Research

Rootstocks and Nursery Tree Quality

    Finding more precocious and productive rootstocks adapted to South African conditions is integral to our orchard of the future vision. For this reason, various pome and stone fruit rootstocks are evaluated in an increasing number of industry trials in commercial orchards.

    New apple rootstock evaluation sites were planted to dwarfing rootstocks at three locations in the Highveld region where Western Cape results are not applicable due to the milder summer climate, planting under nets and fertile soils. Louterwater Granny Smith trees on rootstocks varying in vigour were planted in two production regions with warm winters to assess their effect on bud break and flower synchronization. Together with a Granny Smith trial planted in 2022 in the Langkloof, these plantings will also be used to assess the effect of rootstock on green colour development.

    Other rootstock research is aimed at characterising new rootstocks in terms of adaptation and disease and pest tolerance. Various projects are evaluating the susceptibility of rootstocks to Phytophthora, Rosellinia, woolly apple aphids, plant parasitic nematodes and replant disease. A new project was initiated to study the cause of galls on apple nursery trees and rootstock susceptibility to crown gall. Another new project will be comparing the performance of tissue culture-derived apple and stone fruit trees against those produced from layers or cuttings, respectively.

    Prof Stephanie Midgley determined that trees on dwarfing apple rootstocks are not necessarily more sensitive to water deficit than trees on more vigorous rootstocks. Trees on dwarfing rootstocks had a much lower water requirement on a hectare basis and had a much higher water productivity, i.e., Rand income generated per cubic meter water transpired. Dr Xolani Siboza finalized a report on a rootstock evaluation trial consisting of adjacent more dwarfing and less dwarfing plantings at three locations with Fuji as scion. Rootstocks from the Cornell Geneva programme like G.778, G.228 and G.202 outperformed industry standard rootstocks.

    Chad van Wyk completed two peach/nectarine and two plum rootstock evaluation trials. The results of these trials will be incorporated into the stone fruit rootstock tables first published in issue 6 of the Fresh Quarterly (www.freshquarterly.co.za).

    EXPERTISE: ROOTSTOCK AND NURSERY TREE QUALITY WORKGROUP | ROOTSTOCK EVALUATION COMMITTEE

    Research Team

    • Prof Wiehann Steyn
    • Dr Xolani Siboza
    • Dr Iwan Labuschagne
    • Prof Stephanie Midgley
    • Dr Nigel Cook
    • Mr Tristan Dorfling
    • Prof Adele McLeod
    • Mr Chad van Wyk
    • Mr Wouter Visser
    • Ms Lindsay Muchena – PhD student
    • Ms Buhle Ngidi – MSc student
    • Mr Anton Broeksma – MSc student

    Projects list

    • Evaluation of apple rootstocks representing three vigour classes in three growing areas of South Africa. (T Dorfling)
    • Evaluation of apple rootstock cultivars for woolly apple aphid resistance (M Addison)
    • Evaluation of apple rootstocks against apple replant disease on ‘fumigated’ and ‘non-fumigated’ soil (T Dorfling and A McLeod)
    • Evaluation of pear rootstocks on different scions (T Dorfling)
    • Evaluation of pear rootstocks for Packham’s Triumph at Jackal River Farm, Vyeboom, for Forelle at La Plaisante, Wolseley, and for Cape Rose at La Plaisante, Wolseley (T Dorfling)
    • Evaluation of new apple rootstocks representing three vigour classes (Môrester and Oak Valley) (T Dorfling)
    • Evaluation of new apple rootstocks representing two vigour classes in two growing areas (Molteno, Bokveldskloof & Oewerzicht) (T Dorfling)
    • Apple rootstock influence on Granny Smith scion growth, productivity and fruit green colour (T Dorfling)- see Dormancy
    • Growth synchronisation of stone fruit rootstocks and scions with different chilling requirements (C van Wyk) - see Dormancy
    • New apple rootstock plantings in the Highveld region (T Dorfling)
    • Evaluation of apple rootstocks tolerance against specific apple replant disease (SARD) (T Dorfling and A McLeod) - see Pre-and-Post-Harvest Pathology
    • Tolerance of apple rootstocks against Phytophthora root rot (A McLeod and L Moyo) - see Pre-and-Post-Harvest Pathology
    • Effect of mulching, compost and rootstock genotype on white root rot of apple (A McLeod) - see Pre-and-Post-Harvest Pathology
    • The stability of productivity and fruit quality traits of 'Fuji' apples on different rootstocks [Abstract]
    • Evaluation of peach and nectarine rootstocks for the South African fruit industry in association with IP owners at Vaalwater. (C van Wyk) [Abstract]
    • Evaluation of plum rootstocks for the South African fruit industry in association with IP owners at Simondium. (C van Wyk) [Abstract]
    • Evaluation of plum rootstocks for South African Industry: Robertson planting. (C van Wyk) [Abstract]
    • Evaluation of peach rootstocks for South African fruit industry: Rawsonville planting. (C van Wyk) [Abstract]
    • Sensitivity of various apple rootstocks to water stress. (S Midgley) [Abstract]
    • Apple rootstock evaluation and interstem combinations at Helderwater in the Langkloof and at Oak Valley and Breëvlei in Grabouw (X Siboza and B Ngidi)
    • Quantifying the role of vapour pressure deficit in the development of lenticel breakdown in Braeburn apples (D Viljoen and E Lötze) [Abstract]
    • Establishing quantitative relationships between water relations, growth, yield and quality of high-performing commercial apple orchards (S Midgley) – See Irrigation and nutrition [Abstract]
    • Development of a best practice guideline for the construction of dwarfing rootstock support structures (W Visser) – See Farming Technology [Abstract]
    • Screening of apple rootstocks for resistance against the most prevalent Pratylenchus species affecting orchards in South Africa (R Knoetze) – See Nematology [Abstract]

     

    << Back to Previous Page
    Back To Top