PRODUCTION

APPLES & PEARS PRODUCTION

The  Crop Production Programme is managed by Prof. Wiehann Steyn and the research strategy is directed and aligned with the requirements and key risks to the ‘Orchard of the Future’.  Hence, farming efficiency (of which rootstocks, plant quality and orchard efficiency are key components) as well as water- and climate-related research are the strategic priorities of this programme.

Rootstocks that are more yield efficient and adapted to South African conditions is a key priority and necessity for achieving the objectives of the orchard of the future. It therefore comes as no surprise that most of our crop production projects are aimed at evaluating rootstocks. While we are awaiting the results of these trials, Dr Elmi Lötze’s project on rootstock adaptability to high temperatures questioned the belief that M9 apple rootstock is not adapted to South African conditions. Based on her findings, South African producers should reconsider their hesitancy to utilise dwarfing rootstocks.

Allowing growers to harness the benefits of dwarfing rootstocks may be one of the potential benefits of installing hail/shade nets according Willie Kotze’s research. In addition to the proven benefit of reducing sunburn in Granny Smith, other potential benefits of netting (e.g. water saving and increased spray efficiency) that still need to be quantified under South African conditions should form part of the equation when deciding on whether to net or not.

Progress report: Orchard of the Future

Nearly seven years ago HORTGRO Science challenged the apple industry through its Orchard of the Future (OoF) project. The project encouraged orchard designs that were novel, ‘outside of the box’, and pushed the limits of conventional fruit production systems. This is a review of the project where project leaders provided progress on their OoF blocks. Read the full article here 

ZZ2’s Hendrik Pohl joins ‘Orchard of the Future’ pack

In 2016 apple grower, Hendrik Pohl from ZZ2, joined the Orchard of the Future project with his Bokveldskloof orchard block. The goals for Pohl’s orchard are ambitious and seek to demonstrate the interplay between rootstock and planting density in terms of cost and meeting production goals. HORTGRO Science spoke to Hendrik about his background and his views on fruit production. Read the full article here 

The ‘Net Gain’ amid water & climate challenges

This blog article is about water and climate and how the management of orchards under nets can factor into this equation. Research in the Crop Production programme is aimed at achieving the goals and address risks to the Orchard of the Future. Read the full article here 

Ripening Associated Red Color Development Masks Sunburn Browning in Apple Peel

Red color development toward harvest may conceal superficial blemishes such as sunburn browning in apple peel. Masking of sunburn may result in the underestimation of sunburn incidence in full red and blushed cultivars and may result in inaccurate assessments of sunburn susceptibility of various cultivars. Find a link to the full article here: http://hortsci.ashspublications.org/content/50/6/814.abstract  

 

The Art of Mutualism – investing in our Researchers

In Biology mutualism refers to the way two organisms of different species exist in a relationship in which each individual benefits. In the deciduous fruit industry a similar relationship exists between academia and the growers on the ground. Read about this special relationship and why we need to invest in human capital if we want to secure the future of the deciduous industry.
DOCUMENTS: THE ART OF MUTUALISM

Gums and Bees – a roadmap for landowners in South Africa.

This booklet aims to help landowners protect or grow forage resources for honey bees, and understand why Eucalyptus trees are vital to the beekeeping and agricultural industries in South Africa. You can also watch a related YouTube video here: https://www.youtube.com/watch?v=yMQkJkbtIKM
DOCUMENTS: GumsBees WEB version with hyperlinks

CALCIUM AND BORON MIX MAKES A GOOD SUNBLOCK for ‘GOLDEN DELICIOUS’ APPLES
Sunburn damage to “Golden Delicious” apples can be curbed by spraying trees with a mixture of calcium and boron. This advice from Dr Elmi Lötze and Dr Lynn Hoffman of the Department of Horticultural Science at Stellenbosch University is published in a new article in the Journal of Horticultural Science & Biotechnology. They found that such sun damage can be halved by spraying apple trees after full bloom with this mineral rich nutrition combination.
DOCUMENTS: SunburnGoldenDeliciousFINAL 
The Buzz for Food. THE ROLE OF THE HONEY BEE
This document and short film about the role of the honey bee in the growing of fruit, illustrates the importance that growers work with Mother Nature in order to benefit from her. Material provided by Sanbi.  For a link to the video, follow: https://www.youtube.com/watch?v=yMQkJkbtIKM
DOCUMENTS: HONBEYBEES IN SA BROCHURE PRINT
MANAGING APPLE REPLANT DISEASE: THE EFFECT OF BIOLOGICAL SOIL AMENDMENTS ON TREE PERFORMANCE
Apple replant disease (ARD) is a disorder associated with the poor growth of young apple trees planted on sites where apples were planted previously. It is a major impediment in establishing an economically viable apple industry and an increasingly important problem due to limited availability of suitable virgin soil sites.
DOCUMENTS:
lvschoor_bio-amendment_ (1.4 MB)
lvschoor_apple_replant (38.5 KB)
PRE AND POST HARVEST MANAGEMENT OF BITTER PIT APPLES
There is an ongoing need to utilise management practices that create a balance in orchards such that the effects of the many interacting internal and external factors that contribute to bitter pit are minimised. (Wooldridge, 2001) This article summarises the main pre- and post-harvest management factors that can be manipulated in order to reduce the risk of bitter pit, and further actions are suggested. Additional information can be accessed in the articles listed in the references.
DOCUMENTS: Pre- and post-harvest management of bitter pit on apples.PDF (68.5 KB)
REST BREAKING GUIDELINES
The objectives of application of rest-breaking products are to: Maximise budburst of reproductive spurs in order to maximise yield in the same season. Maximise budburst of lateral buds on year-old shoots (vegetative shoots) so as to increase the number of potential fruiting sites to increase future yields. Optimise uniformity of blossom. This is important for successful chemical thinning and timing of other sprays.
DOCUMENTS: Rest Breaking Guidelines .PDF (95.3 KB)
THE MYCORRHIZAL FUNGUS A CONTRIBUTOR TO SOIL AND ROOT HEALTH
Arbuscular mycorrhizal (AM) fungi are an exceptional group of beneficial fungi.  They are present in most soils and are capable of forming associations with the root systems of the great majority of vascular plant species where they act as bioregulators and protectors, and facilitate the uptake of mineral nutrients (Lovato et al., 1996).  This article concerns the relationship that AM fungi have with deciduous fruit trees and grapevines, a topic that has received little attention in the popular press to date
DOCUMENTS: mycorrhizae-_a_contributor_to_soil_and_root_health (1) (66.0 KB)
ADJUVANTS AFFECT APPLE FRUIT AND LEAF CALCIUM CONCENTRATIONS
Recent trial data show that not all adjuvants are equally effective in terms of their ability to facilitate the movement of calcium into the leaves and fruit of apple following the application of calcium sprays.
DOCUMENTS: Adjuvant_calcium nitrate sprays (84.6 KB)
APPLE TREE MANAGEMENT IN SOUTH AFRICA: PRACTICAL SCIENCE
Densities for apples appear to have stabilised at around 1500 trees/ha. The predominant system currently used is a tree with a single central leader and fruiting branches directly situated on the leader. The tree is similar to the “Solaxe”, but is unique in the sense that its evolution is the result of an improved understanding of the reaction of the apple tree to a lack of winter chilling, hot growing conditions and poor soils.
DOCUMENTS: Apple Tree Management in South Africa: Practical Science.PDF (130.8 KB)
CHEMICAL THINNING OF APPLES
The removal of excess flowers or fruitlets by chemicals is an important tool to achieve regular crops of the desired size and quality specifications. Chemical thinning is often referred to as “an art rather than a science”. It must be accepted that aggressive chemical thinning programs can lead to over-thinning from time to time, but in general, with a few exceptions, our chemical thinning programs only perform approximately 60% of the total thinning job. Followup thinning by hand, as early as possible is therefore still needed.
DOCUMENTS:
CHEMICAL THINNING OF APPLES.PDF (541.1 KB)
DELAYED FOLIATION ON POME AND STONE FRUIT AND ITS CONTROL BY CHEMICAL REST-BREAKING AGENTS
Lack of winter chilling in the majority of South Africa’s deciduous fruit growing areas, is the primary cause of the phenomenon called delayed
foliation. The severity of the symptoms is related to fruit kind, cultivar, growing area, orchard slope and the number of chilling units accumulated
during the winter months.
DOCUMENTS: DELAYED FOLIATION ON POME AND STONE FRUIT AND ITS CONTROL BY CHEMICAL REST-BREAKING AGENTS.PDF (430.4 KB)
EXISTING PRE-HARVEST PREDICTIONS AND MODELS FOR BITTER PIT INCIDENCE

The earlier in the season bitter pit potential can be identified and quantified, the higher the possibility to reduce bitter pit incidence. A reliable prediction method or model will enable accurate estimations on expected bitter pit potential in an orchard. This will allow for time to apply affirmative measures to reduce possible financial losses due to bitter it in apples.
DOCUMENTS: Existing Pre-harvest Predictions and Models for Bitter Pit Incidence.PDF (142.3 KB)

CONTROLING SUNBURN: WHAT ARE THE OPTIONS?
Sunburn on apples results from a combination of high fruit surface temperature and high light intensity. Annual losses in export volumes are generally about 10-20% but can reach 50%. In this article, we review the available technologies used for sunburn control, including orchard management, evaporative cooling, Surround, Raynox® and shade netting, based on research carried out locally and internationally.
DOCUMENTS: Controlling sunburn: what are the options?.PDF (119.1 KB)
WATER STRESS – PHYSIOLOGICAL RESPONSES OF FRUIT TREES WITH SPECIAL REFERENCE TO FRUIT QUALITY IN APPLES
Water is the most abundant and, at the same time, the most limiting resource, that plants need to grow and function for the best efficiency or productivity in terms of biomass. Water is important to the physiology of plants due to its crucial role in all physiological processes and due to the large quantities that are required.
DOCUMENTS: Water stress – physiological responses of fruit trees with special reference to fruit quality in apples.PDF (107.6 KB)