Industry Report 2006-2007 - Apple & Pear Australia Limited (Page 7 of 15) in pdf

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apple and pear australia volume 4 2007

Biotech & Breeding

Apo1006

Ap02018

Developing systeMs for orgAnic AnD low input Apple proDuction

long DistAnce resistAnce:

A novel AnD innovAtive ApproAch to iMprove poMe fruit.

dr simon Middleton - QLd department of primary Industries of Fisheries

Dr Gowri Maheswaran - VIC

department of primary Industries, prof. M. A. Anderson, department of Biochemistry, La trobe university ,

dr e. Johnson, department of

Biochemistry, La trobe university ,Ms Mahilini ponnampalam, primary Industries research Victoria, department of primary Industries, Victoria

Apple scab (colloquially known in Australia as apple black spot) caused

130’ was selected for a commercial planting to determine strategies for

Designer apple rootstock protects itself and any scion from insect pests

tissue for upward translocation using a carrier molecule is under way.

by the fungus Venturia inaequalis, is a major disease of apples in

successful organic production of new Australian scab-resistant apples.

The rootstock of a grafted apple tree plays an important role in

Australia and throughout the world. Apple varieties resistant to apple

Organically produced apples offer one option for growers seeking higher

controlling the growth, development and fruiting of the scion. This

The efficacy of a carrier molecule in delivering a marker protein into the

scab have been bred and developed in the Department of Primary

returns, and practical production systems need to be developed to help

project aims to design an apple tree with the non-transgenic scion

phloem of transgenic apple rootstock and the detection of the product in

Industries and Fisheries, Queensland (DPI&F) apple breeding program,

satisfy increasing consumer demand for organic produce.

grafted on transgenic rootstock, which has the capability of transmitting

the non-transgenic scion grafted on transgenic apple rootstock has been

and several show promise as high quality apples with the potential to be

the desirable characters across the graft union.

explored. An effective phloem delivery system has been successfully

grown in both organic and non-organic systems.

‘RS103-130’ was successfully grown organically for four seasons in the

established and the engineered product has been detected in the non-

Stanthorpe district of southern Queensland, where up to 12 primary

Communication between the stock and the scion of a grafted tree

transgenic parts of the grafted apple plant.

One of these varieties is ‘RS103-130’, which matures mid-season (six

infection periods for apple scab can occur during the spring and early

operates through the vascular system, which is the conduit connecting

to eight weeks after ‘Royal Gala’), has exceptional shelf-life and is juicy

summer. This region is one of the more marginal apple growing areas

the two cultivars through the graft union.

Research is under way to optimise delivery of the pest or disease control

with a sweet, low-acid and mild flavour. As part of this project, ‘RS103-

of Australia, characterised by sandy soils and a warm, summer rainfall

factor to the grafted non-transgenic scion. In the longer term, the

climate. With appropriate strategies now developed to organically

Recent discoveries have revealed a novel role for phloem, which is one

modification of rootstocks offers greater potential to the apple and pear

produce ‘RS103-130’ apples in Queensland, it is highly likely that this

of the two types of tissue present in the vascular system, in terms of the

industries than scion modification, provided that transgenic rootstocks

can also be achieved in other apple growing regions of Australia which

transport and delivering of information to distantly located organs. This

can transfer the molecule to scions. An additional advantage of this

contend with fewer environmental, pest and disease pressures.

provides a unique opportunity to investigate long distance transport of

approach is that the modification of only a few rootstocks is required

macromolecules from the rootstock into the scion of a fruit tree, through

to confer benefit to many different scion varieties. This research could

Australia’s first crop of organically grown ‘RS103-130’ scab resistant

both the vascular system, and from cells of surrounding tissues into the

provide a novel technique for management of insect pests of pome fruit

apples was produced in March 2006, as part of this project. Some of

vascular system.

that is more marketable to growers and consumers than transforming

these apples were marketed through an organic wholesaler in Sydney,

the scion itself.

receiving an average price of $37 for first grade and $32 for second

The current work aims to capitalise on the long distance transport

grade fruit per 12 kg two-layer carton. Customer feedback was excellent

mechanism by transforming rootstocks in such a way that the pest

Funding sources: HAL Commonwealth, ApAL levy and department of primary

and the apples sold quickly. Returns in 2007 were even higher, and up to

control product will be transferred into the phloem for transport into the

Industries, Victoria.

$60 per 12 kg two-layer carton.

scion through the graft union.

The robustness of the scab resistance of ‘RS103-130’ has been

Most pest control agents are proteins, compounds that are not

demonstrated in the field, with no apple scab occurring on trees or fruit

readily translocated in the phloem without the action of a “carrier

of ‘RS103-130’ despite the presence of apple scab on ‘Galaxy’ trees

molecule”. Investigation into the translocation of pest or disease

planted as a commercial standard within the organic block.

controlling protein from the site of synthesis and into phloem

A second, ongoing component of the project consists of replicated high

density planting system trials for four scab-resistant apple selections,

including ‘RS103-130’. These are planted at Applethorpe Research

Station (ARS), and include evaluation of a range of rootstocks (M.9,

Ottawa 3, M.26, MM.102, MM.106) and tree densities (1666 - 5925

Harvesting scab-resistant ‘rs103-130’ apples from a V-trellis system

trees/hectare). The oldest trees were in their fifth leaf in 2006/2007.

Early yields and packouts have been excellent, and yields are expected

to further improve significantly as the trees reach their full bearing

potential. Of particular promise is that fruit size of ‘RS103-130’ averages

200 g or higher in most systems, despite heavy crop loads.

In a comparison of soil characteristics beneath sugar cane mulch in

the organic orchard, and in the herbicide strip beneath conventionally-

managed trees in an adjacent block of apples, biological activity was

greater, soil temperature was reduced, and water infiltration increased

40-fold beneath the sugar cane mulch. The improved infiltration is

particularly important, as much of the rainfall received in apple growing

regions of Australia occurs as high intensity storms. The potential effects

of soil management strategies on soil health, water use efficiency and

managing drought requires further investigation, and is applicable to

both organic and conventional systems of apple production.

An organic apple production guide has been produced which details

strategies for successful organic production of scab-resistant apples

in Australia. It was developed using the results of trials conducted in

this project, and incorporation of the principles outlined in the National

Standard for Organic and Bio-Dynamic Produce.

Four-year-old trees of a scab-resistant apple planted at 3333 trees/ha

apple and pear australia volume 4 2007 page

Industry Report 2006-2007 - Apple & Pear Australia Limited Page 7

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