EARLY RESULTS WITH THE VERY DWARFING APPLE ROOTSTOCK, M 27

In a trial, planted at Ballygagin in 1976, comparing trees of Golden Delicious on rootstocks M 27, M 9 and interstocks 27/26, 9/26, 27/106, 9/106, trees on M 27 were the most efficient producers by 1979, as indicated by the cumulative production per unit of cross-sectional trunk area. M 9 was next most efficient followed by 27/106, 27/26, 9/106. All trees were grown as spindles.

In a second trial, planted in February 1977, Golden Delicious and Bramley's Seedling on M 27, were planted in four-row beds separated by 3,5 m alleyways. Golden Delicious trees were planted in rows 1,5 m apart with 0,5 m and 1,0 m spacings in the rows. Bramley's Seedling trees were also planted in rows 1,5 m apart, with 1,0 m and 1,5 m spacings in the rows. These spacings gave tree populations of 10 000 and 5 000 per ha for Golden Delicious and 5 000 and 3 333 per ha for Bramley's Seedling.

In 1978, nineteen months from planting Golden Delicious cropped at 17,5 tonnes per ha at the higher tree density and 6,6 tonnes at the lower. In 1979 corresponding yields were 29,2 and 18,2 tonnes. Fruit size was satisfactory. Bramley's Seedling, yielded 5,4 and 4,2 tonnes per ha for the two densities, in 1978, and 6,0 and 2,7 tonnes per ha in 1979.

Trees of both cultivars, that were feathered at planting, yielded 50 % more fruit per tree, in 1978, than non-feathered trees. Trees in this trial were pruned to give a flat relatively shallow canopy, as suggested by Preston. To date no suckering has been observed.