Daymond, A.Tricker, P.Hadley, P.2014-10-222014-10-222011Biologia Plantarum: journal for experimental botany, 2011; 55(1):99-1040006-31341573-8264http://hdl.handle.net/2440/86521Variation in photosynthetic parameters was observed between eight contrasting cacao (Theobroma cacao) genotypes. Net photosynthetic rate (PN) ranged from 3.4 to 5.7 μmol(CO2) m−2 s−1 for the genotypes IMC 47 and SCA 6, respectively. Furthermore, genotypic differences were detected in quantum efficiency ranging from 0.020 to 0.043 μmol(CO2) μmol−1(photon) for UF 676 and AMAZ 15/15, respectively. Differences in PN were correlated with both stomatal conductance (gs) and leaf nitrogen per unit area. Some variation in water use efficiency was observed between genotypes, both intrinsic (PN/gs) and instantaneous (PN/transpiration rate). Both measures of water use efficiency were a negative function of specific leaf area. Evidence was found for a trade-off mechanism between cacao genotypes in photosynthesis and leaf structure. High photosynthetic rate, expressed on a mass basis was associated with smaller leaves. Furthermore, thinner leaves were compensated for by a higher nitrogen content per unit mass.en© Springer, Part of Springer Science+Business MediaLight response curves, quantum efficiency, specific leaf areaJournal article003001024510.1007/s10535-011-0013-y0002866697000132-s2.0-7925155571587506Tricker, P. [0000-0002-1626-3556]