1-Methylcyclopropene Effects on Field-Grown Cotton: Physiological Characteristics

Cotton (Gossypium hirsutum L.) is the lead cash crop in Texas, and its productivity is often challenged by stressful environmental conditions such as high temperatures and sub-optimal water supply. The objective of this investigation was to assess the impact of 1-methylcyclopropene (1-MCP) applications triggered by canopy temperature and forecasted ambient temperatures on field-grown cotton plants. Physiological responses to 1-MCP applications were investigated in field studies conducted during the summers of 2012-2014 at the Texas A&M University Field Laboratory in Burleson County, TX. During all three growing seasons, more than 65% of the days reached temperatures above 28 degrees C, which indicated great potential for high temperature stress. Daily plant canopy temperature, net photosynthesis, transpiration, and photosystem II quantum yield were affected by 1-MCP treatment when plants were irrigated, but not under dryland conditions. Positive effects of 1-MCP were found for fruit retention in 2013 and 2014, for both irrigated and dryland studies, although a negative impact was found in the 2012 irrigated study. Applications of 1-MCP affected physiological characteristics; however, it did not affect crop yield.