Coix has a long cultivation history as a minor crop in China, but many problems including unclear origin, chaos of species, loss and inaccurate use of germplasm resources exist in its research and production due to the lack of systematic study. In recent years, the importance of Coix has been realized with the exploration of its effects in treating and preventing cancer. The systematic study of Coix has met a superb development opportunity with the rapid development of biotechnology especially the deep-sequencing technique. Therefore, this paper presented here the current status of origin and evolution, classification, cytology and molecular biology progress of Coix, analyzed the ploidy of Coix and the genetic relationships with Zea, Sorghum and so on from the point of cytology, and then based on the molecular biology, analyzed the important significance of DNA molecular marker, genetic mapping and gene library in the research on identification of genetic relationship between species and genetic breeding, which could provide useful information for further Coix research.
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.
