Determination of Optimum Plant Spacing for New Mexican Green Chile (Capsicum annuum)

New Mexican-type green chile is harvested when the fruit are fully sized, but physiologically immature, and quality is impacted by fruit size. Yield and fruit size are impacted by cultivar genetics, environmental conditions, and field management. One of these management factors is the spacing between plants. The standard spacing between plants in New Mexico is 30 cm, and in furrow-irrigated fields, 102 cm row spacing is typical. Early season stand losses due to disease or abiotic disorders may greatly increase the average spacing between plants. In addition, plant spacing closer than 30 cm has been shown to benefit mechanical harvest efficiency in red chile. However, the impact to fruit size must be considered as a preliminary step in utilizing this technique for green chile. This study investigated the effect of chile plant spacing on final green chile yield, fruit quality and plant habit attributes. A field at New Mexico State University’s Leyendecker Plant Science Research Center was direct seeded (2 kg/ac) with ‘New Mexico 6-4,’a standard New Mexico-type chile cultivar, on 11 Apr. 2014. The field was furrow irrigated and fertilized according to standard production practices in the area. On 6 June, six thinning treatments (152, 61, 30, 20, 15, and 7 cm spacing between plants) were applied to the field in a RCB design with six replications. Each treatment plot consisted of four concurrent rows, 3 m in length. On 8 Sep., data was collected from the two inner rows in each plot. Thinning treatment had no discernable affect on plant height and no impact on distance to primary node; however, plant width was significantly greater at the wider plant spacing and narrower at the closer plant space treatments. Significantly more basal branches were counted on plants in the wider spacing treatments. Fruit weight, length and wall thickness did not exhibit any treatment effects; however fruit were significantly wider in the wider plant spacing treatments. The overall yield was significantly less in the 152 cm treatment; however, there were no significant differences in yields in the other thinning treatments. Closer plant spacing did not adversely affect fruit yield and minimally affected quality; therefore, closer plant spacing should be further investigated for potential to improve mechanical harvest efficiency of green chile.