International apple & pear research – April/May 2017

Breeding and nursery

Top four apples

Russia: After a 60-year breeding program there are four apple cultivars that are highly productive with desirable high quality fruit that store well. See: Apple assortment replenishment in central regions of Russia.

Low winter chill genes

Israel: For breeding of low winter chill apple trees a region of chromosome 9 has been identified that contains some genes that impart a low winter chill character. See: A unique haplotype found in apple accessions exhibiting early bud-break could serve as a marker for breeding apples with low chilling requirements.

Resistant heritage apples

Romania: Twelve heritage apple cultivars were studied for pest and disease resistance and high resistance was found in five cultivars which can be exploited in breeding programs. See: Evaluation of resistance to pests and diseases of some old apple varieties.

Production

Less water, less biennial bearing

France: Seven years of water stress to Granny Smith trees reduced the number of side branches and increased the transition of vegetative buds to floral buds causing a reduction in biennial bearing. See: The impact of long-term water stress on tree architecture and production is related to changes in transitions between vegetative and reproductive growth in the ‘Granny Smith’ apple cultivar.

Photos for nitrogen

China: A method of correcting for scattered light has been developed to improve prediction of foliar nitrogen content from photographed apple tree canopies. See: Improve the prediction accuracy of apple tree canopy nitrogen content through Multiple Scattering Correction using spectroscopy.

Analysing ancient apple seeds

Italy: The DNA from apple seeds, found in Roman amphorae preserved since the first century, has been extracted and undergone genome analysis. See: Archaeobotanical reconstructions of vegetation and report of mummified apple seeds found in the cellar of a first-century Roman villa on Elba Island.

Robotic harvesting

USA: The robotic harvest efficiency of apples can be improved if the robot removes easily detectable apples prior to recapturing an image and harvesting the newly detected apples. See: A hierarchical approach to apple identification for robotic harvesting.

Crab apple pollinators

India: Four crab apple cultivars were tested for their pollination efficacy of five apple cultivars and Malus floribunda was significantly superior to the others. See: Pollination compatibility among different apple cultivars under Kashmir conditions.

Nashi pollen dispensers

Belgium: Nashi pollen in a dispenser at the front of bumble bee hives is an effective way of pollinating Conference and Comice pears. See: Introduction of new tools to improve pollination in European pear orchards.

Reduce fruit drop

Turkey: While zinc (0.3% ZnSO4) sprays reduce pre-harvest fruit drop, they advance apple fruit maturity, mixing it with AVG (Retain) increased fruit titratable acidity, phenolics and antioxidant capacity. See: The effects of aminoethoxyvinylglycine and foliar zinc treatments on pre-harvest drops and fruit quality attributes of Jersey Mac apples.

Reduce emissions

Canada: Nitrous oxide greenhouse gas emissions from orchards can be reduced by less frequent irrigation and the use of mulch, 50% of emissions occur during pre­-season freeze­thaw cycles. See: Effect of drip irrigation frequency, nitrogen rate and mulching on nitrous oxide emissions in a semi-arid climate: an assessment across two years in an apple orchard.

Pests and diseases

Neonics and codling moth

Italy: The neonicotinoid, Clothianidin, has been shown to be very effective against codling moth and its toxicological and ecotoxicological profile indicate it would be useful in IPM programs. See: Clothianidin (Dantop® 50 WG): evaluation of its effectiveness against codling moth on apple.

Keeping good mites

Italy: Trials with the new insecticide emamectin benzoate have shown the material has minimal impact on beneficial phytosidae mites. See: Selectivity of emamectin benzoate (Affirm®) towards Phytoseidae beneficials on grapes and apples.

Mirids and deformed fruit

Italy: The presence of Rhyncota mirids in pear orchards has been found to coincide with the appearance of deformed fruit. See: Preliminary results of an inquiry on Rhyncota Miridae populations in pear orchards of Reggio Emilia Province.

Mealy bug impacts

Italy: Comstock mealy bugs have been found to be responsible for a heavy honeydew in pear fruit calyx cavities. See: Investigations on Comstock mealybug on pear in Modena Province (Italy).

Alternaria leaf blotch

Australia: Alternaria leaf blotch infection occurs from 20 to 110 days after bloom (DAB) while fruit infection occurs at about 100 DAB and control strategies should target these times. See: Timing of infection and development of Alternaria diseases in the canopy of apple trees.

Green apple aphids

India: The predators Episyrphus balteatus, Eristalis tenax, Eristalis interruptus, and Sphaerophoria scripta are found to have equal potential for the control of green apple aphids. See: Functional response of four syrphid predators associated with green apple aphid (Hemiptera: Aphididae) in laboratory.

Phytoplasmid detection

Albania: Spring time detection of phytoplasmids in apple trees is optimal as they are detectable in all plant parts due to systemic spreading at this time of year. See: Amount of DNA extracted from different tissues of apple trees in springtime can be used to describe the level of infection.

Mealy bug detection

India: Live crawlers of Comstock mealy bugs have been detected on Chinese fresh pears during import quarantine inspections. See: Comstock mealy bug (Pseudococcus comstocki), a native pest of the Chinese ecosystem intercepted in imported pears and quince fruit in India.

Biochar setback

Germany: The incorporation of biochar­compost or fertiliser into the planting hole did not overcome apple replant disease with biochar­compost actually reducing tree growth. See: Biochar-compost substrates do not promote growth and fruit quality of a replanted German apple orchard with fertile Haplic Luvisol soils.

Post-harvest

Assessing pears internally

Poland: MRI can be used on stored pears to assess internal condition as it can identify flesh water content, volume of brown tissue and voids in the flesh. See: Application of low-field MRI for quality assessment of ‘Conference’ pears stored under controlled atmosphere conditions.

Reducing Listeria

Spain: Listeria was inoculated onto freshly cut pear surfaces and after two days their ability to infect the human gut (human pathogenicity) was dramatically reduced. See: Exposure to minimally processed pear and melon during shelf life could modify the pathogenic potential of Listeria monocytogenes.

Superficial pear scald

Spain: Superficial scald in pears develops differently to apples with cultivar susceptibility not related to accumulation of α-farnesene but to accumulation of CTols. See: Unravelling the physiological basis of superficial scald in pears based on cultivar differences.

Diffuse flesh browning

USA: Diffuse flesh browning of Honeycrisp apples is associated with lower air temperatures during active fruit growth on the trees.  See: Diffuse flesh browning in ‘Honeycrisp’ apple fruit is associated with low temperatures during fruit growth.

Stabilising pectin

Poland: Ultrasound treatment of apples causes solubilisation of pectin and a reduction in cell wall stiffness. See: Changes in cell wall stiffness and microstructure in ultrasonically treated apple.

Killing codling larvae

USA: Three to five percent nitric oxide over 24 hours to apples at 2°C under ULO killed codling moth eggs and larvae with no effect on fruit firmness or colour. See: Efficacy of nitric oxide fumigation for controlling codling moth in apples.

Ehtylene and Jonathons

Ukraine: After SmartFresh™ application most apple cultivars slowly increase their ethylene production to low levels although Jonagold rapidly increases its ethylene production rate after three months of storage at 2°C. See:  Ethylene emission of apples treated with 1-methylcyclopropene during storage.

Grading with spectroscopy

Italy: Reflectance spectroscopy at 670nm (chlorophyll) on stored Braeburn apples can be used to grade apples for firm, crisp and juicy and five other wavelengths can detect mealiness. See: Relationship between texture sensory profiles and optical properties measured by time-resolved reflectance spectroscopy during post-storage shelf life of ‘Braeburn’ apples.

Health and consumer interest

Hot seasons, poor flavour

Finland: Over several seasons trained sensory panels detected that apple fruit flavour and aroma was poor in hot growing seasons, particularly for early ripening cultivars. See: Annual variation in sensory characteristics of seventeen apple cultivars.

Apples and diabetes

Japan: A possible mechanism of apple procyanidin amelioration of type 2 diabetes has been identified. See: Oral administration of apple procyanidins ameliorates insulin resistance via suppression of pro-inflammatory cytokine expression in liver of diabetic ob/ob mice.

Lower allergen apples

Italy: A study of 24 apple cultivars, using allergic consumers, has identified that heritage apples as a whole have lower allergenic potential to modern cultivars. See: Old apple (Malus domestica L. Borkh) varieties with hypoallergenic properties: an integrated approach for studying apple allergenicity.

Processing

Better juice extraction

Poland: Enzymatic treatment or freezing and thawing crushed apples improves juice and antioxidant extraction efficiency. See: Application of freezing and thawing in apple (Malus domestica) juice extraction.

Cut apple treatment

Italy: Pulsed electric field treatment of freshly cut apple slices can lead to loss of cell viability causing reduced rates of respiration with impacts on product quality. See: Metabolic response of fresh-cut apples induced by pulsed electric fields.

Cut apple coatings

Argentina: Coating fresh cut apple cubes in ascorbic acid/calcium chloride, followed by pectin coating and pulsed light maintained cube colour, antioxidant potential and reduced microbial spoilage for 14 days. See: Effects of pulsed light treatments and pectin edible coatings on the quality of fresh-cut apples: a hurdle technology approach.

Grading for cut fruit

Italy: Fruit maturity affects fresh cut apple texture and in order to obtain a homogeneous product spectroscopy at 670nm can be used to grade fruit prior to cutting. See: Influence of maturity degree, modified atmosphere and anti-browning dipping on texture changes kinetics of fresh-cut apples.

Acknowledgement

This article has been prepared as part of the National apple and pear grower communications program that is delivered by APAL and funded by Horticulture Innovation Australia Limited using the research and development apple and pear levy and funds from the Australian Government.

By |April 1st, 2017|R&D updates|

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