Genetic Diversity Analysis Of Tibet Hulless Barley Cultivars And Its Improvement

The genetic diversity is the base of crop genetic improvement, and is important to the efficient collection, conservation and utilization of crop germplasm resources. Barley is an annual plant, belonging to genus Hordeum, family Gramineae. It has about 30 species, among which only common barley (H.vulgare, L.) has cultivating value, including two cultured types, hulled barley and naked barley. Naked barley, or hulless barley, is very important crop in the area of Tibet, and has a pivotal role in the agricultural industry there. With the adjustment of industrial structure and improvement of people's living standard, Hulless Barley, by right of its universal use and excellent quality, is playing increasingly greater role. Study on the genetic diversity and improvement of hulless barley has great significance in sustainable development of its production.In this study, 56 barley (hulless barley) from different sources were tested, including 7 foreign varieties (2 from Israel, 3 from Australia, 1 from Japan, 1 from Czech), 18 from Institute of Crop Germplasm Resources, Chinese Academy of Agricultural Sciences, (ICGR, CAAS) 31 from Tibet. Using PCR with intron-splice junction primers and long random primers, and molecular markers with high/low-molecular-weight glutenin, combined with field investigation of agronomic characters, the genetic diversity of barley were analyzed by combination of molecular lever and phenotype. Main research results and discussions are as follows:1. The genetic diversity among hulless barley varieties in the major agricultural areas of Tibet were analyzed using PCR with intron-splice junction primers and long random primers. The result indicates that 39 distinct PCR bands in total are amplified using 5 primers selected, and 26 of them are polymorphic. Thus, rich differences are performed among the samples. The analysis of the results using related software, combined with that of main agronomic characters, shows that there are some diversities among those hulless barley cultivars, but in general, their genetic differences are less and the genetic distances are relatively narrow; and that the dendrogram obtained from cluster analysis could reflect the distribution and the geographic characteristics of those cultivars clearly. This indicates that molecular markers can reveal the relationship of genetic evolution among varieties. Hulless barley varieties from Tibet can be divided into 4 classes on the DNA level. 2. Protein level is important quality index of barley. Present study indicates that gliadin and glutenin exercise the biggest influence on the quality of barley. Study on the genetic diversity of 56 barley cultivars indicates that there is no difference in high-molecular-weight glutenin among these samples, but there are certain differences in low-molecular-weight glutenin. cluster analysis of the results indicates that the protein genetic similarity coefficient vary greatly, while the average value of that is little. Based on the cluster analysis, these samples can be divided into 5 classes on the protein level.3. Agronomic characters of barley varieties from different sources have been investigated, and comparative study of main agronomic characters between hulless harley and barley from other sources was also conducted. The result shows that there are significant differences between hulless barley and barley from other sources in six main agronomic characters, including plant type, tillering, ear numbers, stem length, ear length, and thousand seed weight, and that there are complements among some important agronomic characters, indicating that some main problems in hulless barley can be improved using barley from other sources. According to the result of field investigation, these barley varieties can be divided in to three classes. Most of foreign materials are in classâ… , most of hulless barley in classâ…¢, and both materials from ICGR and hulless barley possess a definite proportion in classâ…¡.4. According to the assumption and breeding objective of hulless barley, 1324, Xiyin 2, etc, were selected from the samples to hybridize with hulless barley from Tibet. 7 main agronomic characters of progeny population of parents and F1, including plant type, tillering, ear numbers, stem length, ear length, thousand seed weight, and photosynthetic efficiency, were investigated and analyzed systematically. The result shows that there are significant differences between hybrid progeny population and their corresponding parents and that hybrid progeny has strong heterosis.