2018 ASHS Annual Conference

Closer plant spacing influences the plant growth habit of New Mexico chile by creating taller plants with fewer basal branches and higher fruit set. These traits are beneficial to mechanical harvest efficiency. Experiments conducted in 2015 and 2016 at New Mexico State University’s Los Lunas Agricultural Science Center investigated the impact of thinning NM green chile plants to 4 and 8 inch spacing on mechanical harvest efficiency, and if closer plant spacing would adversely affect green chile fruit size. Two commercial New Mexico green chile cultivars, ‘NuMex Joe E. Parker’ (Biad Chili Company, Las Cruces, NM) and ‘AZ-1904’ (Curry Chile and Seed Company, Pearce, AZ), were direct seeded on 17 Apr. 2015 and 14 Apr. 2016. Three thinning treatments (4, 8 and 12 inch plant spacing) were established in a randomized complete block design with five replications. Plots were thinned on 11 Jun. 2015 and 14 Jun. 2016. The field was flood irrigated, fertilized and cultivated as needed. Plant measurements including height and width, height to main bifurcation, stem diameter, and number of basal branches were recorded immediately before harvest. An Etgar Series MOSES 1010 (Bet-Lehem-Haglilit, Israel) was used to mechanically harvest the plots on 2 Sept. 2015 and 31 Aug. 2016. Harvested material was sorted and weighed by marketable green fruit, broken fruit, and non-fruit plant material. Weight of fruit dropped on the ground and fruit left on the plants following harvest was also measured. Fruit dimensions (weight, width, length, and wall thickness) from a subsample of the harvested pods were recorded. Results were similar in both years. Overall, ‘NuMex Joe E. Parker’ provided higher mechanically harvested green chile fruit yield than ‘AZ-1904’. ‘NuMex Joe E. Parker’ with the 4 inch thinning had the most marketable green yield of 28,160 lb/acre, 101.4% more than the lowest yielding ‘AZ-1904’ with the 12 inch thinning. ‘AZ-1904’ fruit from the 4 inch thinning was significantly longer (22.6 cm) and heavier (112.6 gm) when compared to all ‘NuMex Joe E. Parker’ and ‘AZ-1904’ 8 and 12 inch thinning treatments. Fruit width and number of locules were not affected by thinning treatments. ‘NuMex Joe E. Parker’ at the 4 inch thinning had the tallest plants (73.9 cm) and also had the highest height to bifurcation at the 4 and 8 inch thinning treatments, 23.3 cm and 23.6 cm respectively. Both cultivars had a higher bifurcation value as the spacing between plants decreased.