Apple cultivar and rootstock performance at Lenswood, South Australia

Abstract

In 1990 a trial was established at Lenswood, South Australia (34º57'S) to assess the performance of the apple cultivars ‘Royal Gala’, ‘Red Fuji’ (clone Naga Fu 2), and ‘Braeburn’ planted at 1250 trees/ha on the 6 rootstocks, M.9, Mark, Ottawa.3 (O.3), M.26, MM.106 and MM.111. This paper presents 9 years results from this trial, in addition to preliminary results from a subsequent trial planted in 1995 to assess the performance of ‘Pink Lady’, ‘Sundowner’, ‘Galaxy’ and ‘Red Fuji’ (clone Naga Fu 6) planted at 2000 trees/ha on O.3, M.26, MM.102, M.7, MM.106 and M.9 (‘Pink Lady’ only). The results from these trials and their implications for orchard design are discussed in terms of the light interception, leaf area index (LAI) and tree canopy volume of selected cultivar x rootstock combinations. O.3 and M.26 have performed particularly well, however O.3 has several attributes (advanced fruit maturity, virus susceptibility, propagation problems) that will influence its commercial use in Australia. Despite the good performance of Mark rootstock, concerns over soil line swelling and commercial availability will hinder its commercial use in Australia. The insufficient canopy volume of M.9 has led to changes in the pruning and crop load management of trees on this rootstock in South Australia. The excessive size and vigour of trees on MM.106 and MM.111 makes them unsuitable rootstocks for medium and high density orchards in South Australia. Trees of ‘Red Fuji’ on Mark and MM.111 have shown little tendency towards biennial bearing, whereas on M.9, M.26 and MM.106 (particularly) ‘Red Fuji’ trees have had marked annual fluctuations in yield. Braeburn has several major problems (vigour management and susceptibility to sunburn and bitter pit) which have restricted its commercial development in the warmer Australian production regions.