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The resistance expression of wheat-alien amphiploid is mostly dependent on genotype of wheat. The rust and powdery mildew resistance from S. cereale were quite easily expressed in its amphiploid with T. durum (Singh and Sethi 1994). The present results also showed that the stripe 'rust and powdery mildew resistance from S. africanum were expressed in this amphiploid. But the studies on another amphiploid involved different tetraploid wheat did not express the resistance from their donor S. africanum (Yang et al. unpublished). Therefore, on the utilization of alien resistance, the genotype of wheat should be considered in order to provide a wheat background for its resistance expression.

In addition, the different resistance genes existed in chromosomes of different rye-derived, such as gene Pm8 in 1R of Petkus rye, but Pm17 in that of Insave (Heun and Friebe 1990). S. africanum was a species different from cultivated rye. It is possible that powdery mildew or stripe rust resistance genes in S. africanum may be different from the genes in S. cereale. The amphiploid can be used as a new germplasm for improving the resistance of wheat.

The bread-making quality of Sichuan, China was very poor and the Glu-1 quality score for the composition of HMW-GS in Sichuan cultivars was rather low (Li and Wang 1998; Yen 1999). Moreover, stripe rust and powdery mildew resistance provided by 1RS/1BL translocation chromosome, widely existed in 70 percent of Sichuan wheat cultivars, was overcome (Chen and Ren 1996). Searching for novel germplasm resource was of importance for Sichuan wheat breeding. Based on the present study, the HMW-GS 2* of Glu-A1 and 23+18 of Glu-B1 in the amphiploid of T. durum cv. Ailanmai and S. africanum can be transferred to Sichuan wheat in order to increase the diversity for the composition of Glu-1 subunits in Sichuan released varieties. Meanwhile, the stripe rust and powdery mildew resistance of S. africanum in the amphiploid can also be utilized to improve the disease resistance to new races. Therefore, the amphiploid can serve as a new source for Sichuan wheat breeding for quality and resistance.

Acknowledgments

The authors are thankful to the National Natural Science Foundation of China and the Science and Technology Committee of Sichuan Province, China for their financial supports. We particularly thank Prof. Jiang HR for providing the seeds of amphiploid.


References

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