Eduardo M. Kawakami and Derrick M. Oosterhuis AGRONOMIC, PHYSIOLOGICAL AND BIOCHEMICAL EFFECTS OF 1-MCP ON THE GROWTH AND YIELD OF COTTON Eduardo M. Kawakami and Derrick M. Oosterhuis

TOPICS Introduction Hypothesis and Objectives Cotton Crop Cotton Fruit Abscission 1-Methylcycloprone (1-MCP) Hypothesis and Objectives Field Study (Summer 2006) Field Study (Summer 2007) Growth Room Study (Spring 2007) Summary

Cotton Crop (Gossypium spp) Genus = Gossypium & Family = Malvaceae Important cash crop Unique about cotton Perennial Indeterminate Complex sympodial fruiting habit Very responsive to environment and management

Yield and Price of Cotton in Arkansas Since 1980 Min = 330 lb/acre Max = 1114 lb/acre Mean = 733.59 lb/acre Stdv = 179.66 lb/acre Year

New Challenges for Cotton Crop Decrease yield variability Increase yield potential No substantial increase in cost Understand and Decrease Cotton Fruit Abscission Main Effect “Stress” High Temperature Drought Ethylene Abscission

ETHYLENE PRODUCTION Days From Anthesis (μl/kg fresh wt/hr) Abscission Night Day ETHYLENE PRODUCTION (μl/kg fresh wt/hr) Abscission Abscission Abscission Night Day Days From Anthesis (Lipe and Morgan, 1973)

1-Methylcyclopropene New PGR from AgroFresh Approved for use in fruit and vegetable (EPA) Decreases or delays the effect of ethylene Occupies the ethylene receptors Affinity to receptor = 10 timer greater than ethylene Very stable and non-toxic Molecular weight of 54 g and formula of C4H6 CH3 (Blankenship and Dole, 2003)

Mode of action of ethylene C2H4 C2H4 C2H4 C2H4 Mode of action of ethylene

X Mechanism of 1-MCP blocking ethylene sites C2H4 C2H4 C2H4 C2H4 C4H6

Objectives 1-MCP Effect field and controlled environment Hypothesis inhibit the stress responses less fruit abscission and higher growth rates higher and less variable yields no changes in management and production costs 1-MCP Objectives 1-MCP Effect physiology fruiting dynamics yield field and controlled environment

Field Study Summer 2006 – Marianna, AR “TREATMENTS” Untreated control 1-MCP @ 10 g ai/ha at first flower (FF) 1-MCP @ 10 g ai/ha at FF, & at FF + 2 weeks 1-MCP @ 10 g ai/ha at FF, FF+1, FF+2, FF+3 weeks 1-MCP @ 10 g ai/ha + 20 oz PIX/ha at FF * Applied with a CO2 backpack spray calibrated to deliver 20 gal/acre ** The adjuvant AF-400 was used at 0.375% v/v Measurements Seedcotton yield Anti-oxidant Glutathione

Effect of 1-MCP on Seedcotton Yield (2006) a a a a a Seedcotton Yield (kg/ha)

Effect of 1-MCP on Anti-Oxidant Glutathione a b ab ab Glutathione (mM/g fresh wt.)

Field Study Summer 2007 Marianna, AR and Fayetteville, AR “TREATMENTS” Untreated control 1-MCP @ 10 g ai/ha at pin-head square (PHS) 1-MCP @ 10 g ai/ha at first flower (FF) 1-MCP @ 10 g ai/ha at FF, & at FF + 2 weeks * Applied with a CO2 backpack spray calibrated to deliver 20 gal/acre ** The adjuvant AF-400 was used with a dose of 0.375% v/v Measurements Seedcotton yield Chlorophyll Fluorescence Boll Size

Effect of 1-MCP on Seedcotton Yield (2007) a a a a Seedcotton Yield (kg/ha)

Effect of 1-MCP on Chlorophyll Fluorescence a b b b C. Fluorescence (Fv/Fm)

Effect of 1-MCP on Cotton Boll Size Treatment Boll from node 5* (g) Boll from node 11** T1. Untreated control 5.63 a*** 5.21 a T2. 1-MCP at PHS 5.94 ab 5.25 T3. 1-MCP at FF 6.56 b 5.79 bc T4. 1-MCP at FF, & at FF + 2 weeks 6.45 5.92 c *Boll tagged at the spraying day of treatment 3. ** Boll tagged at the spraying day of treatment 4. *** Rows with the same letters are not significant different (P=0.05) compared to the untreated control.

Growth Room Effect of 1-MCP on Cotton Flower Viability “TREATMENTS” Untreated white flowers collected 1 day after application. Untreated white flowers collected 2 days after application. Untreated white flowers collected 4 days after application. Untreated white flowers collected 8 days after application. Treated white flowers collected 1 day after application. Treated white flowers collected 2 days after application. Treated white flowers collected 4 days after application Treated white flowers collected 8 days after application. cv. DP 444 BG/RR Pot size: 1 liter Ambient: 30o/20oC (day/night) temperature, 12 photoperiods, 60% humidity Potting mixture: Sunshine horticultural mix

“MEASUREMENTS” Ethylene Boll Development

Effect of 1-MCP on Ethylene ul of Ethylene/ g.h Days after treatment

Effect of 1-MCP on Cotton Boll Development Boll Size (g) Days after treatment

Summary Cotton Crop Low Prices and Variability in Yield 1-Methylcyclopropene Short Term Solution Field and Growth Room Studies Positive Effect on Yield (Numerical) Increased Cotton Boll Size Showed Low Levels of Stress Changed Ethylene Synthesis Pattern Future Experiments ACC synthase and ACC oxidase Effect in the balance of the rest of the PGRs

Acknowledgments Agrofresh Inc. University of Arkansas