Mma. Elballa et Dj. Cantliffe, ALTERATION OF SEEDSTALK DEVELOPMENT, SEED YIELD, AND SEED QUALITY IN CARROT BY VARYING TEMPERATURE DURING SEED GROWTH AND DEVELOPMENT, Journal of the American Society for Horticultural Science, 121(6), 1996, pp. 1076-1081
The effect of temperature on seedstalk development, seed yield and qua
lity in carrot (Daucus carota L.) was investigated in growth chambers
at constant day/night temperatures of 33/28, 28/23, 25/20, 23/18, 20/1
5, and 17/12 degrees C. Days to flowering, seedstalk height, number of
umbels, and seed yield decreased linearly with increasing temperature
from 17/12 to 33/28 degrees C. Continuous high temperature (33/28 deg
rees C) had a detrimental effect on germination as measured by a stand
ard germination test and an accelerated aging test. Optimum germinatio
n of the progeny occurred at 20/15 degrees C; how ever, germination ra
te tvas faster when seeds matured at 23/15 degrees C. Seeds that devel
oped at 33/28 degrees C produced seedlings with the lowest vigor, whil
e those which developed at 20/15 degrees C produced seedlings with the
highest vigor. Brief exposure of plants to 33/28 degrees C during ant
hesis or early seed development was as detrimental to seed yield as co
ntinuous exposure to 33/28 degrees C. Exposure to high temperature (33
/28 degrees C) during late seed development had less effect on seed yi
eld, and seed (quality was improved. Progeny vigor was reduced greatly
, seed development at continuous high temperature (33/28 degrees C), b
ut was unaffected by brief exposure to 33/28 degrees C at anthesis, ea
rly, or late in seed development. These results suggest that high (33/
28 degrees C) day/night temperatures during pollination, fertilization
, or early stages of seed development can greatly reduce carrot seed y
ield and seed quality.