Influence of growth conditions on freezing tolerance of wheat.
1995
Abe J. | Yoshida M. | Moriyama M. | Shimosaka E.
Seasonal changes in freezing tolerance in winter wheat were examined under different growth conditions. Our results obtained from a growth room test indicated that it is necessary to raise wheat plants at optimum growth temperatures for at least three weeks, followed by hardening for five weeks in order to exhibit maximum hardiness. This hardiness corresponded to that at wintering period in the field experiment in the moderate autumn season when subzero temperatures were rare before the establishment of lasting snow cover. This also suggests that wheat needs subzero temperatures in the latter hardening period to display its hardiness potential, as stated by Kacperska-Palacz (1978). Plant dry weight hardly affected freezing tolerance, so that plants were small due to late seeding or colder autumn showed similar tolerance to that of large plants. PI 173438, snowmold resistant but less tolerant to freezing, often showed the greatest plant weight. Water content changed with freezing tolerance, but Valuevskaya, the hardiest cultivar, did not always have the smallest amount of water in its tissues. Water content in Chihokukomugi, moderately freezing-tolerant cultivar, was greater than in PI 173433 in all samples. This shows that water content does not necessarily correlate with freezing tolerance.
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