矮败小麦在育种上的利用研究Ⅲ.矮败小麦育性的苗期预测

The utilization of the Aibai wheat in breeding Ⅲ. Prediction of plant fertility in seedling stage of Aibai wheat

矮败小麦的芽鞘长度与成株高度具有极显著的正相关关系（ｒ＝０．９５７６＊＊），短芽鞘苗成长为矮秆不育株，长芽鞘苗成长为高秆可育株，依自然群体芽鞘长度预测成株期育性的准确率为７２．２％．ＧＡ３处理可明显扩大矮败小麦幼苗在芽鞘长度、幼苗高度及叶长、叶色等形态上的差异，从而可将幼苗区分为ＧＡ３反应敏感型与不敏感型，２类幼苗比例为１１．ＧＡ３处理体积分数以１×１０－５～１×１０－４为宜，处理时期自萌芽期至二叶期均可．幼苗ＧＡ３反应与成株期株高相关，与育性分离结果基本一致．依ＧＡ３反应判别育性的准确率，室内试验为９５．５０％，田间试验达９５．１５％．较高的温度也可以扩大幼苗间的差异，在１６～３０℃范围内，随温度的升高，可育株的芽鞘长和苗高明显增加，而不育株则变化不大．较高温度还可增大ＧＡ３处理的效果，提高苗期预测育性的准确性．

There was a highly significant positive correlation between coleoptile length and culm height in the natural population of the Aibai wheat. The seedlings with short coleoptile would grow into sterile plants with short culm, whereas those with long coleoptile would grow into fertile ones with high culm. The accurate rate of fertility prediction was 72.2% according to coleoptile length.GA 3 treatment could enlarge the difference in coleoptile length, seedling height, leaf length and colours of individual seedlings in the natural population of the Aibai wheat. So that the sensitive or the insensitive to GA 3 could be easily classified. The ratio of 2 types of seedlings was 1∶1 (χ 2=0.077). GA 3 treatment had the same effect from germination to two leaf stage and volume fractions from 1×10 -5 to 1×10 -4 were advisable. Due to close relationship between GA 3 response in seedling stage and culm height in mature stage,the accurate rates in predicting fertile and sterile plants according to the responses of seedlings to GA 3 was 96.5% in the laboratory test, and 95.15% in the field experiment, respectively. High temperature could also enlarge the difference in coleoptile length and seedling height of individual seedlings. The coleoptile length and the seedling height of fertile plants rapidly increased with rising temperature ranged from 16 to 30℃, but those of sterile plants increased slightly. Moreover high temperature could enhance the effect of GA 3 on seedlings, thus achieving higher accuracy in predicting the plant fertility.The physiological reason of the response of seedlings to GA 3 was also presented.