Determination of Resistance to Lodging by Stem Strength in Wheat

<正> Stem strength affects directly the resistance of wheat plant to lodging. Unfortunately, the determination of the stem strength is not perfect for wheat breeding and genetics up to now. In this study a prostrate tester was engaged for testing the stem strength of 661 wheat varieties and of 1183 single plants from a F2 population. The results showed that the suitable time to determine the stem strength should be from milk stage to dough ripe stage. The stem strength at the maturity would decrease and it was not easy to distinguish the difference among the varieties. The single plant with a strong stem could be judged using the prostrate tester from the F2 population. By testing the stem strength and anatomic characters of 30 varieties, a significant negative relationship between the pith diameter of the upper internodes and the stem strength was observed. On the other hand, there was a significant positive relationship between the stem diameter of the lower internodes and stem strength. It was suggested t