Developmental responses in tetraploid wheat (Triticum turgidum)

Abstract

Nineteen lines of tetraploid wheat (Triticum turgidum) were examined for the presence and strength of developmental responses in the field during 1980 and 1981 and compared with lines of known vernalization and photoperiod responses in the hexaploid wheat (Triticum aestivum). Five of them had stronger vernalization responses than the winter habit hexaploid line cv. Triple Dirk C. Strong vernalization response of the tetraploids was usually associated with photoperiod insensitivity and vice versa although several lines had a combination of high photoperiod sensitivity and moderate levels of vernalization response. Compared with hexaploids the tetraploids exhibited much more variation in spikelet number per head following vernalization treatment which was less marked in some of the domesticated lines. Speculations are made on the genetic control of vernalization response in tetraploid wheat and the possible significance of greater stability in the expression of spikelet number in the evolution of wheat.