EFFECT OF TEMPERATURE ON THE GROWTH OF WHEAT: I. MARQUILLO, KENYA FARMER, AND TWO DWARF PROGENY

Abstract

Wheat varieties, Marquillo, Kenya Farmer, wheat dwarf 1 (Marquillo × Kenya Farmer), and wheat dwarf 2 (Marquillo × Kenya Farmer) were grown in growth cabinets under continuous light at an intensity of 1200 ft-c and temperatures of 16, 21, 26, and 31 °C combined in all possible combinations for 16-h and 8-h periods in a 24-h cycle.Wheat dwarf 1 elongated and produced seed only when soil and air temperature was kept at 26 °C or higher. If the plants were exposed to 21 °C or less for 8 h or longer, only a "grass-clump" habit of growth was observed. At still lower temperatures only a small primary tiller was produced. Wheat dwarf 1 plants, initially grown at 21 °C for 30 days or longer, would not grow and head when transferred to 31 °C. Plants initially grown at 31 °C did not continue to grow when transferred to 21 °C. Wheat dwarf 2 required a temperature of 21 °C or higher to induce elongation. At lower temperatures plants were dwarfed but fertile tillers were produced. Only at 16 °C was a "grass-clump" habit of growth observed.In contrast to the dwarfs, the tallest plants of Marquillo and Kenya Farmer were produced at the lowest temperatures and maximum yield of shoot and seed was obtained under a regime that would be equivalent to a continuous temperature of 17–20 °C.