Managing Crop Load in European Pear (Pyrus communis L.)—A Review

Abstract

Reducing levels of fruit set is often desirable in many European pear (Pyrus communis L.) cultivars. With a negative linear relationship between crop load and fruit size, crop load management early in the season minimises wastage of tree carbohydrate resources and provides maximum benefits in terms of fruit size and quality. There are several tools available for managing crop load including hand thinning, chemical thinning, photosynthetic inhibition through shading or application of chemicals, mechanical thinning and pruning. While hand thinning is the most accurate method of reducing excessive crop loads, there are some major drawbacks. With awareness that the early thinning offered by chemical thinning provides distinct advantages with regard to fruit size and other quality parameters, chemical thinning is gaining increasing acceptance in pear production. Some chemicals are used worldwide for thinning, but there are differences between countries and growing regions on recommended application timing and concentrations. The risks involved in chemical thinning can be mitigated by use of a structured approach, using a sequential spray program with both bloom and post-bloom thinners. Knowledge of conditions that impact the carbon balance of the tree and the ability to make use of carbon-deficit conditions are likely to improve the predictability of chemical thinning. Mechanical thinning has potential as a thinning tool, with advantages over chemical thinning in that it is environmentally friendly, can be used in organic production and is not weather dependent. Although artificial bud extinction has not been trialled on pears to date, it has been shown to be economically viable in apple. As it is a precision crop load management method that minimises tree resource wastage, it should be given serious consideration. As growers require large annual yields of high-quality fruit, the aim of this review was to examine current and potential crop load management methods for European pear cultivars and provide a portfolio of available options that can be integrated into a systematic approach for managing crop load.

Influencing Factors of Cutting Force for Apple Tree Branch Pruning

“…All apple trees require pruning in winter, which is a critical management to promote apple yield by adjusting nutrition distribution [1]. Pruning can reduce competition for assimilates thus providing maximum benefit in terms of assimilating distribution; and it is an environmentally friendly method of reducing crop load [2]. Pruning can be carried out manually or mechanically using pruning tool [3].…”

Pear (Pyrus communisL. cv. Conference) has shade-tolerant features allowing for consistent agrivoltaic crop yield

“…These observations contradict earlier findings for apple under AV (Juillion et al, 2022), which recorded a reduced flower bud development and a decreased fruit drop under AV, for a Mediterranean climate. Whereas bud development determines fruit number at harvest, fruit size potential is largely influenced by cell division after pollination (Bound, 2021). According to Graham et al (2021), pollinator behavior is unaffected by partial shade of PV systems.…”

“…Whereas bud development determines fruit number at harvest, fruit size potential is largely influenced by cell division after pollination (Bound, 2021). According to Graham et al (2021), pollinator behavior is unaffected by partial shade of PV systems.…”

“…However, we did not observe this effect under AV, recording similar fruit drop levels as for the hail-netting control. Hand thinning of excess fruitlets can be an effective tool in selecting for fruit size (Bound, 2021). Bearing in mind the relation we observed between bottle-shaped fruit and apical flower position(Claessen et al ., 2021) clever hand thinning may increase harvest quality significantly.…”

Manufacture of a Device for Pruning Fruit Branches

“…Furthermore, pruning can lessen competition for assimilates, thereby maximizing assimilate distribution, and it is an eco-friendly aspect of diminishing crop load (Bound, 2021). Pruning is the second greatest labor expense after harvesting expenses in tree fruit production, representing approximately 20% or over of the entire pre-harvest production cost (Gallardo et al 2009;Hansen 2011).…”