Effects of gamma irradiation on growth and yield of agricultural crops-I. Spring sown wheat

Abstract

The effects of acute doses of γ-irradiation ranging from 250 to 2000 rad delivered to wheat at various stages of growth were investigated. Before tiller initiation was complete, doses of 2000 rad caused premature death, while 750-1250 rad led to the number of tillers and ears being increased by factors of up to three. Some enhancement of tillering was also caused by 500 rad delivered at the 2-leaf stage. These effects were shown to depend on the doses received by the apical meristems; increased tillering was always associated with some retardation in the development of the main axis. In contrast when plants were irradiated after tillering was complete neither the number of tillers nor the number of ears was affected by doses up to 2000 rad. The weight of seed per plant was unaffected by exposure to 500 rad. The effects of 1000 rad were variable, but on average yield was reduced to about 60 per cent of that in the control; no consistent relationship was found between the effects of this dose and the age when plants were irradiated. In contrast the effects of 2000 rad varied greatly during the growing season; exposure, before tillering was complete, inhibited all ear development, at the time of ear emergence yield was reduced to less than a quarter of that of the controls; whereas when irradiation was deferred to the time of anthesis or later yield was much less affected. All treatments which reduced the yield of seed per plant also caused the weight per seed to be smaller. © 1969 Pergamon Press Limited.