苜蓿生长特性和产草量关系的研究

Forage yield component and growth characteristics of Medicago sativa

以来自北美、欧洲、澳洲和我国的84个苜蓿种质为材料,对苜蓿生长特性和产草量相关性状进行分析和评价。5年田间试验结果表明,在整个生长季苜蓿可以保持高的生长速率,刈割后苜蓿表现出不同的再生生长节律。第1次刈割后苜蓿的再生生长表现出先慢后快的生长节律;第2次刈割后苜蓿可以迅速再生,表现为先快后慢的生长节律。根据生长速度的快慢将不同苜蓿种质的生长能力分为快速生长、普通生长、慢速生长和生长不良4种类型。对苜蓿生产性能相关农艺性状进行主成分分析,苜蓿全年鲜草产量与第2次刈割时的生长高度之间的相关程度较高。5个入选因子主成分累积贡献率为81.132 0%,其中第1主成分为刈割因子,贡献率为46.389 0%,第2和第3主成分为分枝数因子和高度因子。第1次刈割的鲜草产量对全年的产草量贡献较大,以后2次刈割的产草量对全年产量的贡献逐次减小。

The levels of forage yield, growth and regrowth characteristic of 84 lines of Medicago sativa with different origins including domestic cultivares and some lines from South Australia, North America and Europe were assessed in a five-year field trial. M. sativa maintained a high rate of growth during the whole growing season, but cultivars had different regrowth rates after harvest cutting. M. sativa regrowth was initially slow after the first cutting then quickened. After the second cutting the growth rate was higher, and then slowed down. There were four types of M. sativa growth in different lines, growth rapidly, common growth, growth slowly and unchanged growth. Prineipol component analysis （PCA）on agronomic traits of M. sativa showed the high correlation between total fresh weight and growth height at the second cutting. The cumulative contribution of the first 5 factors was up to 81. 132 0%. The first component factor was the cutting factor and others were branch factor, plant height factor etc. The fresh weight of the first cutting accounted for the major share of the total yield, and later cuttings contributed less to the total field yield.