采用主成分分析和逐步聚类分析法,对6月生百日青(Podocarpusne neriifolius)容器苗的苗木分级标准进行分析.结果表明,苗高和地径的累积贡献率为84.473％,是评价苗木质量分级的主导因子,利用苗高和地径2个质量指标,获得苗木3级分级标准,即Ⅰ级苗:苗高≥24.7 cm,地径≥0.31 cm;Ⅱ级苗:24.7 cm＞苗高≥17.9 cm,0.31 cm＞地径≥0.27 cm;Ⅲ级苗:苗高＜17.9 cm,地径＜0.27 cm.
Study on Container Seedling Grading of Podocarpus neriifolius
This paper studied the standard of seedling grading of six-month-old container seedling of Podocarpus neriifolius through the methods of principal component analysis and stepwise cluster analysis.The results showed that cumulative contribution rate of seedling height and ground diameter was as high as 84.473％,which was the leading factor of the evaluation of seedling quality grading.Based on the two quality indices of seedling height and ground diameter,the container seedlings were divided into three grades:Grade Ⅰ (seedling height ≥ 24.7 cm;ground diameter ≥ 0.31 cm),Grade l] (24.7 cm ＞ seedling height ≥ 17.9 cm;0.31 cm＞ ground diameter ≥ 0.27 cm),Grade Ⅲ (seedling height ＜17.9 cm;ground diameter ＜0.27 cm).
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