International apple and pear research update – April 2016

Compiled by Dr Gordon Brown

International apple and pear research update snippets are sourced from abstracts of published scientific papers collated in the CAB direct database. To get the abstract related to any snippet please contact Gordon Brown on gordon@scientifichorticulture.com.au or 03 6239 6411.

Nursery and cultivars

Elite rootstocks

China: Seedlings of Malus micromalus × M9 were assessed for rooting ability; salt and alkaline tolerance; and resistance to Valsa canker – five elite rootstock lines were selected.

Cold region apples

China: To supply market demand nine early apple cultivars were tested in Huashuo, Hongjiangjun, Huayu and Zaohong and found to be suitable for the cold regions of Yunnan.

Optimal rooting

India: A study of M793 cutting length and thickness has shown that cuttings should be 35cm in length and 1.25 – 1.5cm in thickness (the thickest tested) for optimal root development.

Rootstock comparison

Romania: In the first year after grafting, trees on MM106 rootstocks produce more feathers than trees on M26 rootstocks.

Production

Biennial bearing

Turkey: GA4+7 was found to be more effective at controlling biennial bearing than ethephon in Golden Delicious trees.

Robot ID apples

China: An accurate robotic identification of apples on a tree using six colour features and seven shape features has been developed.

Apples hurt environment

China: Apple industry growth increased farmers’ incomes, but caused pollution so methods to reduce pollution and increase fertiliser use efficiency need to be adopted.

Fruit colouration

Turkey: Prohydrojasmon application to Gala and Braeburn apple trees two weeks before harvest improved the fruit red colouration.

Mulching apples

China: Mulching apple trees with straw increases the percentage of roots within 20cm of the soil surface.

Manure toxicity

China: Pot trials have demonstrated toxicity, due to addition of organic manure to the soil as a fertiliser, occurs at lower doses in sandy soils compared to loam soil for pear trees.

Helpful bacteria

India: Some of the 14 of Pseudomonas bacteria from an apple orchard soil were found to produce plant growth hormones, soil phosphate solubilising activity, and antifungal activity.

Spindle comparison

Czech Republic: For Topaz apple trees, no differences in yield efficiency or cumulative yield were found between slender spindle and modified slender spindle tree training systems.

Irrigating pears

Albania: Regulated deficit irrigation was found to have no impact on vegetative growth of three-year-old Williams pears although mulching trees had a positive effect.

Better blooming

South Africa: Benzyladenine application to two cultivars of pear had no effect on fruit size however return bloom was significantly improved.

Native bees

USA: A survey of native bees in apple orchards has identified 128 species of native pollination bees from 28 genera.

Too warm for apples

Spain: Climate change modelling indicates that winter temperatures may become too warm for reliable apple flowering close to the southern end of the French border.

Reducing sunburn

Iran: Kaolin application to apple trees reduces leaf temperature and transpiration and increases the foliar photosynthetic rate as well as reducing fruit sunburn.

Iron effects

Iran: Foliar iron application to Fuji apple trees increased total phenolic content and dry matter content of the fruit.

Disorder reduction

Turkey: Trials over three years revealed that application of GA3 or GA4+7 reduce fruit russet although GA4+7 increased the incidence of bitter pit. Regalis and ethephon had no effect on either disorder.

Pests and diseases

Leaf blotch control

India: The application of resistance inducing chemicals may provide useful control of Marssonina leaf blotch of apple.

Black spot

Belgium: A heritage Belgium apple cultivar with stable partial resistance to black spot has been used to identify nine genes associated with partial black spot resistance.

Brown rot cause

ArgentinaPhytophthora lacustris and P. drechsleri have been identified as the cause of Brown rots on pear fruit prior to harvest.

Codling preferences

USA: Codling moth egg laying preference testing of apples has shown that Golden Delicious, Fuji and Stayman are preferred cultivars while Arlet, Honeycrisp, Pristine, and Sunrise are avoided.

Reducing insects

New Zealand: The apple futures system was developed to reduce pesticide residues on fruit and maintain phytosanitary requirements, since the mid 1990s it has reduced insect loading.

New virus

Brazil: A new virus found in apple, pear and grapevines has been identified and it is proposed to call it Temperate fruit decay-associated virus.

Genes resist black spot

India: Four races of black spot were isolated from apple orchards and resistant cultivars with the RVi3, RVi6 and RVi13 genes were resistant to all four strains of the fungus.

Post-harvest

Post-harvest rot

India: Bio formulation comprising of six botanicals and cow urine have been found to be effective for the management of post-harvest rot in apples.

Residue exposure

China: Ninety three per cent of Chinese pears have pesticide residues, some above the MRL, and while not a serious public health problem there is potential for acute exposure of children to bifenthrin.

DPA on pears

India: Post-harvest application of DPA to Punjab Beauty pears reduced weight loss, spoilage, core browning, colour loss, softening and maintained fruit sugars during storage.

Bitter pit

France: A portable device is being developed to assist apple growers to manage bitter pit development and to implement sustainable thinning practices.

Storing pears

USA: Pre-harvest Retain at 60mg/L and SmartFresh both extend storage life of Starkrimson pears, however, SmartFresh inhibited ripening capacity whereas Retain did not.

Scald development

Italy: Ethylene down regulates genes important for fruit adaption to low oxygen environments as well as maintenance of low oxidant levels in the skin allowing for superficial scald development.

Bitter rot

Iran: One hundred actinomycetes isolated from apple orchard soils were screened for the control of bitter rot and six were found to have potential for non chemical control of the disease.

CO2 injury

USA: Changes in gene expression in apple skins when fruit are placed in CA are being studied to identify the cause of external CO2 injury of the fruit.

Dipping pears

China: Dipping pears in Rhodotorula mucilaginosa reduced the loss of pear fruit firmness, inhibited fruit decay and prolonged the storage duration at room temperature.

Early harvest grannies

South Africa: Granny Smith apples harvested seven days before optimal harvest had higher levels of total polyphenolics but lower levels of ascorbic acid and antioxidant capacity.

Infrared drying

Portugal: Comparing new methods of drying apples identified infrared drying as an energy efficient process which produces a high quality product.

By |April 3rd, 2016|R&D updates|

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