Maluscv. Baskatong as an indicator of pollen spread in intensive apple orchards

Abstract

SummaryThe Malus cv. Baskatong, possessing a dominant gene for red leaf colour, was used to assess the range of a pollinizer in intensive apple orchards. In 1980 in the centre of each of six orchards, a Baskatong pollinizer was planted. All orchards had more cultivars to provide for cross-pollination. For three to seven years, seeds were gathered from trees surrounding the ‘Baskatong’ pollinizer at ten distances from 2.5 to 40 m and in 8-12 directions. After stratification, the seeds were germinated in a glasshouse and green and red seedlings were counted. ‘Baskatong’ pollen was tested for suitability by controlled hand pollinations on six apple cultivars. Flowering periods of ‘Baskatong’ and all of the apple cultivars involved were assessed over three years. ‘Baskatong’ pollen gave good fruit and seed. The ‘Baskatong’ flowering period did not fully cover those of the apple cultivars, because its bloom period was shorter. Nevertheless, red seedlings arose from the seed samples in all orchards, although not in all years. The percentages of red seedlings found were low except, in a few cases, close to the pollinizer, probably because of the adequate cross-pollination. There was no distinct directional effect, but with increasing distance from the pollinizer the percentages of red seedlings declined sharply. Although red seedlings were occasionally found as far as 40 m from the ‘Baskatong’, most occurred within a circle with a radius of 5 m. In one orchard the upper limit of the radius was about 15 m, probably because the pollinizer tree was larger than those in the other orchards. The implications of the findings for orchard lay-outs and pollinizer siting are discussed, taking a circle with a radius of 5 m as an effective range.