Drought and high heat stresses modify Brassica napus L. leaf cuticular wax

Brassica napus L. is dual-purpose oilseed crop for food, feed and biofuel. Breeding for cultivars adapted to environmental stresses, especially drought and high heat stresses, is one of the strategies that has the attention of breeders. To evaluate the effects of those stresses on leaf wax accumulations, a replicated growth chamber experiment was designed to include three factors: drought (D), high heat (H) and genotypes (G). Data showed significant variations in leaf wax accumulations in response to those three factors and their combinations. For example, the accumulation of the C24 primary alcohol wax was affected by heat, drought, genotype, DxH, HxG, DxG and DxHxG, while the accumulation of the C16 fatty acid wax was affected by drought only. The results indicated that brassica leaf wax accumulation rates under those stresses are genotype dependent and suggest choosing specific parent(s) is an important factor for breeding for those stress factors. The C28 fatty acid, C29 primary alcohol and C30 alkane waxes showed abundance on brassica leaves grown under combination of drought and heat stresses, suggesting them as potential candidates for improving the stress tolerance against those intense stressors. Combination of drought and heat showed to have synergetic effects on specific brassica leaf waxes indicating the possibility to breed for both drought and heat tolerances in Brassica napus at the same time.