Creation and Genetic Analysis of a Male Sterility Mutant in Panicum miliaceum

Heterosis plays an important role in the development of new crop varieties with high-yielding, good-quality and biotic/abiotic stresses while male sterile line de- velopment is the key step to determine the success of heterosis utilization. A male sterile mutant, M207A was created in proso millet （Panicum mi/iaceurn, 2n=4x=36） for the first time using 60Co-y ray mutagenesis. Fertility identification and genetic analysis were carried out to characterize the mutant for its possible use for hetero- sis utilization in proso millet. First the sterility was investigated using both field sur- vey and indoor pollen microscopy identification. Then Pollinated by normal fertile proso millet cultivars, F1 and F2 populations from the mutant were obtained. Mean- while primary genetic analysis was also conducted using above populations in dif- ferent experimental sites, seasons and years. The results showed that the male sterile plant exhibited closed glumes, browning and dry anthers with few normal pollens. The sterility was stable and sterility rate was above 95% on average. The segregation ratio of fertile to sterile plants was 35：1 in the fertile selfing F2 popula- tion indicating that the mutant was a genic male sterility belonging to a pollen-less type controlled by a single recessive gene. The creation of the mutant, M207A can play a key role for heterosis utilization in proso millet.

Effects of Mutation and Hybridization on Breeding of Super High Yield Wheat Varieties

In order to develop high quality wheat varieties with super high yield, a theory which improved the genetic difference between parents by performing radi- ation mutation on them to enhance heterosis was proposed. The dry seeds treated and planted last year were radiated frequently by X- ray from 2003 to 2004. Then the dry seeds were radiated by high energy X ray combined with nuclear magnetic resonance from 2005 to 2007. We have treated the dry seeds repeatedly for 3 years and gained a variety of aberrant plants. These mutants were used as parents that were hybridized with the best plants in field. It was shown that a lot of mutant plants appeared in the f＇llial generations. After that, we selected big grains and super big grains among them. The result showed that, middle stem plants with big grains and low stem plants with big grains appeared. This phenomenon might be due to the breakthrough of linkage relationship between big grain trait and high stem trait. With the technique practice and materials, the new thoughts and methods were provided for induction and utilization of heterosis of wheat, which created a va- riety of seed selection and breeding materials for breeding super wheat varieties.