Screening cacao germplasm for drought tolerance. In: Agrotrópica v. 34 n. 1 p. 5-18, 2022.

Abstract

Thirty progenies of the Cacao Research Center’s (Cepec) cacao breeding program were submitted to water restriction and evaluated for survival, height, stomatal density, relative water content (RWC) and parameters related to the pressure-volume curve under greenhouse conditions. Drought caused an average of 120% reduction in water potential, and a decrease in RWC and survival in some progenies. A high survival capacity was observed for progenies of clones CP-309 and CP-300 characterizing resistance to severe drought under greenhouse conditions. Furthermore, these progenies showed lower losses in RWC. In the progenies evaluated it was identified mechanisms compatible with osmotic and elastic adjustment that have a role in drought tolerance and some positive correlations with plant survival in severe drought in the greenhouse, like RWC at the turgor loss point, that was considered as the main predictor of severe drought survival under controlled conditions. Given the complexity of the plant’s tolerance responses and the genetic variability of the plants in Cepec cacao germplasm, we highlight the importance of screenings like this, as a starting step for cacao breeding programs aiming drought tolerance.