Effect of temperature on the growth of wheat. II. 'Grass-clump' dwarfs and dwarf varieties

摘要

Six F1"grass-clump" hybrids, two "grass-clump" selections, three normal varieties (Timstein, Redman, and Federation), and three dwarf varieties (Sonora 64, CB 151, and Norin 10) were grown in growth cabinets under 1200ensp;ft-c of continuous light at various temperatures. The normal and dwarf varieties grew tallest at 16 deg;C and produced maximum shoot and seed yields at 16ndash;19 deg;C.The Marquillo times; Timstein "grass-clump" dwarf selection (F6) tillered extensively in temperature regimes that included 16ensp;h of 16 deg;C in 24ensp;h or 16ensp;h of 21 deg;C and 8ensp;h of 16 deg;C. Fertile tillers were produced in all temperature regimes except 16 deg;C. Growth at temperatures above 21 deg;C was essentially normal. The Redman times; Federation "grass-clump" dwarf selection (F6) produced many tillers, but no fertile tillers when grown in a temperature regime that included 16ensp;h of 16 deg;C. Fertile tillers were produced in all other temperature regimes, but extensive tillering was observed if the temperature treatment included 8ensp;h of 16 deg;C. Completely normal growth was observed at temperatures above 26 deg;C.The six F1"grass-clump" hybrids elongated and produced seed when grown at 30 deg;C.All "grass-clump" dwarf hybrids and dwarf selections investigated to date differ from normal varieties of wheat in that they are sterile dwarfs when grown at low temperature but grow essentially "normal" above a threshold temperature. Depending on the particular hybrid or selection the required temperature may be 21, 26, or 30 deg;C. In general, if the precise temperature requirements are not known, it appears probable that elongation and seed production by "grass-clump" dwarf can be induced by growing them under continuous light at 26 to 30 deg;C.