Hill Theresa, Cassibba Vincenzo, Joukhadar Israel, Tonnessen Bradley, Havlik Charles, Ortega Franchesca, Sripolcharoen Sirisupa, Visser Bernard Jurriaan, Stoffel Kevin, Thammapichai Paradee, Garcia-Llanos Armando, Chen Shiyu, Hulse-Kemp Amanda, Walker Stephanie, Van Deynze Allen
Seed Biotechnology Center, University of California, Davis, Davis, CA, United States.
Department of Extension Plant Sciences, New Mexico State University, Las Cruces, NM, United States.
Front Genet. 2023 Mar 17;14:1114832. doi: 10.3389/fgene.2023.1114832. eCollection 2023.
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. Most processed peppers require removal of pedicels (stem and calyx) from the fruit, but lack of an efficient mechanical process for this operation has hindered adoption of mechanical harvest. In this paper, we present characterization and advancements in breeding green chile peppers for mechanical harvesting. Specifically, we describe inheritance and expression of an easy-destemming trait derived from the landrace UCD-14 that facilitates machine harvest of green chiles. A torque gauge was used for measuring bending forces similar to those of a harvester and applied to two biparental populations segregating for destemming force and rate. Genotyping by sequencing was used to generate genetic maps for quantitative trait locus (QTL) analyses. A major destemming QTL was found on chromosome 10 across populations and environments. Eight additional population and/or environment-specific QTL were also identified. Chromosome 10 QTL markers were used to help introgress the destemming trait into jalapeño-type peppers. Low destemming force lines combined with improvements in transplant production enabled mechanical harvest of destemmed fruit at a rate of 41% versus 2% with a commercial jalapeńo hybrid. Staining for the presence of lignin at the pedicel/fruit boundary indicated the presence of an abscission zone and homologs of genes known to affect organ abscission were found under several QTL, suggesting that the easy-destemming trait may be due to the presence and activation of a pedicel/fruit abscission zone. Presented here are tools to measure the easy-destemming trait, its physiological basis, possible molecular pathways, and expression of the trait in various genetic backgrounds. Mechanical harvest of destemmed mature green chile fruits was achieved by combining easy-destemming with transplant management.
美国用于鲜销和加工的辣椒大多是人工采摘的，采收成本占生产成本的20%-50%。机械采收技术的创新将增加辣椒的供应量；降低本地健康蔬菜产品的成本；或许还能提高食品安全水平并拓展市场。大多数加工辣椒需要从果实上去除果柄（茎和花萼），但缺乏针对此操作的高效机械工艺阻碍了机械采收技术的应用。在本文中，我们展示了为实现机械采收而对青辣椒进行选育的特性及进展。具体而言，我们描述了源自地方品种UCD-14的易去柄特性的遗传和表达情况，该特性有助于青辣椒的机械采收。使用扭矩计测量类似于收割机施加的弯曲力，并将其应用于两个因去柄力和去柄率而分离的双亲群体。通过测序进行基因分型以生成遗传图谱用于数量性状位点（QTL）分析。在多个群体和环境中，在第10号染色体上发现了一个主要的去柄QTL。还鉴定出另外8个特定于群体和/或环境的QTL。利用第10号染色体上的QTL标记，帮助将去柄性状导入墨西哥胡椒类型的辣椒中。低去柄力品系与移栽生产的改进相结合，使得去柄果实的机械采收率达到41%，而商业化墨西哥胡椒杂交品种的采收率为2%。对果柄/果实边界处木质素存在情况的染色表明存在离层区，并且在几个QTL下发现了已知影响器官脱落的基因的同源物，这表明易去柄性状可能归因于果柄/果实离层区的存在和激活。本文介绍了测量易去柄性状的工具、其生理基础、可能的分子途径以及该性状在各种遗传背景下的表达情况。通过将易去柄特性与移栽管理相结合，实现了去柄成熟青辣椒果实的机械采收。
