用水稻田间杂蔸率估算种子纯度的一种新方法

水稻种子的纯度，必须通过抽穗后的表现进行鉴定。由于水稻种植中的基本苗数与蔸数是不一致的。因此以蔸为单位的田间纯度与以种粒为单位的种了纯度也是不一致的，现有方法是通过剥蔸计数估计种子纯度。这种方法费时费力且因样本少而不准确。对于由两本蔸和单本蔸组成的群体，推导了由杂蔸率g、全杂蔸率g1、半杂蔸率g2计算杂株率p的公式为：p＝0.5g1＋0.5g2＋1－√（g1＋0.5g2＋1）^2－4（g1＋0.5g2）]，并给出了判断是否存在三本及三本以以蔸的方法，证明了即使存在三本及三本以上蔸，该公式仍然能估计杂株率的上限值。

A New Method for Estimating Rice Seed Purity by The Use of Impure Rice Stubble Rate in Field

To judge the purity of rice seed in production must be done after rice tassel. There are differences between purity of seeds and stubbles because of the difference between seedlings and stubbles in field. The method used currently in practice is to take count of impurity seedlings in every stubble by cutting off it. It takes much time and energy and is inexact because of little samples. One formulae to compute the purity of seedlings(p), which can be used to estimate purity of seed, from the rate of impurity of stubble(g), of stubbles consisted of all-impure seedlings(g1), and of stubbles consisted of partially-impure seedlings(g2) was induced for the populations containing only one-seedling stubble and two-seedlings as:p＝0.5［g1＋0.5 g2＋1－（g1＋0.5 g2＋1）2－4（g1＋0.5 g2）］。 At the same time, the method to identify the populations containing multi-seedlings stubble was given. It was proved that the formulae can be used to estimate the maximum of seedling impurity when the populations contain multi-seedlings stubble.