1- Methylcyclopropene Influence on Cotton Fruit Set.

1-methylcyclopropene (1-MCP) is an ethylene action inhibitor applied widely in horticultural crops to counter ethylene effects on fruit abscission. Fruit loss in cotton (Gossypium hirsutum L.) plants is caused by greater ethylene synthesis in response to stress. The objective of this study was to evaluate the effects of 1-MCP treatment on cotton fruit set of plants experiencing an imposed stress. A field study was conducted in 2007 at the Texas Agricultural Experiment Station in Burleson County, Texas, as a randomized complete block design with four replications. Treatments were three rates of 1-MCP (0, 0.36, and 0.72 oz a.i. acre^-1) in combination with a surfactant at rates of 0 and 0.375% v v^-1 applied 93 days after planting. On the following day, ethephon (ethylene synthetic hormone) was applied at 0 and 4 oz acre^-1, as a source of stress. Both rates of 1-MCP together with surfactant had 20 to 50 % more squares than the zero control. Independently of surfactant, all 1-MCP treatments abscised less fruit than the ethephon control. However, the ethephon control possessed the greatest number of green bolls.  
Results suggest that 1-MCP treated plants may have potential to compensate for the effects of the late season stress by producing and/or retaining a greater fruit set on the plant.