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Title: A study of some factors affecting tuber number in Solanum tuberosum L.
Author: Gray, David
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1969
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A series of field experiments were carried out to investigate the effects of differences in the previous history of the mother crop, sprout number, sprout development and in the environment in the early stages of post -emergence growth on stem and tuber production. 1. There was no effect of sprouting in the winter preceding the production of the mother crop, or burning off the mother crop on sprout, stem or tuber production in the current season in either Arran Pilot or Majestic. 2. Delay in setting up previously cold -stored tubers to sprout resulted in an increase in sprout and mainstem number in both varieties. Early- sprouted tubers showed a greater degree of lateral- branch development of the sprout and mainstem than late -sprouted tubers. The response in tuber number and yield varied from year to year but, on average, late -sprouting produced more tubers than unsprouted seed: 10% more in Arran Pilot and about 3% more in Majestic. Late- sprouted seed usually produced more tubers than early- sprouted seed. Where crops matured naturally, yields at harvest in both sprouted and unsprouted seed were similar. In 1965 tuber bulking rates in unsprouted seed were not constant and appeared to show changes in rate associated with the pattern of foliage growth and the prevailing weather conditions. 3. Efforts to induce differences in the number and type of lateral branches on the sprout and thus stem and tuber production in Arran Pilot, by clipping off the apex of the sprout at different stages of development, were not successful. An increase in an index of sprout development (the number of lateral branches + sprouts per tuber) led to an increase in stem numbers at ground level and tuber number but the relationship was not a close one. It was difficult to induce lateral - branch development of the sprout in Majestic. Although an increase in the number of lateral stems led to an increase in tuber number this was not as large as an increase per stem as from a unit increase in mainstem number. 4. It was clear from the results of a planting date experiment and a shading experiment that differences in tuber number occurred irrespective of changes in mainstem number. It was suggested that these differences were brought about by differences in the environment, particularly soil water content, light intensity and air temperature, at the time of tuber initiation. 5. It was argued that differences in the response in tuber number to sprouting from year to year could be related to differences between the treatments in 1) lateral -branch development of the sprout at planting, and 2) the environment at tuber formation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available