Intraspecific responses of six cultivars of wheat (Triticum aestivum L.) to supplemental ultraviolet-B radiation under field conditions

The solar ultraviolet-B (UV-B) background level is often high and posing an environmental challenge in most of the tropical region of the world, including India. This prompted the present study to investigate the effects of supplemental UV-B (sUV-B) radiation (ambient + 7.2 kJ m(-2) day(-1)) on various growth, physiological and biochemical characteristics of six locally grown cultivars of wheat (Triticum aestivum L.). Plants being sessile protect themselves from the harmful UV-B radiation by synthesizing flavonoids to screen UV-B and also by inducing antioxidant defence system. sUV-B radiation negatively affected the growth of wheat seedlings but the response varied amongst the cultivars. Leaf injury was maximum in cv. PBW154 and minimum in HD2824. Values of sensitivity index also revealed that HD2824 was least sensitive to sUV-B, while PBW154 was most sensitive. All the assessed biochemical parameters corresponded well with the sensitivity index of different cultivars of wheat.