Response of barley and pea crops to supplementary UV-B radiation

Four cultivars of winter barley (Hordeum vulgare L.) and two cultivars of c ombining pea (Pisum sativum L.) were grown in the field in the UK (52 degre es N) and irradiated under banks of UV-B lamps in 1994/95 (barley) and 1996 (pea). Supplementary UV-B radiation was applied to treated plots as a prop ortional addition to the UV-B dose received under a control plot. Treated p lants received a UVB enhancement simulating the consequence of a 15% reduct ion in the amount of stratospheric ozone. No significant effect on yield an d few significant effects on growth, pigment composition or chlorophyll flu orescence variables were detected. However, interplot variability was such that yield differences of < 8.5% (pea) and < 21.6% (barley) had less than a 95% probability of being detected as significant at the 5% level. The resu lts indicate that yields of pea, and probably barley, would not be markedly affected by the increase in UV-B associated with a 15% reduction in strato spheric ozone. However, given uncertainties, such as the possible interacti ons between the effects of W-B and those of other environmental factors, th e possibility of significant crop responses to stratospheric ozone depletio n cannot be excluded.