Efficient Induction Of Intergeneric Chromosomal Translocations Through Pollen Irradiation Of Triticum Durum-Haynaldia Villosa Amphiploid

Haynaldia villosa （L.） Schur, a wild relative of common wheat, possesses many unique useful traits, such as resistances to powdery mildew, rust, take-all, eyespot, wheat streak mosaic virus, as well as drought and frost tolerance, good tiller ability, dense spike, polyanthus, and high protein content in kernels. Therefore, it is a potential gene resource for wheat improvement. Powdery mildew resistance gene Pm21 and wheat streak mosaic virus resistance gene Wssl have been transferred from H. villosa into common wheat. To localize, transfer and utilize other interested genes of H, villosa, the pollens of T. durum-H. villosa amphiploid were irradiated by 60Co-γ-rays and a mass of wheat-H, villosa intergeneric chromosomal translocations were induced in the present research. Effects of irradiation induction and transmission activities of different translocation types in different genetic backgrounds were investigated.chromosome or chromosome segments of H. villosa in common wheat background were identified by EST-STS molecular markers.1 Induction and transmission of wheat-H. villosa intergeneric chromosomal translocations To induce as many as wheat-H. villosa intergeneric translocation chromosomes involved in different chromosomes and chromosome segments of H. villosa, T. durum-H. villosa amphiploid was irradiated with 800,1200 and 1600 rad 60Co-y-rays, and pollens collected from the spikes 1,2 and 3 days after irradiation was pollinated to emasculated common wheat c.v. Chinese Spring. Wheat-H. villosa chromosome translocations were detected using genomic in situ hybridization technique in the M1 and their transmission was analyzed in BC1, BC2 and BC3 generations. The results showed that all the three dosages of irradiation treatments were highly efficient for inducing wheat-H. villosa translocations, and the produced M1 seeds were viable to germinate. The translocation induction efficiency and interstitial chromosome breakage-fusion frequency was increased as the irradiation dosage increased from 800 rad to 1 600 rad. Minor increase of translocation induction frequency was observed when using the pollen collected from the spikes one day than those 2 or 3 days after irradiation. More than 70%of the translations detected in the M1 generation could be transmitted to the BC1 through female gametes. Most of the translocations recovered in the BC1 generation could be recovered in the following generations. Various types of translocations showed relatively stable transmission ability in different genetic backgrounds with an order of ’whole arm translocation> small alien segment translocation> large alien segment translocation’, either through male or female gametes. Transmission ability through female gametes was generally higher than that through male gametes.2 Screening and Application of EST-based PCR Markers Specific to Individual Chromosomes of H villosaAll plants involved in wheat-H villosa translocation chromosomes were backcrossed with Chinese Spring, and some plants involved in single chromosome or chromosome segment of H. villosa in common wheat background have been developed. To identify H. villosa chromosomes or chromosome segments in these materials,240 STS primer pairs were designed based on the EST sequences of wheat and rice, and 34 of them could amplify specific polymorphic bands between Chinese Spring and H. villosa. These 34 STS primer pairs were further used for screening markers specific to individual chromosomes of H. villosa using 1V-7V disomic addition lines and their parents. The results showed that the marker CINAU32₃oo could be used for tracing chromosomeâ…£, CINAU33₂8o, CINAU34.510, CINAU35-1100 and CINAU37-400 for 2V, CINAU38-250 for 3V, CINAU39.950 and CINAU40.800 for 4V, CINAU41.745, CINAU42-1050 and CINAU43-245 for 5V, CINAU44-765 and CINAU45-495 for 7V. These EST-STS markers combined with the two 6V specific markers developed in our institute were used to identify the H. villosa chromosome and chromosome segments of backcrossed generations derived from pollen irradiation. A set of 1V-7V addition lines and 18 translocation chromosomes involved in different H. villosa chromosomes have been identified. Therefore, these chromosome-specific EST-STS markers could be used to detect chromosomes and chromosome segments of H. villosa in common wheat background.3 Development and characterization of Wheat-H villosa alien Chromosome Lines involved inâ…£Glu-Vl loci coding for high molecular weight glutenin subunits is located on long arm, and Glu-V3 loci coding for low molecular weight glutenin subunits and Gli-Vl loci coding gliadin （co-type and y-type） are located on short arm of chromosome IV. Higher seed protein concentration and SDS-sedimentation value were found in addition or substitution lines of 1V in Chinese Spring background than those in Chinese Spring. The development of wheat-H.villosa alien chromosome lines involved in chromosome 1V is an efficient method for introducing high quality genes from 1V into common wheat and provide potential genetic resources for wheat quality improvement. Chromosome C-banding, fluorescence in situ hybridization, high molecular weight glutenin subunits combined with molecular marker analysis were applied to detect chromosome 1V and its structure aberrants in backcrossed generations derived from （Chinese Spring/T. durum-H. villosa amphiploid （irradiated by 60Co-γ-rays）//Chinese Spring）. Alien chromosome lines involved in 1V were identified from BC1F1 to BC1F3. Four variants with chromosome structure changes of 1V were identified in BC1F3 and BC2F1, including whole arm translocation 1VS·W, whole arm translocation W·1VL, monotelosomic 1VS and ditelosomic 1VL, they would be new germplasms for wheat breeding.