不同秋眠型紫花苜蓿春播短期栽培产量的差异及与地上部分枝的关系

摘要

试验选用7个秋眠、半秋眠和非秋眠型紫花苜蓿(Medicago sativa)品种,在南京地区进行春播仅刈割两茬的短期栽培条件下,研究不同秋眠型紫花苜蓿品种产量的差异及与分枝生长和类型的关系.结果表明:春播第一茬,非秋眠型紫花苜蓿的干物质产量显著高于秋眠型紫花苜蓿;第二茬品种间的干物质产量无显著差异;综合两茬来看,秋眠级高的品种其干物质产量依然存在优势.根颈分枝是决定紫花苜蓿产量的主要分枝类型.第一茬中,根颈分枝对产量的贡献率占绝对的主导地位,达到94.41％～96.01％;第二茬中,茎分枝的比重有大幅上升,但仍未能成为决定第二茬产量的主要分枝类型.分枝重对紫花苜蓿产草量的影响大于分枝数,在选育紫花苜蓿品种时,分枝重应作为首要选择标准.%Seven alfalfa varieties varying in fall dormancy (FD) were used to compare the forage yield and the growth of shoots (crown shoots and axial shoots) under a short-term cultivation system in Nanjing.Alfalfa varieties were sown in spring and harvested twice.Results showed that dry matter yield (DMY) of non-dormant alfalfa varieties were significantly higher than that of dormant varieties at the 1st cut,while there were no significant differences in DMY among varieties at the 2nd cut.Alfalfa varieties with less FD could produce more DMY than varieties with higher FD across two harvests.Crown shoots of each variety contributed the major portion of DMY.The crown shoots account for 94.41％-96.01％ in DMY at the 1st cut.Although the proportion of axial shoots increased greatly at the 2nd cut,it did not exceed that of crown shoots yet.Dry weight of individual crown shoot (mass · shoot-1) was more important than dry weight of individual axial shoot (shoots · plant-1) for DMY.Mass · shoot-1 should be taken as the determining selection criteria for alfalfa breeders rather than shoots · plant-1.