| New varieties must have the distinctness, uniformity and stability, the stability and uniformity affected by the homozygous DNA locus ratio and the environment. The homozygous DNA locus was formed through the heterozygotes self-crosslinking, the homozygous DNA locus ratio will continue to increase with the generation increasing, and the stability and uniformity of their future generations will also improve. In China, years of wheat breeding for more than 5 years, in order to shorten breeding time, some wheat breeders used F4 lines as cultivars to carry out comparison tests and submit them to wheat cultivar regional tests. Therefore ten of F4 lines were employed to detect the homozygous DNA locus ratio and the uniformity as well as the stability of main agronomic traits in this study. The main results are as follows:1. The homozygous DNA locus ratio of 10 of F4 lines were 83.0– 94.8 %, the average was 90.0%. The ratios of their four parents were 98.5%, 98.2%, 97.9%, 95.3%, the average was 97.5%, the ratios higher than 95 %.2. The variation range of agronomic traits of F4 line BF-2003-82-17 were within the scope of the control cultivars by comparing with the control cultivars which the homozygous DNA locus ratio were higher than 95 %. The homozygous DNA locus ratio of BF2003-82-17 was 94.2%. It closed to 95%. Some agronomic traits of the other nine lines presented higher variation coefficient than that of the control cultivars, and some agronomic traits were still separating. It proves that the uniformity and stability of the most of F4 lines do not accord with the requirements yet. Only a few lines possess the uniformity and stability.So, it is possible to choose F4 lines with the uniformity and stability by detecting the homozygous DNA locus ratio and identifying the uniformity and stability of agronomic traits in the field, and to reach the purpose of reducing the breeding years. |
