酥梨产量构成因素的通径分析

STUDIES ON PATH ANALYSIS OF THE FACTORS OF YIELD FORMING IN BAISU PEAR

两年定树调查测定44株次的酥梨产量及其相关的树高/冠径、花芽数、总果数、座果率、枝/果,叶面积系数、每果叶面积、平均单果重等8个性状。应用逐步回归法逐个别除对于产量没有显著线性效应的性状,得到包括总果数、每果叶面积和平均单果重在内的最优多元线性回归方程。再对入选的各个主要性状进行通径分析,明确其对产量构成的直接和间接效应。结果说明,提高酥梨单株产量。首先要具有一定的果量,其次是增加平均单果重,再次是维持叶面积与果实的适当比例。在树冠大小基本稳定的情形下,增加每果叶面积会造成果量减少而使产量下降,同时又可提高平均单果重而使产量上升。每果最佳叶面积应是提高平均单果重而使产量的上升量大于因果量减少而使产量的下降量,这样不仅可以增加产量,而且可提高果实的商品竞争力。

The yield of each of 22 trees and its 8 charactors in Baisu pear (P. bretschneideri Rehd), involving tree height/diameter of tree crown, flower bud number, total fruit number, percentage of fruit set, branche/fruit, coefficient of leaf area, leaf area/fruit, mean weight of fruit, were investigated and measured respectively in 1983 and 1984. After using the regression of eliminating the unremarkable indepent-variables one by one in stepwise regression, the optimally linear equation of multiple regression involving total fruit number, leaf area/fruit, mean weight of fruit, was abtained. Then, the direct and indirect effects of each main parameter selected on the formation of the yield were determined with path analysis. The results showed that for raising the yield of a single tree, there must befirst, the certain fruit number; secondly, an increase in the average weight of fruit; thirdly, the optimum ratio of leaf area to fruit. The increase of leaf area/fruit would cause the decrease of fruit number, thus making the yield reduced, at the same time, it would result in the growth of the average weight of fruit, thus making the yield increased, on condition that the volume of tree crown remaines steady. To a certain extent, increasing the mean weight of fruit not only makes the yield increased, but also promotes the competitiveness of marketable fruit.