Improvement For Agronomic Traits Of Partial Waxy Wheat With Wx-D1 Gene Marker

Wheat (Triticum aestivum L.) is one of important food crops in the world. With improvement of the people's life and development of food industry, wheat flour quality become more and more important. Granule-bound starch synthase plays a key role in amylose synthesis. The amylose level can be reduced to zero through mutations of the waxy locus. In common wheat, there are three GBSSI genes (Wx-A1, Wx-B1, Wx-D1) which encode the granule-bound starch synthase. The waxy wheat does not contain all three waxy proteins, and the partial waxy wheat lacks either one or two of the waxy proteins. The partial waxy wheat is suitable for making dry white noodle, but there is not commercial waxy wheat in market due to agronomic traits of partial waxy wheat are too bad. To improve agronomic traits of partial waxy wheat, crossing between Chinese Baihuomai and wheat cultivars PH85-16, Jinan 17, and Yannong 15 was performed. The progeny plants were further backcrossed to these cultivars as recurrent parents for five generations. To get homozygous plants with the null allele at the Wx-D1 locus, self-pollination was carried out in the BC5F1 generation. Through another three generations, 13 partial waxy wheat lines were obtained, which had similar agronomic performance as their recurrent parents and carried the null allele at the Wx-D1 locus. In each generation, the Wx-D1 locus was identified by a PCR-based DNA marker and the agronomic traits were examined in progeny plants. The results from this study indicate that the use of backcrossing with a PCR-based DNA marker was useful in waxy wheat breeding. These partial waxy wheat lines can be used in field production.