Harvest of Southern Highbush Blueberry with a Modified, Over-the-Row Mechanical Harvester: Use of Soft-Catch Surfaces to Minimize Impact Bruising

Abstract

Harvest of fresh market, southern highbush blueberries (SHB) is labor intensive and costly, leading to a demand for alternative harvest methods. Recent research has shown potential for mechanically harvesting blueberries with minimal bruising by using a modified over-the-row (OTR) harvester. For two harvests, SHB cultivars Optimus and Vireo were either hand-harvested (HH) or mechanically harvested (MH) by two commercial harvesters, one unmodified with standard hard-catch surfaces (HCS) or by the other modified with soft-catch surfaces (SCS). For Harvest 1, fruit from all harvest methods were hand-sorted into the following categories: blue fruit (marketable), red fruit, green fruit and culls. Samples from each cultivar and treatment were then held at 24 °C overnight, and the following day firmness and impact bruise severity were determined. Harvest 2 had identical harvest treatments; however, the fruit were sorted on a commercial packing line prior to packing in clamshells (n = 16). A subsample was held overnight as in Harvest 1 for bruise severity rating, while the remaining fruit were stored at 1 °C for 14 days (d). Although percent marketable fruit was more affected by cultivar than harvest method, determination of bruise severity revealed the benefit of harvest with SCS over HCS for both cultivars. The former had 16–26% severe bruising, compared to 27–40% for the latter; HH had 1–4%. During storage, HH fruit remained firmer than HCS and SCS, which were similar. After 14 d, firmness for “Optimus” was 239 N (HH), 157 N (HCS and SCS) and for “Vireo” it was 189 (HH), 155 N (HCS and SCS). Fruit weight loss increased during storage (1.1–4.4%), but there was no difference due to catch plate surface. SSC, TTA and Ratio were not affected by catch surface type or storage period within cultivar. Using modifications such as “soft” catch surfaces on currently available OTR harvesters reduces impact bruise damage; however, impacts incurred during commercial packing operations can negate this effect. MH for fresh market blueberries may provide an economical alternative for blueberry growers; however, with current technology, the fruit should be utilized within a week of harvest.

Improving Blueberry Fruit Nutritional Quality through Physiological and Genetic Interventions: A Review of Current Research and Future Directions

“…The commercialisation of blueberries has relied on developing hybrids between the tetraploid lowbush V. angustifolium (2n = 4x = 48), tetraploid highbush V. corymbosum L. (2n = 4x = 48), and the hexaploid rabbiteye V. virgatum (2n = 6x = 72) [ 20 ]. Although most blueberry breeding efforts have focussed on soil and climate adaptation, early bloom, and fruit traits such as size, firmness, and sweetness, due to the high labour cost of harvesting, the blueberry industry’s current trait priorities are bush architecture, loose fruit clusters and easy detachment of mature fruit that will allow for machine harvesting [ 21 , 22 ].…”

HPPEM: A High-Precision Blueberry Cluster Phenotype Extraction Model Based on Hybrid Task Cascade

“…The global blueberry production rose from 622,900 tons in 2016 to 850,900 tons by 2020 [3,4]. The traditional harvesting of highbush blueberries is completed by hand in batches, which generally lasts for three to four weeks, thus requiring a large amount of labor during the harvest season [5]. With the surge in global blueberry production, labor costs are rising rapidly.…”

“…The "granular" mode of mechanical harvesting is suitable for blueberry varieties with loose clusters. Breeding blueberry varieties for mechanical harvesting has been underway since the mid-1990s [5]. According to blueberry breeders, in order to develop varieties suitable for mechanical harvesting, the following factors should be taken into account: narrow upright bush structure, relatively concentrated ripening of fruits, and loose clusters.…”

Design and Analysis of a Flexible Adaptive Supporting Device for Banana Harvest

“…Researchers from all over the world have carried out many studies on the robotic harvesting of various fruits and vegetables [5,6], for example the tomato picking robot [7], strawberry picking robot [8,9], watermelon harvesting robot [10], and the lettuce harvesting robot [11]. Compared with picking machines, these picking robots are more automated and intelligent.…”