Comparative Mechanical Harvest Efficiency of Six New Mexico-Pod Type Green Chile Cultivars
General Material Designation
[Thesis]
First Statement of Responsibility
Joukhadar, Israel Sevanne
Subsequent Statement of Responsibility
Walker, Stephanie J.
.PUBLICATION, DISTRIBUTION, ETC
Name of Publisher, Distributor, etc.
New Mexico State University
Date of Publication, Distribution, etc.
2019
PHYSICAL DESCRIPTION
Specific Material Designation and Extent of Item
161
DISSERTATION (THESIS) NOTE
Dissertation or thesis details and type of degree
Ph.D.
Body granting the degree
New Mexico State University
Text preceding or following the note
2019
SUMMARY OR ABSTRACT
Text of Note
New Mexico-pod type green chile (Capsicum annuum) is one of New Mexico's leading horticultural commodities. Cultivated acreage of green chile in New Mexico is threatened due to the high cost and unavailability of labor for hand harvest. Therefore, mechanization is necessary to sustain the industry. Successful mechanization depends on harvester design coupled with plant architecture that optimizes harvest yield and quality. Harvested green fruit must be whole, unbroken, and unblemished for fresh and processed markets so harvester design and plant architecture must maximize yield while minimizing fruit damage. In two trials conducted at New Mexico State University Agricultural Science Center in Los Lunas, New Mexico, six cultivars (AZ-1904, Machete, PHB-205, E9, PDJ.7, and RK3-35) were evaluated for plant architecture and harvest efficiency with a double, open-helix mechanical harvester. Cultivars were direct seeded on 17 April 2015 and 14 April 2016 and managed according to standard production practices. Plant architecture traits, plant width (cm), plant height (cm), height to first primary branch (cm), distance between first primary branch and first node (cm), basal stem diameter (mm), and number of basal branches were measured before harvest. Mechanical harvest yield components, marketable fruit, broken fruit, ground fall losses, unharvested remaining on branches, and non-pod plant material were assessed after a once-over destructive harvest on 2 Sept. 2015 and 31 Aug. 2016. Fruit characteristics, fruit width (cm), fruit length (cm), and pericarp thickness (mm) were measured from a representative sample of ten marketable fruit. In 2015, 'AZ-1904' and 'PDJ.7' had significantly (P ≤ 0.05) more marketable yield than 'Machete', which had the least marketable yield. No statistically significant differences were found in marketable yield in 2016. When both years were combined, 'PDJ.7' had significantly more non-pod plant material harvested and taller plants than all other cultivars. We found mechanical harvest performance to be significantly affected by plant height, shorter plants yield less marketable fruit. Despite differences in fruit wall thickness, no significant differences were measured in broken fruit. 'E9', 'RK3-35', 'Machete', 'PHB-205', and 'PDJ.7' all had significantly more basal branches per plant, compared to 'AZ-1904' with significantly fewer basal branches in 2015. Harvest efficiencies (marketable harvested fruit yield as a percentage of total plot yields) ranged from 64.6-39.3% during this two-year trial, with the highest harvesting cultivars, 'PDJ.7' and 'AZ-1904'. In the future all New Mexico pod-type green chile breeding efforts for mechanical harvest must incorporate desirable plant architecture traits to increase harvest efficiencies.