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Title: Studies on seed quality and plant establishment in relation to crop production
Author: Gray, David
ISNI:       0000 0001 2436 6312
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1986
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The main theme of the submission is the role of seed source and sowing/planting method on the establishment of vegetable crops and on the uniformity of time of maturity and weight of individual plants. It is also concerned with the effect of the environment during seed production on seed quality, with the manipulation of husbandry practices during the production of seeds and during the establishment of the crop, to improve the efficiency of crop production. Work on potatoes showed how the yields of small tubers for canning whole could be increased and the season of supply extended by using particular combinations of sizes of seed tubers and seed rates to manipulate stem densities. This, the identification of a suitable cultivar and the use of a 'mini-bed' system of production were widely adopted by the industry. The number of tubers and their growth were also shown to be influenced by the method of growing and storing the seed tubers, by water supply and by changes in the supply of assimilates at the time of tuber initiation. Work on small-seeded vegetables demonstrated the relationship between variation in plant size in the subsequent crop with the methods of culture and other factors during the production of the seed. These cultural practices and the position of the seed on the plant were found to be significant sources of variation in quality between seed lots. Parallel cytological studies showed that the responses to seed-crop cultural practices were related to differences in the size of the embryo rather than that of the seed. The quality of the seed was also affected by temperature / during its development and by the drying conditions during maturation and after harvest. The volume of the ovule and embryo-sac at fertilisation and the number of endosperm cells were shown to regulate seed size in carrot. To enable growers to exercise greater control over the germination and emergence phases of growth, a technique of sowing pre-germinated seeds was developed. This system gave earlier, higher and sometimes more uniforn emergence and crop maturity than traditional systems using dry, 'advanced' or 'primed' seeds. In lettuce, high-temperature induced dormancy was identified as a major factor influencing establishment, seeds being sensitive at two stages during the germination process. Sowing pre-germinated seeds with a fluid drill overcame this dormancy in lettuce and also the effects of low temperature which delay and reduce the germination and emergence of tomato and Umbelliferous crop seeds. Studies of the effects of the number of seeds germinated at the time of sowing, radicle length, amount of gel carrier and the environment after sowing on the responses to fluid drilling enabled the components of the system to be optimised.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (D.Sc.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Agronomy