Variation in epicuticular wax content in wheat.

Cultivars of common wheat (Triticum aestivum L.) and durum wheat (T. turgidum L. var. durum) were evaluated for epicuticular wax content and its relationship with spectral reflectance. Epicuticular wax is associated with drought tolerance. Highly significant differences (1.51 to 2.80 mg/dm2) were found in the amount of epicuticular wax (EW) among the cultivars. Water stress significantly enhanced the level of EW. EW content under stress and control conditions were positively correlated (r=0.85, p<0.01) suggesting that selection for this trait could be practised in either environment. Surface reflectance was reduced when the waxy layer from the leaf was removed with chloroform. The reduction for the abaxial surface was twice that for the adaxial surface indicating that the abaxial surface was more waxy than the adaxial one. The mean reduction (both surfaces) termed ‘δ’ was positively correlated with the amount of EW (r=0.59, p<0.01).