use (Walker and Miller, 1986; Paje et al., 1988). Higher levels of leaf epicuticular wax have been shown to be The epicuticular wax load (EWL) on leaves reduces surface transpicorrelated with seedling drought tolerance in Eragrostis ration and thus improves crop water use efficiency. The objectives of this study were to evaluate peanut (Arachis hypogaea L.) genotypes lahmanniana Nees (Wright and Dobrenz, 1973), with for their ELW and also to determine the influence of water deficit relative drought tolerance in oat (Avena sativa L.) cultistress on EWL. Peanut genotypes were grown in fields in two dry sea- vars (Bengston et al., 1978), and with greater water use sons (2000 and 2001) and one rainy (2000) season. Withholding irrigaefficiency in wheat (Triticum aestivum L.) (Johnson et tion water resulted in a significant increase in water saturation deficit al., 1983). Recently, it has been shown that in cocoa in the stressed crop. At 45 d after sowing (DAS), significant genotypic (Theobroma cacoa L.), the leaf epicuticular wax content differences were observed in EWL of 12 genotypes grown in the rainy increases with increased in soil moisture deficit (Anseason (2000). The values of EWL ranged from 0.91 mg dm Ϫ2 in Chico twi, 1999). to 1.74 mg dm Ϫ2 in PBS 11049, with a mean of 1.27 mg dm Ϫ2 . AmongCompared with several other crops, peanut has some six genotypes, which were also sampled subsequently, the mean values drought tolerance. Specific leaf area has been shown to were 1.10, 1.58, 2.05 mg dm Ϫ2 at 45, 75, and 95 DAS, respectively. In both dry seasons, significant genotypic differences were found in the be inversely related to drought tolerance potential of EWL. In the dry season of 2001, the effect of various moisture deficit peanut genotypes (Nageswara Rao and Wright, 1994). treatments and their interactions with the genotypes were highly sig-However, a comprehensive understanding of the contrinificant. The values ranged from 0.653 to 2.878 mg dm Ϫ2 . On an averbutions of various factors to imparting drought tolerage, the highest EWL was found in PBS 11049 (2.24 mg dm Ϫ2 ). Even ance in peanut is lacking. There are reports that indicate under irrigated conditions, in summer 2001, the EWL increased with accumulation of sucrose, proline, and amino acids in increased age of the crop. However, there was a greater increasethe leaves of peanut plant as a consequence of water in the treatments that were subjected to moisture deficit stress. It was deficit stress (Misra et al., 1991;Yadav et al., 1993).
concluded that genotypic differences exist in EWL of peanut andEarlier work on peanut did not indicate any accumulaalso that EWL increases with increased crop age. This increase is tion of wax on leaves either in response to drought or more pronounced in plants that are subjected to protracted moisture deficit stress.
