The 2012 ASHS Annual Conference

Chile (Capsicum annuum) is one of New Mexico’s leading horticultural commodities. Communities in northern New Mexico have deep rooted traditions of cultivating landrace chile varieties including ‘Chimayo’.  The chile landraces are highly adapted to growing conditions in northern New Mexico and have been touted for greater ability to withstand stressful growing conditions compared to commercial cultivars. Recently the pressure on farmers to conserve water has intensified due to drought conditions in the southwest. There is also evidence that chile heat level (SHU) and extractable color (ASTA) may be impacted by water stress in plants.  The objective of this experiment was to determine the effect of deficit irrigation on heat level and extractable color in two commercial chile cultivars (Big Jim and Sandia) and a landrace cultivar (Chimayo). The field was located in northern New Mexico at New Mexico State University’s Science Center in Alcalde, NM. Seeds were planted in the greenhouse on March 14, 2011, and transplanted to the field on May 17. The field experiment was a block design with three replications with four treatments, three subplots (3 m by 2.7 m) per replication, and thirty plants per subplot. Irrigation stress treatments started on June 20.  Four treatments were applied: 7 days (optimal watering), 9, 11, and 13 days (drought stress watering). Armin poly-pipe (20.3 cm) with 7.6 cm gates was used to furrow irrigate each row, with a Samani measurement flume in place to measure and ensure uniform water applications. Plants were harvested on August 12 and evaluated for extractable color, heat level, and other growth parameters. Results of this study did not support a correlation between deficit irrigation and extractable color. There was no significant difference in extractable color between the different irrigation treatments for either ‘Chimayo’ or ‘Sandia’. (‘Big Jim’, a slower-maturing cultivar, was not tested for extractable color because no ripe fruit were available at harvest.) Heat level was not significantly different between the irrigation treatments for ‘Chimayo’ and ‘Big Jim’. ‘Sandia was significantly hotter at the 9 day treatment (14,927 SHU) compared to the 7 day treatment (5,362 SHU), but neither of these levels was significantly different compared to the 11 day (9,312 SHU) and 13 day (10,605 SHU) irrigation treatments.