Effect of 1-MCP on Cotton Plants under Abiotic Stress Caused by Ethephon

Abstract

Many environmental stress factors have been identified to increase square and boll abscission and thus result in reduced cotton yield. Under stress conditions, ethylene is elicited. Ethylene peaks before abscission to promote the formation of the abscission layer and plays a major role in early season square and boll abortion in cotton ( Gossypium hirsutum L.). In addition, ethylene stimulates the leaf senescence process. Thus, it is desirable to protect plants from ethylene-induced fruit loss and premature leaf senescence under stress conditions. The objective of this study was to evaluate the ability of 1-methylcyclopropene (1-MCP) to protect cotton plants against abiotic stress caused by ethephon (ethylene promoting effect). Field studies using a randomized complete block design with four replications were conducted in 2010 and 2011 at Texas A&M AgriLIFE Research Farm in Burleson County, TX. Eight treatments that consisted of two 1-MCP rates (0 and 10 g a.i. ha -1 ) in combination with four ethephon rates (0, 146, 292, 438 mL &middot ha -1 ) were imposed at the first flower (FF) stage of the development. 1-MCP increased plant height and number of main stem nodes in both years. In addition, 1-MCP-treated plants exhibited greater membrane integrity and increased photosystem II quantum efficiency and thus delayed senescence in both years. These potentials for yield increase were realized in 2011 with 1-MCP treatment exhibiting a higher lint yield. In 2012, although 1-MCP treatment increased number of open fruit and open fruit weight per plant significantly, no significant lint yield increase was detected.