Abstract:

This research screened Elymus sibiricus germplasm in the Qinghai-Tibetan Plateau for anti-shattering traits and investigated the relationship between the degree of shattering and agronomic traits. Fifteen E. sibiricus germplasm lines collected in different regions of Qinghai were studied. Analysis of variance， correlation， principal component， regression and cluster analyses were carried out to evaluate the association between agronomic traits and the degree of shattering of E. sibiricus. The results showed that： 1） There were significant differences in natural shattering rate between the 15 E. sibiricus germplasm lines. A line numbered 17-124 had the most severe shattering， with an average rate of 56.92%. Lines numbered 17-064 and 17-050 had the strongest shattering resistance， with rates of 17.54% and 18.63%， respectively， and there was a large genetic difference between the germplasm lines. 2） Repeated measurements over time indicate that the shattering in each germplasm line indicates that the shattering rate continues to increase from the third day to the fifteenth day after the ‘milk’ stage of grain ripening， and there were extremely significant differences in shattering between maturity stages （P<0.01）. 3） There was a significant positive correlation （coefficient 0.437， P<0.01） between the number of spikelets and the shattering rate. There were also significant positive correlations between the fringe number， length of inflorescence， spikelet width and lemma length and shattering （P<0.05）， an extremely significant negative correlation between inflorescence width （P<0.01）， and a significant negative correlation between awn length and shattering （P<0.05）. Combining the results of principal component analysis and regression analysis， number of spikelets， awn length and inflorescence width were the main factors that affected the shattering rate. 4） The 15 germplasm lines were clustered into 4 groups by agronomic traits and shattering rate： Group Ⅰ included the genotypes which exhibited a high shattering rate averaging 41.24%， together with a high number of spikelets and seeds per inflorescence； Group Ⅱ and Group Ⅳ included genotypes with low shattering rates averaging only 18.63% and 17.54%， respectively. These can be used as candidate materials for screening of low-shattering germplasm； Group Ⅲ included genotypes with a high shattering rate averaging 42.41%， and with a high number of spikelets per spike， but with the least spikelets per inflorescence.

Key words: Qinghai-Tibet Plateau, Elymus sibiricus, seed shattering, agronomic traits