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STUDIES IN THE PHYSIOLOGY OF THE ONION PLANT
Author(s) -
HEATH O. V. S.,
HOLDSWORTH M.,
TINCKER M. A. H.,
BROWN F. C.
Publication year - 1947
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1947.tb06383.x
Subject(s) - bolting , ripening , biology , yield (engineering) , sowing , horticulture , agronomy , materials science , metallurgy
A wide range of factorial experiments at Wisley on onions grown from sets included combinations of the factors: storage of sets at high and low temperatures during the winter, variety, set size, set planting date and nitrogen manuring. Bolting, yield and ripening data are recorded. One experiment was repeated in Scotland and Northumberland where early ripening was expected to be more important than at Wisley. In general, all the factors enumerated except nitrogen manuring had large effects on bolting and yield, and storage temperature had a large effect on the time of ripening. Varieties can be selected such that large sets may be used without appreciable loss by bolting and maximum yield thus secured. Storage temperatures of from 20 to 24° C., applied for about 14 weeks from October onwards, can be used to control bolting and to increase the yield even of non‐bolting strains by delaying ripening and so extending the growth period. Storage at 24° C. is more effective in preventing bolting than the lower temperatures, but 20° C. is probably more effective in delaying ripening. High‐temperature storage is probably unsuitable for sets to be planted in the north and west of Great Britain because of the difficulty of ripening the bulbs. For these districts low‐bolting strains are therefore essential. Storage at o° C. gives only a partial control of bolting and has no effect on ripening. Late planting of sets, although very effective in controlling bolting, results in a substantial loss of yield and, therefore, is not a practical measure. Nitrogen manuring had practically no effect on yield and could not be used to prevent the loss of yield caused by late planting.