| The crop genetic diversity has been eroded in the course of large-scale cultivated for single varieties. Genetic erosion not only limits further improvement of crop's yield and its ability resistance to environmental stresses, but also narrows the genetic bases. On the other hand, the loss of crop genetic resources, especially in wheat, becomes more and more serious. Wheat genetic resources are the original materials for wheat genetics and breeding research programs. Collection, conservation, evaluation and utilizations are the main works of wheat resources research. Of these works, the key work is evaluation. Tibet, the famous plateau agriculture region, had formed and conserved some specific wheat genetic resources under its unique natural environment. The objective of this study is to investigate the wheat genetic resources, collected from Tibet and conserved by the Triticeae Research Institute of Sichuan Agricultural University, by using agronomic characters, SDS-PAGE, A-PAGE and quality score of Glu-I locus.1. Higher genetic variations have been observed among the agronomic characters of Tibet wheat collections. The plant height varied from high to dwarf, the spikes per plant changed from 2 to 19.8, the spike length ranged from 5.7 to 19.2 cm, the spikelet numbers per spike were 17.5 to 29.8, the grains per spike varied from20.0 to 97.2, the 1000-grains weight changed from 8.74 to 50.0grams, and the grains weigh per spike ranged from 0.37 to 3.82 grams.2. On each character, there had some excellent accessions. Of these, 26 accessions were dwarf or semi-dwarf types. Thirty-eight accessions had more than 10 spikes per plant. Forty-eight accessions were mutisipikelet lines. For example, As 1243 had more grains per spike, Asl371 and Asl529 had higher 1000-grains weight, while Asl529 and As2064 had higher grains weight.3. Higher gliadin variations were detected among Tibetan wheat. There had 112 gliadin patterns among 128 Tibetan wheat collections. A total of 40 gliadin bands with different mobility could be separated in A-PAGE analysis, among which up to 90 percent bands were polymorphic. In a , p , r and " zones, the gliadin band combinations were different nearly among each accessions. Among these zones, b zone had the fewest band combinations, while w zone had the highest band combinations. There had 7 bands and 24 band combinations, 7 bands and 11 band combinations, 7 bands and 32 bands combinations, and 19 bands and 94 bands combinations in a , b , r and w zones, respectively. All of the Tibetan wheat collections could be divided into five groups based on cluster analysis of gliadin band data.4. There had 19 high-molecular-weight glutenin subunit combinations among 229 Tibetan wheat collections, among which Null, 7+8 and 2+12 was the most frequent combination. We found that some collections had the subunits of 17+18 or 5+10, which were associated with good baking quality. Furthermore, two novel high-molecular-weight glutenin subunits, tentative named 5* and 6*, were detected in Tibetan wheat collections.5. The quality scores of Tibet wheat collections were also calculated. On Glu-A1 locus, the highest score was 3, while the lowest was 1, with the majority of 1. On Glu-B1 locus, the highest score was 3, while the lowest was 1, with the majority of 3. On Glu-D1 locus, the highest score was 4, while the lowest was 2, with the majority of 2. The quality score of each Tibetan wheat collection varied from 4 to 10. The quality scores of 177 accessions (83.9%) were 6 or below, while there had 2 accessions (i.e. Asl531 and Asl772) with the highest score (i.e. 10). |
