Effects of different mechanical direct seeding methods on grain yield and lodging resistance of early indica rice in South China

Direct seeding of rice has become a main planting method due to the low labor input and high economic benefit in South China. Dry direct seeding (DDS) has been widely used for single-season rice planting establishment. However, few studies have examined the performance of early-season indica rice under mechanical dry direct seeding. A two-year field experiment was conducted with two indica rice cultivars (i.e., Zhongjiazao 17 and Zhuliangyou 819) to study lodging characteristics and grain yield formation under DDS, flooded direct seeding (FDS) and wet direct seeding (WDS) patterns. The results showed that the annual grain yield in DDS was higher by 14.42–26.34% for cultivar ZLY819 and 6.64–24.58% for cultivar ZJZ17 than in WDS and FDS, respectively, and these increases were mainly attributed to the improvement of the panicles. The DDS pattern significantly increased the seedling emergence rate of early indica rice cultivars, and increased total dry weight and crop growth rate. Meanwhile, shorter basal internodes, better stem diameter and stem wall thickness and lower lodging index were found in DDS in contrast to FDS and WDS. In particular, DDS improved the stem lodging resistance. Our results suggested that the appropriate direct seeding method was beneficial for improving the grain yield and lodging resistance of early indica rice.