International apple & pear research – Dec 2018/Jan 2019

Snippets of the latest apple and pear research from all around the world covering nursery and breeding; production; robotics; pests and diseases; post-harvest; and consumer interest.


Production

Harvest timing:

Brazil: Spraying Gala apple trees with 1-MCP delayed harvest by 5.5 days and increased fruit size by 2% while spraying with AVG delayed harvest by 9 days and resulted in 7% larger fruit.

Increasing Fruit firmness

Egypt: Spraying ‘Anna’ apple trees with antioxidant organic acids 3 times at 2 weekly intervals before harvest increased fruit firmness and reduced the activity of oxidase enzymes.

Impact of netting colour

Turkey: Both red and black coloured hail netting over an apple orchard improved the photosynthetic rate and water use efficiency over pearl or flue coloured nets.

NPK impacts on soil

China: In a 28 year apple orchard fertilizer experiment NPK application increased soil organic carbon and nitrogen levels however it decreased soil C/N ratio and pH.

Pyrodwarf rootstocks tested

USA: After 12 years of growth pear trees on ‘Pyrodwarf’ rootstocks had reduced growth rates, produced smaller fruit and had more suckers than trees grown on Old Home × Farmingdale rootstocks.

Heat impact on pollen viability

China: Exposure of pear trees to 35°C prior to blossom reduces pollen viability by inhibiting pollen germination.

Age makes leaves easier to wet

China: As pear leaves age they become less hydrophobic making them easier to wet causing pesticide efficacy to improve.

Legacy of past practices

China: A survey of 46 pear orchard soils identified some orchards with heavy metal contamination due to past agricultural practices.

Dormancy genes identified

Japan: Four potential genes related to release of apple trees from winter dormancy have been identified.

 

Pests and Diseases

Early tree death identified

Germany: Athelia rolfsii (syn Sclerotium rolfsii) has been identified for recent deaths of trees within 3 months of planting.

 

Postharvest

Scald storage link

Spain: The oxidation of α-farnesene during the start of cold storage is related to the appearance of scald after long term storage of ‘Granny Smith’ apples.

Storage performance

Belgium: Apple fruit stored under RQ-DCA performed as well as fruit stored under regular CA with 1-MCP treatment.

Pear storage requirement

Italy: ‘Abate Fetel’ pears treated with 1-MCP at harvest should be CA stored for 27 weeks in order to have marketable fruit with edible texture.

Apple a day

Australia: The reduction in cardiovascular disease due to the consumption of whole apples is thought to be due to a beneficial effect on endothelial function.

Rot control alternative

Brazil: Sodium metasilicate (waterglass) application to apples in a packhouse provides equivalent control of postharvest rots compared to Iprodione.

Polyphenol antibacterial properties

China: Apple polyphenol extract from fruit thinnings has been found to possess antibacterial properties on cold stored fish.

CA offsets oxygen stress

South Africa: Pears subjected to repeated low oxygen stress (0.5%O2 for 7 days every month) followed by CA maintained firmness, colour, sugar and sensory properties without the appearance of scald.

Heritage apples study

Poland: Twenty two heritage apple cultivars were analysed for antioxidants and 26 polyphenolic compounds and three triterpenoids were identified.

Antioxidant activity over time

India: The antioxidant activity of apple slices from 13 cultivars generally decreases within 80 minutes of being cut.

Porosity link to browning

South Africa: Internal browning of apples due to high CO2 is due to affected tissue having a lower porosity restricting the supply of oxygen rather than flesh density differences.

Pear mealiness predictable

South Africa: Mealiness (dry, floury flesh) of stored pears has been found to be positively related to the fruit sugar content and can be predicted by NIR equipment.

Cider polyphenol levels

Bosnia-Hercegovina: The total polyphenols in cider are lower than in the original apple juice although some individual polyphenols (catechin, chlorogenic acid, and caffeic acid) are elevated.

Oregano role in scald prevention

USA: The postharvest application to apples with DPA or bioprocessed food-grade oregano extract reduced the appearance of superficial scald on stored apples.

Hot water dipping reduces rots

Germany: Hot water dipping of harvested apples (52°C) reduced long term storage rots of fruit by up to 65%.

Tackling browning at 30°C

New Zealand: In Asia apples are often retailed at temperatures around 30°C and this causes rapid development of internal browning in some cultivars which can be exacerbated by 1-MCP application.

Juice yeast content analysed

China: NIR analysis of apple juice can be used to determine the concentration of yeast in the juice.

Light changes provides clues

USA: Three dimensional images of apples have been composed by using structured- illumination reflectance imaging utilising phase changes in light which can discriminate between an apple bruises and the stem end of the fruit.

Temperature, size, and firmness

Netherlands: Apples sourced from higher altitudes have smaller firmer fruit at harvest.

Yeast anti-fungal properties

Argentina: The application of the yeast Rhodosporidium fluviale to apples controls Botrytis cinerea fruit breakdown, however, inactivated yeast also control the disease suggesting antifungal activity of yeast cellular components.

Anti-bacterial apple peel action

USA: Apple peel powder has been shown to restrict the growth of Bacillius cereus in food.

Internal browning causes

Japan: Internal browning of Fuji apples is associated with methanol production within the apple from the action of pectin methyl esterase during the breakdown of pectin associated with fruit softening.

 

By |January 10th, 2019|R&D updates|

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