A Crop Phenology Model for Irrigated New Mexico Chile (Capsicum annuum L.) Type Varieties

Abstract

Field experiments were conducted with the objective of developing a general New Mexico chile type plant (Capsicum annuum L.) phenological model as a function of heat units accumulated after planting (HUAP). Field experiments were conducted from 2003 through 2005 in the Sulfur Springs Valley of Arizona, near Sunsites in Cochise County, Arizona (31° 56" N, 109° 52" W, about 4,000 feet elevation) on a Borderline fine sandy loam (coarse-loamy, mixed, superactive thermic Typic Calcigypsids) and in the Animas Valley, New Mexico (31° 57" N, 109° 48" W, about 4,400 feet elevation), on a Vekol fine sandy clay loam (fine, mixed, thermic, Typic Haplargids). Plant measurements were collected routinely and important phenological stages that corresponded to first bloom, early bloom, peak bloom, physiological maturity, and red harvest were identified and recorded. Results indicate that within locations, all varieties performed similarly in relation to HU accumulation patterns. A general New Mexico chile type plant phenological model as a function of HUAP for all sites and varieties was obtained. First bloom occurred at 954 ± 254 HUAP, early bloom at 1349 ± 306 HUAP, peak bloom at 1810 ± 261 HUAP, physiological maturity at 2393 ± 215 HUAP, and red chile harvest was identified to occur at 3159 ± 220 HUAP. The purpose of this phenological baseline or model is to provide a crop management tool for growers for predicting and identifying critical stages of growth. Further development and validation of this model is a continued objective of this research program.