Sowing Dates and Melatonin Application Impact on Soybean Growth and Yield in Western Region of Iraq

Abstract

Global warming led to many environmental changes, temperature and photo period are noticeably altered within regions, hence, sowing crops in same recommended dates might affect their growth and production due to those environmental changes. The idea here in this study was to investigate the influence of changing sowing date on soybean growth and production. Plants subjected to extreme early and late dates (five dates started from 10th of Aprile with 15-day interval) and melatonin foliar application (0 µM, 100 µM, 200 µM and 300 µM). Obtained results showed great response of soybean, some traits appeared superior in particular dates while others showed the opposite. Plants sown very late in 9th Jun and those sown as recommended in 10th May both gave the highest value of plant height with no significant difference, while the lowest plant hight was reported for plants sown early 10th of Aprile. Plant leaf area appeared high for the plants sown in 9th of Jun. On the other hand, early sown plants had lowest value of plant leaf area. Recommended date gave highest number of branches, while very late date had the minimum. Pods number per plant presented high value at recommended date with no significant differences with plants sown late in May and Jun. plants sown in 10th Aprile and 25th Aprile gave highest total seed yield. Melatonin played interesting role improving all studied traits and mainly increased the yield and minimized the reduction in yield for plants sown early and late.