Growth responses of Marquillo times; Kenya Farmer wheat dwarf 1 and 2 to gibberellic acid, kinetin, and indolebutyric acid under controlled environmental conditions

摘要

A "grass-clump" dwarf wheat, Marquillo times; Kenya Farmer 2 was grown in growth cabinets under continuous light or a 16-h photoperiod and a temperature regime of 8ensp;h 21 deg;C and 16ensp;h 16 deg;C. Plants were treated singly or with combinations of gibberellic acid (GA), indolebutyric acid, and kinetin. Indolebutyric acid and kinetin had no effect on plant height or development and did not alter the response to gibberellic acid. Gibberellic acid treatment increased culm height and induced plants to flower earlier but suppressed final yields of shoot and seed. Continuous light decreased plant height, time to ear emergence, and tiller number but did not alter shoot or seed yields.Marquillo times; Kenya Farmer wheat dwarf 2 and Marquillo times; Kenya Farmer wheat dwarf 1 were grown in growth cabinets under continuous illumination at various combinations of soil and air temperature. Plants were treated with gibberellic acid at 2-day intervals. The primary low temperature lesion in the grass dwarfs appears to affect early vegetative growth and leads to a premature cessation of the development of each tiller. If growth ceases before sufficient leaves are produced, the plants cannot become reproductive. Continuous light and GA treatment promotes reproductive development because both promote floral initiation at an earlier vegetative stage, i.e. a lower leaf number. Thus, if the temperature conditions allow the plants to grow to this vegetative stage before growth ceases, they will become reproductive if treated with GA but will not become reproductive if untreated. At 26 deg;C, where control plants develop normally, GA treatment results in earlier heading but much reduced seed yields.