Observations on Plant and Tuber Growth of Potato in Alaska

Abstract

Several phenotypic characteristics that otherwise would be diffult to observe under field conditions in temperate-zone latitudes are amplified in Alaska at 61° 34' and north. At this latitude, the growing season for potato is marked by cool temperatures at its beginning and end as well as long daylight periods. Characteristics that have been observed include: rosetting, skirts-up, leaf color change, wet leaf, perforated leaf, fasciation, inverted leaf, flowering, stolon plant production, double tuber, second growth, stolon extension, tuber constriction, eye depth, heat sprout, cracking, tuberization, frost resistance, fruit set, sprout tuber, and sprout necrosis. Stolon plant production and tuberization have been noted for samples of 27 Solanum species. Numerous plant- and tuber-growth manifestations are shown. Seed tubers of potato varieties stored over winter under identical conditions manifest significant differences in their capacity to generate a top following field planting. Stolon growth, stolon plant development, and tuberization indicate that a delicate physiological balance exists in some clones relative to the Alaskan environment. Changes in tuber shape, eye depth, and second growth are manifestations of environmental changes of rather short duration. Possibly heat sprout results from damage to the potato by particular foreign bodies. Iopride showed the least rosetting and this character is conspicuous in some of its progeny. Leaves of some clones dosed in toward the stem during light conditions approximating twilight. A few clones exhibited inverted leaf as a growth response to low light intensity while two clones lost their green color at the apex. Perforated leaf of potato and fireweed in the Matanuska Valley has been traced to aphid-feeding injury. Plants grown from tubers of potatoes with perforated leaves did not exhibit the perforated-leaf condition.