Genotypic Variation in Epidermal Conductance and its Associated Traits among Oryza sativa and O. glaberrima Cultivars and their Interspecific Progenies

Epidermal conductance (g(min)) is a measurement of water loss through the cuticle and stomata when stomatal conductance is minimal. Two pot experiments were conducted to evaluate genotypic variation in g(min) for 10 to 12 rice cultivars (Oryza spp.) grown under flooded conditions. Epidermal conductance was estimated by measuring loss of water from the excised topmost fully-expanded leaves. Considerable genotypic variation in g(min) was found. Two O. glaberrima cultivars had lower g(min), whereas the O. sativa lowland cultivars tended to have higher g(min). Excluding data for O. glaberrima, higher g(min) was associated with higher stomatal density x stomatal length, suggesting that residual stomatal transpiration contributes to genotypic variation in g(min).