[Developing waxy wheat with backcrossing approach and molecular markers-assisted selection].

Abstract

A series of Chinese Spring Wx loci near-isogenic lines were used to identify the specific bands of 6 STS markers and 1 CAPS marker of Wx genes. After optimizing PCR amplification and separation of PCR products, 3 co-dominant and dominant STS-markers were identified at the Wx-A1, Wx-D1 loci and Wx-B1 loci, respectively, which were used in molecular markers-assisted selection of waxy wheat in our breeding program. A cross between waxy wheat "98Y1441" and variety "Chuanyu 12" was made, and I2-KI dying method was used to select full waxy genotype individual from F2 seeds. The full waxy genotype individual was crossed with recurrent parent "Chuanyu 12". After 5 generations of self-cross and backcross, BC5F2 segregating population was obtained. Using the markers above, 8 Wx genotypes were developed from the BC5F2 population, which follows Mendelian segregation. Among them, there were 2 aabbdd waxy plants whose amylose content in the BC5F3 seeds were 1.81% and 0.82%, respectively. In addition, there were partial waxy plants (AAbbdd and aabbDD) whose amylose content in the BC5F3 seeds were 15.24 % and 17.57%, respectively. Most agricultural traits of the BC5F2 segregating population resembled those of the recurrent parent "Chuanyu 12", and superior to waxy wheat parent "98Y1441". This shows that backcross approach in combination with molecular markers-assisted selection of waxy genes is helpful to develop partial and full waxy wheat with good traits in the waxy wheat breeding program.