Inducing Chromosome Translocations Between Wheat And Agropyron Cristatum By The Gametocidal Chromosome And Radiation

Grain number per spike is one of important yield traits in wheat. This study reported that new translocation lines contained Agronpyron 6P chromosome fragment with multiple grain number trait were developed on the basis of two kinds of means, i.e. the gametocidal chromosome and radiating cross seeds. The former method was completed by crossing wheat-Agronpyron 6P disomtic alien addition or substitution lines with Chinese Spring-2C (derived from Aegilops cylindrica with gametocidal chromosome). The latter was carried out by radiating hybrid progeny seeds of wheat-Agronpyron 6P disomtic alien addition line and common wheat varieties Gaocheng8901. The offspring plants with different P chromosomal segments in the progeny were screened by SSR and SCAR markers. Some new translocation lines with multiple grain number traits were identified on the basis of the morphologic traits and GISH analysis. In this study, these materials will be valuable for the wheat improvement and depicting the physical map of 6P chromosome of Agronpyron.We obtained 34 translocation plants contained Agronpyron 6P partial chromosome from 672 F2 plants derived from the cross of the Agronpyron 6P disomtic alien addition lines (4844-12) and the Chinese Spring-2C. GISH detection of root tip cells proved that these selected individuals carried Agronpyron 6P chromosome fragment. The result showed that 5.06% translocation plants were created by the gametocidal chromosome. Many different translocation plants were found. Some representative translocation types included the midest chromosome translocation, the end of chromosome translocation, and the full arm chromosome translocation. On the basic of analysis of GISH and FISH, we estimated that translocations took place between the chromosomes 5A, 3B (or 7B), 4B (or 5B), and 4D (or 5D) in wheat and Agronpyron 6P.We finally obtained 9 translocation plants from 236 M2 progenies by radiating cross seeds of wheat-Agronpyron 6P disomtic alien addition line and Gaocheng8901. Furtherly, we obtained 16 new translocations plants in 76 plants of M3 derived from 4 M2 translocation plants. These translocation types included three long arm translocation, one short arm translocation, ten long arm-short arm translocation, one end translocation and one internal insertion translocation. GISH and FISH analysis showed that a translocation plant is 1A/6P translocation.We also radiated the pollen of Agronpyron 6P disomtic substitution lines and pollinated to common wheat Fukuho in order to obtain translocation material. By GISH and FISH detection of pollen mother cells of these F2 plants, we obtained one (3.70%) internal insertion translocation plants from 27 plants of M2 plants. Moreover, 41 (69.5%) translocation plants were observed from the 59 M3 plants, including 2 homozygous translocation lines, 5 heterozygous translocation lines, and 34 other translocation lines with one or two whole P chromosomes.The results of GISH and FISH suggested that these translocation lines occured between Agronpyron 6P and wheat chromosome 1A.Another 40 plants derived of the gametocidal chromosome, could not been detected by GISH, but proved to be contain Agronpyron 6P chromosome fragments by means of molecular mark. We guessed that these plants would have been the introgression or translocation materials containing small chromosome segment from Agropyron cristatum 6P chromosome. Finally, thirteen deletion lines congtaining different chromosomal segments of 6P were obtained in this study.