Abstract:

In this research an F₄ inbred line of Chinese milk vetch was constructed using Minzi No.7 milk vetch （Astragalus sinicus） as the female parent and the variety Xinyang as the male parent. For 18 strains in this population， the agronomic traits and nutrient absorption status were evaluated in a pot experiment at the full flowering stage， in order to use the results as a reference for screening superior milk vetch strains. Differences between plant strains were found. Correlation analysis showed that fresh weight， dry weight and accumulation of nitrogen， phosphorus and kalium were highly correlated， and were drivers of plant nutrient absorption， while plant height， branch number and leaf number were important factors affecting the fresh weight and dry weight of the plant. Principal component analysis showed that the main indexes such as shoot fresh and dry weights， and accumulation of nitrogen， phosphorus and kalium in the shoots could be used as indexes of Chinese milk vetch performance. In cluster analysis with the distance coefficient d=25， the 18 tested strains could be classified into three groups， of which Group Ⅰ had 4 strains （m83xzh-1-4-4， m83xzh-1-4-6， m83xzh-1-4-8， and m83xzh-1-4-13） with excellent multivariate trait scores. The best performing Chinese milk vetch strain in this evaluation was m83xzh-1-4-4. For this strain， the total plant nitrogen， phosphorus and kalium nutrient accumulation， accumulation of phosphorus and kalium in the shoots and accumulation of nitrogen and kalium in the roots were highest among the18 strains tested and were 11.00 mg·pot^-1， 145.18 mg·pot^-1， 22.15 mg·pot^-1 and 15.27 mg·pot^-1， respectively. The herbage fresh yield of m83xzh-1-4-4 was 44.63 g·pot^-1 and ranked second among the 18 strains tested. This study provides technical data which may be useful in future breeding work to develop new milk vetch varieties.

Key words: Chinese milk vetch, strains, nutrient absorption, cluster analysis