Lodging-Related Stalk Characteristics of Maize Varieties in China since the 1950s

Stalk lodging often limits maize (Zeamays L.) grain yield potential and also causes difficulties in harvest operations. Stalk characteristics [e.g., plant height, ear height, and rind puncture strength (RPS)] have close relationships with stalk lodging in maize. The objectives of this 2-yr field study were to (i) report the changes in stalk lodging in maize cultivars that were widely grown in China since the 1950s, (ii) examine the stalk morphological and mechanical properties of maize within this timeframe, and (iii) assess the stalk lodging and grain yield of maize populations as related to changes in their stalk traits. The results showed that stalk lodging decreased significantly with the year of maize cultivar release. There was marked genotypic variation in lodging-related morphological and mechanical traits. The grain yield, dry matter accumulation (DMA), harvest index (HI), length of the 13th and 14th internodes, RPS of the fourth internode, and bending strength of the first internode all significantly increased in more modern cultivars. Length of the fourth and fifth internodes clearly decreased with improved maize cultivars. Among these traits, DMA, HI, and the length of fifth and 13th internodes were closely related to lodging resistance. As a result of stepwise regression analysis, stalk lodging was determined to be partially affected by variability in ear height or ear ratio. There were no significant correlations between stalk mechanical traits and stalk lodging. Our results indicated that improving the lodging resistance of maize cultivars was not accomplished by intentionally selecting these characteristics in China.