Topics:

• Key research findings
• Experimental design
• Time Series Videos

Key research findings

Quince A rootstocks with Beurre Hardy interstem (QA/BH) produce fruit earlier and set fruit well but the high crop loads increase the likelihood of needing thinning intervention to ensure adequate fruit size. Conversely, in years with low fruit set, trees with D6 rootstock may lose pack-out yield due to oversizing of fruit. At this stage, D6 can be recommended as a preferred rootstock for use with ‘ANP-0131’ due to high pack-out yields (yield of fruit 150 – 280 g) of fifth-leaf trees. QA/BH and QC/BH (Quince C rootstocks with Beurre Hardy interstem) are preferred rootstocks for ‘ANP-0118’ on the basis of yields of young trees. However, crop load management appears necessary to size fruit with these rootstocks and long-term production may be improved by use of D6. ‘ANP-0534’ performed similarly well on QA/BH, QC/BH and D6 rootstocks. Use of BP1 rootstock is not recommended with any of the cultivars due to lower yield potential.

To date, assessments of rootstock performance have focused on total annual and cumulative yield in the first three years of production. Ultimately, cultivar x rootstock combinations that set moderate crop loads with minimal interventions once trees reach full production may be more profitable than trees with a tendency to crop heavily and undersize fruit. Further investigations of long-term trends in flower density and fruit set, and desirable crop loads for each cultivar x rootstock are required to ensure maximum pack-out.

Summary results - Rootstock for blush pears

Summary of the effects of currently available rootstocks on growth, yield and quality of new red-blushed pear cultivars.

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Key messages:

• Third leaf flower cluster number, fruit number and yield of cultivars ANP-0118 and ANP-0131 were highest when grafted to Quince A and to a lesser extent, Quince C rootstocks.
• Leader height at the end of the third leaf for cultivars ANP-0131 and ANP-0534 tended to be less when grafted to BP1, Quince A and Quince C rootstocks.
• There was no effect of rootstocks on fruit colour, firmness, sweetness and maturity for each of the cultivars.

Time Series Videos: Rootstock experiments 2015 – 2020

Every few weeks photos were taken of each experiment, and produced into a video to show the resulting growth of tree canopies and fruit development.

Time series videos Trials M - Z, AC - AI

Table 1: Profitable Pears Orchard - Rootstock experiments (list of trials M - Z, AC - AI)

QA = Quince A

QC= Quince C

BH = Beurre Hardy interstem

Nij = Nijisseiki interstem

Virus = apple stem grooving virus

^{This project, AP12002 Profitable Pears: Maximising productivity and quality of new pear varieties, is funded by Agriculture Victoria with co-investment from Horticulture Innovation Australia Limited using the apple and pear levy and funds from the Australian Government}