequential GISH/FISH, showed that the translocation lines were translocated onto 13 chromosomes of three wheat genomes, including 2A, 3A, 4A, 5A, 7A, 3B, 5B, 7B, 2D, 3D, 4D, 6D and 7D. 5 different types of deletion lines were also produced.3. 55 STS markers specific to A. cristatum 7P chromosome were mapped on the different chromosomal regions, dividing 7P chromosome into 15 chromosomal bins. Seven and eight chromosomal bins were located on 7PS and 7PL, respectively, constructing the physical map of A. cristatum 7P chromosome. Based on the physical map of 7P chromosome, specific chromosomal bins included in each of the 18 translocation and three deletion lines were explored. Three translocation lines(S1-7, S4-7, and S5-7) only contained the whole or partial of 7PS1-7, and six translocation lines(L1-8, L4-8, L4-8, L5-8, L6-8, and L8) contained the whole or partial of 7PL1-8. Two intercalary translocation lines(S2-4 and L4-6) contain partial of 7PS1-7 and 7PL1-8, respectively. Four translocation lines(S1-7+L1-7, S1-7+L1-5, S1-7+L1-4, and S1-7+L1) contained the whole 7PS1-7 and partial of 7PL1-8, while three translocation lines(S1-6+S1-8, S1-3+L1-8, and S1-2+L1-8) contained the whole 7PL1-8 and partial of 7PS1-7. Besides, it’s clear that the deletion line 45b-6 included the whole 7PL1-8 and 7PS1-5, 7P-16-13 included the whole 7PS1-7 and 7PL1-2, 7P-13-21 only included the whole 7PS1-7.4. Three translocation lines and three deletion lines displayed higher thousand-grain weight than that of Fukuho. It is indicated that high thousand-grain weight genes were successfully imported into wheat and can expresse normally in wheat background. All these six lines contained the 7P chromosomal bins S1-3, suggesting that chromosomal bins S1-3 may contain the elite genes conferring high thousand-grain weight and grain length.