Relationship between Seedling Length and Plant Height and its Impact on the Selection of Short Plant in Rice

Abstract

A total of 95 and 94 varieties of rice were randomly selected in the first and the second crops of 1969 respectively for the calculation of correlation coefficients between seedling length and plant height. Most correlations reached the significant level, although the magnitude of the correlations decreased with the development of rice plants. Rice seedlings of three F2 populations were visually classified into tall, intermediate, and short groups before transplanting to find out whether rice seedlings of different seedling length would result in matured plant with different plant height. It was found that tall seedlings generally produced tall plants whereas short plants developed from short seedlings. The differences in mean seedling length as well as mean plant height were highly significant among selected populations. Genetic variances of plant height at maturing stage for selected F2 populations were considerably smaller than those of unselected F2 populations for all crosses in the first crop, whereas in the second crop, the reverse was generally true. Heritability percentages estimated for seedling length ranged from nil to 40.4%, varying with crosses and crops.

民國58年第1期作與第2期作分別選出95及94個水稻品種計算苗高與株高間之相關係數。就所得結果可知插秧前苗高與種植後各生育時期之株高成極顯著之正相關，惟其相關係數隨水稻之生長而逐漸遞減。 插秧前將水稻F2集團秧苗以目測方法依其長度區分為高、中、短三羣另以不加選拔者為對照觀察其移植後之稻株高度及其變異。初步結果顯示高苗常導致高株而短苗則多矮株。不同苗高羣間之苗高與株高差異多達極顯著水準。經過選拔之各羣，其第1期作成熟期株高遺傳變方較對照者為小，惟在第2期作則較對照者為大，F2集團苗高之遺傳力分佈在0與40.4%之間，其大小因組合及期作而異。