[Stem characteristics of different wheat varieties and its relationship with lodging-resistance.].

Taking four outstanding varieties Aikang 58, Zhoumai 18, Yumai 49 and Bainong 418 from Huanghuai wheat area as test objects, the lodging-resistance traits of different varieties at different growth stages were investigated by combining field and laboratory methods. The results showed that stem mechanical strength was at a high level between flowering and 20 days after flowering, declined significantly in 30 days after flowering. The lodging index was minimal in flowering period, maximal in 30 days after flowering, and was at an intermediate level in the other two periods. Correlation analysis showed that culm mechanical strength was significantly negatively correlated with the height of gravity, and significantly positively correlated with cellulose and lignin contents at the flowering, lodging index was significantly positively correlated with the internode length, plant height and height of gravity, but significantly negatively correlated with cellulose and lignin contents. Ten days and 20 days after flowering, the culm mechanical strength was negatively correlated with the internode length, plant height and height of gravity, and significantly positively correlated with stem diameter, cellulose content, hemicelluloses content and lignin content, while the lodging index was just the opposite. Thus, making lodging-resistance related stem characteristics at each stage clear, could provide a basis for breeding lodging-resistance and high yield varieties in Huanghuai wheat area.