Genetics of destemming in pepper: A step towards mechanical harvesting

Authors: HILL, THERESA - University Of California; CASSIBBA, VINCENZO - University Of California; JOUKHADAR, ISRAEL - New Mexico State University; TONNESSEN, BRADLEY - Colorado State University; HAVLIK, CHARLES - New Mexico State University; ORTEGA, FRANCHESCA - New Mexico State University; SRIPOLCHAROEN, SIRISUPA - University Of California; VISSER, BERNARD - University Of California; STOFFEL, KEVIN - University Of California; THAMMAPICHAI, PARADEE - University Of California; GARCIA-LLANOS, ARMANDO - University Of California; CHEN, SHIYU - University Of California; Hulse-Kemp, Amanda; WALKER, STEPHANIE - New Mexico State University; VAN DEYNZE, ALLEN - University Of California

Submitted to: Frontiers in Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2023
Publication Date: 3/17/2023
Citation: Hill, T., Cassibba, V., Joukhadar, I., Tonnessen, B., Havlik, C., Ortega, F., Sripolcharoen, S., Visser, B.J., Stoffel, K., Thammapichai, P., Garcia-Llanos, A., Chen, S., Hulse-Kemp, A.M., Walker, S., Van Deynze, A. 2023. Genetics of destemming in pepper. Frontiers in Genetics. https://doi.org/doi:10.3389/fgene.2023.1114832.
DOI: https://doi.org/10.3389/fgene.2023.1114832

Interpretive Summary: The majority of peppers in the US for fresh marker and processing are handpicked representing a large production cost with field labor. Mechanical harvesting could potentially drop production costs by 20-50% if pepper varieties could be developed that are amenable to this production system. This work characterized green chile peppers to better understand the traits of being able to systematically, easily remove the stem which is necessary for mechanical harvest. This was done by looking at plant genetics, as well as the environment the plants were grown in, and the methods in which they could be mechanically harvested. We have been able to determine plant genetic components that are likely to make certain plants more amenable to mechanical harvesting, which will allow us to more quickly develop a pepper line that would utilize a mechanical harvest.

Technical Abstract: The majority of peppers in the US for fresh market and processing are handpicked, and harvesting can account for 20- 50% of production costs. Innovation in mechanical harvesting would increase availability; lower the costs of local, healthy vegetable products; and perhaps improve food safety and expand markets. In this paper, we present characterization and advancements in breeding green chile peppers for mechanical harvesting. We show that a systems approach is critical to success that includes genotype x environment x management (G x E x M), where M includes management, agronomic and harvester considerations. Specifically, we describe inheritance and expression of an easy-destemming trait in green chiles derived from a landrace, tools to measure the trait, its physiological basis, associated biochemical pathways, and expression of the trait in various genetic backgrounds and management systems.