Seed production of lettuce under plastic in a warm climate in relation to sowing time and gibberellic acid application
2001
A:PS
Details
Title
Seed production of lettuce under plastic in a warm climate in relation to sowing time and gibberellic acid application
Publication Date
2001
Call Number
A:PS
Summary
Cos (cv. Parris Island), butterhead (cv. White Boston), looseleaf (cv. Grand Rapids) and crisphead (cv. Great Lakes) lettuce were sown in autumn, winter and spring and the plants were cultivated for seed under plastic cover during 1996-98. The seed yield of all cultivars was significantly higher from the autumn sowing in comparison with the winter and spring sown crops. Differences in seed yield related to the longer period of vegetative growth from the autumn sowing, which resulted in a significantly higher head weight prior to bolting. The low seed yield of spring-sown crops resulted from premature bolting due to the warm climatic conditions prevailing at the early stages of plant growth. The application of gibberellic acid at 30 ppm (as foliar spray) at the 8-leaf stage promoted bolting, but only in the autumn sown crops of Parris Island and Grand Rapids did this bring about a significant increase in seed yield. The application of gibberellic acid at head maturity increased the height of the seed stalk, as did gibberellic acid application at the 8-leaf stage, but did not affect seed yield. Unlike field grown seed crops in cooler climates, where spring sowings are favoured by a progressive increase in ambient temperature up to about 25?, under the warm climatic conditions of southern Greece, autumn sowing is indicated to avoid premature bolting.
Journal Citation
v.14(1):15-23, PLANT VARIETIES & SEEDS
Contact Information
harvest@worldveg.org
Record Appears in
Research > Published Articles