Low temperature stress at different flower developmental stages affects pollen development, pollination, and pod set in soybean

Pod set, a critical process for legume crop productivity, is sensitive to environmental stress such as low or high temperature or drought At higher latitudes, pod set at low temperatures is one of the most important processes for efficient soybean production The present study was car nett out to determine which flower developmental stage was most sensitive to low temper attire and how low temperature interrupts the pod setting process Soybean flowers at various developmental stages were subjected to low temper attires, and the percentage elongation of pods was subsequently measured Two low temperature-sensitive stages were found The first was an early developmental stage approximately 12 5 days before the anthesis of individual flowers The second stage occurred 3-4 days before anthesis An investigation of the pollen grain number on stigma suggests that insufficient pollination causes low pod set under low temperature stress at both temperature-sensitive stages Tetrad-shaped abnormal pollen grains were observed when flowers were subjected to low temperature at the fist sensitive stage; thus, this stage might be the tetrad stage or the stage prior to tetrad formation Furthermore, at the first sensitive stage, pollen development deficiency was one of the causes of poor pod set under low temper attire conditions (C) 2010 Elsevier B V All rights reserved.