Synthesis And Utilization Of T.turgidum-Ae. Umbellulata And T. Turgidum-Ae. Comosa Amphidiploids

Aegilops umbellulata and Ae. comosa are two important diploid species in Aegilops genus. The two species contain many disease and pest resistance genes including resistance to wheat stripe rust, powdery mildew, cereal aphids, and tolerance to salt stress as well as other valuable traits. T. turgidum-Aegilops amphidiploids could be produced by distantly hybridization of diploid Aegilops with T. turgidum. Further, amphidiploids were used as a bridge for indirectly transferring of beneficial genes/traits from diploid Aegilops into wheat and therefore enriching the genetic diversity of wheat. Some wheat derivatives were obtained by crossing and backcrossing of T. turgidum-Aegilops amphidiploids with hexaploid wheats. Major agronomic and morphological characters including thirteen traits of plant and seed morphology traits of amphidiploids were evaluated. Besides, cytological and SDS-PAGE analysis as well as genomic in situ hybridization (GISH) and fluorescence in situ hybridization (FISH) were also used for amphidiploids and their wheat derivatives. The main results were as follows:In this study, eight different T. turgidum-Aegilops amphidiploids were produced. The seed setting rates among seven T. turgidum-Ae. umbellulata amphidiploids in S1 were varied from 0.09% to 2.50%, however, they were significantly increased in S2, and were ranged from 42.70%-50.00%. The seed setting rates in different generations of T. turgidum-Ae. comosa amphidiploids PI 94668/PI 554419 were very similar to those of the T. turgidum-Ae. umbellulata amphidiploids. The seed setting rate in S1 was lower than those of the S2 and S3. Typically, the seed setting rates of S1, S2 and S3 were ranged from 0.09%-0.33%,5.64%-44.56%, and 10.36%-49.46%, respectively. The hybrid F1, selfed F2 and backcross BC1F1 between tetraploid wheat-Aegilops amphidiploids and common wheat were also produced. The seed setting rates of selfed F2 and BC1F1 were higher than those of the hybrid F1. Moreover, variation in seed setting rates among different backcrosses were determinded by hexaploid wheat parents used for backcross.Thirteen plant morphology and seed traits of eight T. turgidum-Aegilops amphidiploids were investigated. All of the plant morphology traits including plant height, spike length, awn length, and flag leaf length and width except for tiller numbers in T. turgidum-Aegilops amphidiploids were intermediated between tetraploid wheat and those of the diploid Aegilops parents and were very closer to tetraploid wheat. However, all of the seed traits including seed length and width, projection areas, perimeter and the grain weight in T. turgidum-Aegilops amphidiploids were larger than those of their parents.Similar results for these traits were obtained in T. turgidum-Ae. comosa amphidiploids PI 94668/PI 554419. Besides, tetraploid wheat-Aegilops amphidiploids showed better stripe rust resistance than those of their tetraploid wheat and Aegilops parents.Chromosome pairing of pollen mother cells (PMCs) at metaphase I and chromosome numbers in root tip cells of some T. turgidum-Aegilops amphidiploids were investigated. The results indicated that the chromosome configurations and numbers varied among and within T.turgidum-Ae. umbellulata amphidiploids. For example, the chromosome configurations of PMCs of T.turgidum-Ae. umbellulata amphidiploids in Si of Langdon/PI 554395, Langdon/PI 428569 and Langdon/PI 554416 were mainly contained more unialents and a few rod bivalents. Chromosome numbers in root tip cells of T.turgidum-Ae. comosa amphidiploids were varied in different plants either from the same generations of S2 and S3 or from different generations of S2 and S3. The PMCs configurations of T.turgidum-Ae. comosa amphidiploids contianed more unialents and ring bivalents, and less trivalent and tetravalent. The chromosomes configurations of wide hydridization crosses of wheat with T.turgidum-Ae. umbellulata amphidiploids in F2 (BU 1-3-1) and of wheat with T.turgidum-Ae. comosa amphidiploids in BC1F2 (BM-3-1-1) were 2 n=12.28 I+10.56 ? ring+3.74 ? rod+0.02 ? and 2 n=6.00 ?+7.76 ? ring+6.00 ? rod+0.24 ?+0.40 ?, respectively. These results suggested that the amphidiploids were genetically unstable.High molecular weight glutenin subunits (HMW-GS) compositions in some T. turgidum-Aegilops amphidiploids were detected. The results indicated that the HMW-GS from the tetraploid wheat and diploid Ae. umbellulata parents were introduced into T. turgidum-Ae. umbellulata amphidiploids in Si of Langdon/PI 554395, Langdon/PI 428569 and Langdon/PI 554416 and S2 of Langdon/PI 554395, PI 94668/PI 554395, PI 94668/Clae 29 and PI 94668/PI 554413, respectively. However, the HMW-GS in S2 of T. turgidum-Ae. comosa amphidiploids PI 94668/PI 554419 were not the same. For example, the offsprings of M-1-2 and M-3-1 in PI 94668/PI 554419 showed the same HMW-GS as their parents nevertheless novel HMW-GS differed from their parents were observed for offsprings of M-4-1.Complete T. turgidum-Ae. umbellulata amphidiploid plants with all of the chromsomes of both parents with 2n= 42 were detected in S2 of Langdon/PI 554395 and PI 94668/PI 554413 using fluorescence in situ hybridization (FISH). Among the S3 plants of T. turgidum-Ae. comosa amphidiploids, different numbers of Ae. comosa chromosomes were observed using genome in situ hybridization (GISH). FISH analysis showed that some Ae. comosa chromosomes were lost in different plants of amphidiploids, and the chromosomes of Ae. comosa lost faster than those of the tetraploid wheat chromosomes. The results also shown that the chromosomes of 1M and 7M had the higher missing frequencies than those of the other M chromosomes.