Coix lacryma-jobi L. growth and yield response to different sowing dates in Sichuan China

Coix lacryma-jobi L., a potential energy source, is a very useful and productive grass. Although it is widely used in folk medicines for abdominal tumors, esophageal, gastrointestinal, lung cancers, various tumors, etc., its growth and yield response to different sowing dates has not been studied yet. In this study, three cultivars were selected and six sowing dates were designed to investigate the effects of the sowing time on its growth and yield in Sichuan China. Several agronomic characteristics of Coix lacryma-jobi L. such as tassel day, leaf number, plant height, effective tillers, effective panicle, grains per panicle, 1000-grain weight, and yield were recorded. The results show that different sowing dates could greatly affect the growth, development, and yield of Coix. This study also indicates that the yield of Coix is not determined by one single factor but by the product of three factors: 1000-grain weight, grain number, and effective panicles. As shown in the overall analysis, effective tillers of second and third periods were more than other periods. 1000-grain weight and grain number of these two periods on main stem and spike were also significantly higher than those of other periods. Therefore, to obtain the highest yield, the sowing date of Coix in Ya’an city should be late March to early April, which is in line with the analysis of tassel time, effective tillers, effective panicles, and grain number. Furthermore, our study provides valuable information on the optimal growth condition and high yield of Coix.