ISSN: 0041-3216 (Online), 0041-3216 (Print)
Volume 65 Number 3
Comparative drought tolerance of cacao accessions
The water relation components, stomatal behaviour and biochemical parameters were determined in 14 cacao accessions. Based on the parametric relationships with drought tolerance, the rank sums of these accessions lead to a selection of five of them, NC 23, NC 29, NC 31, NC 39 and NC 42. These drought tolerant accessions had effective stomatal regulation resulting in decreased transpiration under water stress, which seems to be an important strategy for adaptation in cacao. Although a decrease in osmotic potential and nitrate reductase activity and an increase in soluble sugar were noticed in response to stress, there was no relationship with respect to drought tolerance. The stomatal diffusive resistance was negatively correlated with transpiration. The cacao accessions with the higher drought tolerance characteristics and higher yield potential under drought stress should be useful basal material for selective breeding.
Keywords: Cacao; Drought tolerance; Water relations; Stomatal regulation