Manual harvesting of fruits is an expensive, time-consuming, and labor-intensive operation. Due to labor shortages in the late 1950s, mechanical harvesters were developed to reduce the need for labor and to reduce cost. The most common mechanical harvesters are limb, trunk, and canopy shakers. Catch frames are used during mechanical harvesting to collect fruits and reduce fruit damage. Efficient fruit harvesting without tree damage requires selecting the appropriate harvesting technology based on: (1) tree characteristics – type, size, natural frequency, damping properties, and the architecture of the tree; (2) fruit properties – shape, size, stem length, and maturity level; and (3) vibration techniques – shaker type, mass, amplitude, excitation frequency, and clamp position. Although mechanical harvesting increases harvest efficiency, it has disadvantages, which can include (a) tree injury, (b) fruit damage, (c) debris and trash, (d) the need for specific orchard design and tree training, (e) significant capital investment, and (f) machine maintenance costs. Recent advancements in sensing and machine vision techniques have significantly improved automation in new mechanical harvesters, and increased the efficiency and productivity of new harvesting machines. Growers can benefit from smart harvesters that are less operator-dependent. In addition, because harvesters are expensive and not used for more than two months a year, much tree crop harvesting is contracted with commercial services, making harvest time an important parameter. This review discusses the current mechanical harvesting technologies for some selected temperate and tropical nut and fruit trees, the factors affecting mechanical harvesting, smart harvesting techniques and challenges, and provides an overview of mechanical harvesting and its future outlook.
Banana is one of the leading crops in world fruit production and world trade. It is grown globally in subtropical and tropical regions, and can be served for fresh consumption or used as a staple food in many countries. Postharvest physiological disorders are a major threat to the banana fruit industry and can cause significant economic losses worldwide. Such disorders include finger drop, senescent spotting, and chilling injury. These are common disorders of banana which are associated with more than one factor, such as environmental conditions in conjunction with genetic factors, but some disorders mainly occur due to only one factor. There is a need, therefore, to understand the basic causes behind a particular disorder and how it can be overcome with appropriate management practices. This review not only describes the causes of such postharvest physiological disorders of banana, but also discusses the biochemical processes involved in their development. Practical management methods that can be used to prevent the disorders and to retain fruit quality for high value markets are presented.
Oakleaf hydrangea is a shrub that is native to the southeastern United States and is growing in popularity as an ornamental plant. Like other cultivated hydrangea species, oakleaf hydrangea has showy flowers but also has unique phenotypic characteristics that provide additional value as an ornamental shrub. Despite the enormous popularity of hydrangeas as garden plants, little research has been done on oakleaf hydrangea. This review synthesizes the existing oakleaf hydrangea literature and draws on work done in other Hydrangea species to bring attention to the current knowledge and identify gaps to be filled. After introducing the genus, the review focuses on the horticultural aspects of oakleaf hydrangea, genetics and breeding of several selected traits, as well as the conservation concerns for the species. Finally, future lines of research that would provide valuable information for the breeding and conservation of oakleaf hydrangea are suggested.
Apple crop load management and related fruitlet abscission have been major research priorities for the last century in pomology. From these efforts, two main models were developed to explain the mechanisms leading to fruitlet abscission: correlatively driven abscission proposed by Bangerth; and carbohydrate stress initially proposed by Botton et al. Both models agree on the final step leading to differentiation of the abscission zone, specifically decreased polar auxin transport through the abscission zone, causing it to become sensitive to ethylene. However, these models propose different abscission induction mechanisms. Correlatively driven abscission proposes that polar auxin transport of fruitlets within a spur meet at "autoinhibitory junctions" in the peduncle, where polar auxin transport from dominant fruitlets can reduce that from inhibited fruitlets. The carbohydrate stress model proposes that polar auxin transport ceases because of embryo death in the seed following an increase in ethylene biosynthesis in the cortex due to chemically- or naturally-induced oxidative stress from limited carbohydrate availability. We provide an overview of the studies that led to these models and analyze their validity in the context of physiological factors that have been shown to affect apple fruit abscission, including chemical thinner mode of action, and king dominance.
Chapter 2 Biostimulants in Agricultural and Horticultural Production Jessica C. Bell, Jessica C. Bell Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, AustraliaSearch for more papers by this authorSally A. Bound, Sally A. Bound Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, AustraliaSearch for more papers by this authorMichele Buntain, Michele Buntain Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, AustraliaSearch for more papers by this author Jessica C. Bell, Jessica C. Bell Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, AustraliaSearch for more papers by this authorSally A. Bound, Sally A. Bound Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, AustraliaSearch for more papers by this authorMichele Buntain, Michele Buntain Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, AustraliaSearch for more papers by this author Book Editor(s):Ian Warrington, Ian Warrington Massey University, New ZealandSearch for more papers by this author First published: 04 November 2021 https://doi.org/10.1002/9781119851981.ch2 AboutPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShareShare a linkShare onFacebookTwitterLinked InRedditWechat Summary Plant biostimulants offer promising opportunities to aid in addressing the challenges faced by contemporary agriculture – maintaining viable yields of high-quality produce while reducing the environmental footprint of production. Biostimulants have been shown to enhance plant growth, boost yields, and increase crop tolerance to abiotic stress, acting via a number of mechanisms including phytostimulation, biofertilization, and biocontrol. In the European Union, frameworks and industry standards that require rigorous scientific evidence for all claims have been introduced as a requirement for product registration. However, a lack of regulation in many countries, including Australia, has led to significant variation in product quality and inconsistent results in the field, issues that remain to be addressed. As industry develops the next generation of biostimulant products, the potential for synergistic effects when applying different categories of biostimulants in combination has generated particular interest. In the realm of microbial inoculants, the formulation of microbial consortia which look to harness the beneficial action of multiple species is being investigated. The potential for biostimulants to add value to soilless production systems is another area for development in this space. As biostimulants encompass a diverse group of products, this review focuses on three categories: microbial inoculants, humic substances, and seaweed extracts. After summarising the current understanding of how these substances operate, as well as the crop responses they have been shown to elicit, we examine the challenges facing the development of more effective and reliable products and explore some of the key areas for future research. Horticultural Reviews, Volume 49 RelatedInformation
