英语语法分析

At natural condition rate of stigma exsertion has the positive proportion with seed rate.

在自然条件下，柱头外露率与异交结实率成正相关。

Objective】Stigma exsertion is one of the important traits which contribute to the efficient improrement of commercial seed production in hybrid rice.

目的 柱头外露是影响杂交水稻制种的一个重要性状。