International apple & pear research – Jun/Jul 2018

Snippets of the latest apple and pear research from all around the world covering water and nutrition; pollination, flowering and fruit-set; vigour management; and business management.

Water and nutrition

Reduced water stress

Korea Republic: A study of two apple cultivars on M9 rootstocks found that one, with more stomata and larger xylem area suffered less from water stress and had higher rates of photosynthesis. See: Comparisons of physiological and anatomical characteristics between two cultivars in bi-leader apple trees (Malus × domestica Borkh.).

Drippers versus sprinklers

USA: Apple trees subjected to deficit irrigation using overhead sprinklers have smaller fruit than deficit irrigation using drippers. See: Evapotranspiration-based irrigation systems and nitrogen effects on yield and fruit quality at harvest in fully mature ‘Fuji’ apple trees over four years.

Drones determine nitrogen

Australia: Canopy nitrogen levels of pears can be estimated from the canopy colour photographed from a drone flying over the crop. See: Remote sensing using canopy and leaf reflectance for estimating nitrogen status in red-blush pears.

Pollination, flowering and fruit set

Increased flower frost damage

USA: Global warming may lead to increased flower frost damage in cool apple growing regions if average minimum temperatures decrease in association with substantially elevated average maximum temperatures. See: Regional influences of mean temperature and variance changes on freeze risk in apples.

Improving fruit set

Brazil: The application of AVG during apple flowering in a low fruit set season increased fruit production. See: The effect of AVG and Promalin on fruit set of apple trees under adverse pollination conditions.

Dominant flowers

USA:  Gala apple trees are king flower dominant with the lateral flowers producing smaller fruit than king flowers even when the other flowers on the spur are removed to eliminate competition. See:  Positional effects on retention potential within the spur of apple (Malus × domestica) with and without competition with other fruit on the spur.

ABA on pears

China: The application of abscisic acid to pear flower buds prior to dormancy accelerated the transition of the buds into dormancy. See: Abscisic acid (ABA) promotes the induction and maintenance of pear (Pyrus pyrifolia white pear group) flower bud endodormancy.

Wild bee pollen

USA: A study of the pollen that wild bees carry has identified the importance of flowering tree species for their survival indicating that forest fragments near orchards should be preserved. See: Pollen preferences among the bee species visiting apple (Malus pumila) in New York.

Vigour management

Shoot growth differences

Brazil: Root pruning both sides of an apple tree soon after flowering has less shoot growth reduction compared to prohexadione-calcium and there is no benefit in a combined treatment. See: Root pruning and prohexadione-calcium affect shoot growth of mature vertical axis apple trees.

Growth inhibitor comparison

Brazil: Prohexadione-Ca and Trinexapac-ethyl (Moddus), applied soon after apple flowering, reduced shoot growth to a similar extent, however, Trinexapac-ethyl reduced return bloom. See:  Vigor control in ‘McIntosh’ apple trees by growth inhibitors.

Production system and quality

Ethephon to improve colour

Moldova: The application of 400 ppm Ethephon to Gala Must apple trees before commercial harvest improved skin colour development as well as crop profitability. See: Effects of Ethephon application on color development of ‘Gala Must’ apples.

Managing trees in replant soil

Korea Republic: Fuji/M9 apple trees were planted into replant soil. After five years the Solaxe system had the highest yield followed by the slender spindle system and finally the Narita system. See: Effect of three training systems on the growth and fruiting of ‘Fuji’/M.9 apple trees on a replanted site in Korea.

Temperature affects fruit weight

USA: The fruit weight of Golden Delicious apples is affected by the temperature in the first 60 days after full bloom and crop load has a major influence on fruit weight in cold seasons. See: The interactive effects of early season temperatures, crop density and rootstock on average fruit weight of ‘Golden Delicious’ apple.

Organic apple production

Hungary: Stable manure use in organic production leads to unbalanced and obstructed calcium uptake. See: Plant nutritional and environmental aspects of organic apple production in East Hungary.


Genes affecting nutrient status

USA: The two dwarfing genes in apple rootstocks have been found to have a significant effect on the nutrient status of the leaves and fruit of the scion. See: Apple rootstocks’ dwarfing loci relationships with mineral nutrient concentration in scion leaves and fruit.

Comparing rootstocks

Mexico: G16 rootstocks have a yield efficiency similar to M9T337 and the fruit and leaves have higher levels of P and K compared to trees on M9 rootstocks. See: Response of apple rootstocks to vigor, yield efficiency and leaf and fruit concentrations of NPK.

Pests and diseases

Increased Penicillium resistance

China: The application of auxin to pear fruit increases their resistance to Penicillium rot due to the induction of natural resistance processes within the fruit. See: Indole-3-acetic acid inhibits blue mold rot by inducing resistance in pear fruit wounds.   

New pear virus

Japan: A new virus of pear, pyrifolia partitivirus 2, has been identified. See: A novel alphapartitivirus detected in Japanese pear.

Controlling Alternaria

Turkey: Alternaria mali fungal growth is controlled by Iprodione, Difenoconazole, Chlorothalonil and Thiophanate Methyl. See: Determination of the effects of some fungicides on Alternaria mali Roberts (necrotic leaf spot) of apple.

In vitro virus eradication

Brazil: Shoot tips taken from tissue cultured apple rootstocks, encapsulated in alginate beads, dehydrated, immersed in liquid nitrogen, then warmed and recovered are free of viruses. See: Cryotherapy by encapsulation-dehydration is effective for in vitro eradication of latent viruses from ‘Marubakaido’ apple rootstock.

Bird nets increase insect pests

Spain: Apple trees with bird netting restricting insectivorous birds have greater populations of insect pests. See: Birds as suppliers of pest control in cider apple orchards: avian biodiversity drivers and insectivory effect.

Products and processing  

Apple extract for cut flowers

Iran: Apple extract added to vase water increased the vase life of Gerbera flowers from 9 to 20 days. See: An investigation into the potential enhancement of vase life and physiological characteristics of gerbera cut flowers by apple fruit extract and rosemary essential oils.

Cloudy apple juice

Bosnia-Hercegovina: Consumer sensory satisfaction of cloudy apple juice was improved if juice from heritage apple cultivars was blended with juice from modern commercial cultivars. See: Sensory evaluation of blended cloudy apple juices.

Vacuum drying apples

Thailand: Vacuum drying of apples speeds up the drying process, reduces fruit shrinkage, increases the number of pores, improves dried fruit crispness and aids in rehydration. See: Effects of vacuum drying on structural changes of bananas, pineapples, and apples.

Apple for scalp health

Italy: Apple procyanidin B2 applied to the human scalp increases hair growth, density and keratin content. See: Annurca apple nutraceutical formulation enhances keratin expression in a human model of skin and promotes hair growth and tropism in a randomized clinical trial.


Flesh browning during storage

Brazil: Flesh browning of Fuji apples during long-term CA storage was found to be more prevalent in fruit with less than 80 mg per kilogram of calcium. See: Multivariate analysis of mineral content associated with flesh browning disorder in ‘Fuji’ apples produced in Southern Brazil.

Early-ripening apple

Israel: Anna, an early-ripening apple cultivar with a short storage life has a high level of ethylene production and response during fruit growth and development. See: Different preclimacteric events in apple cultivars with modified ripening physiology.

Low flesh browning

Croatia: Cripps Pink apples were found to be superior to 6 other common apple cultivars for fresh-cut production due to their low level of flesh browning. See: Influence of antibrowning solutions, air exposure, and ultrasound on color changes in fresh-cut apples during storage.

Business management

Value of co-ops

The Netherlands: A study of apple co-operatives in two regions of China found that co-operative membership had a positive impact when selling to wholesalers but a negative impact when selling to small dealers. See: Cooperative membership and farmers’ choice of marketing channels – evidence from apple farmers in Shaanxi and Shandong provinces, China. 


By |June 25th, 2018|R&D updates|

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