Cultivar trials comparing nine early maturing and 14 medium maturing peanut (Arachis hypogaea L.) lines were conducted over 3 yr at five sites in Northern Benin. Trials were conducted using presently recommended agronomic practices. Pod and biomass yields, defoliation from all causes and phenology were observed. Crop growth rate (C), partitioning (p) and reproductive duration (parameters of a simple physiological model for yield) were estimated. Both C and p contributed to yield differences among lines within a maturity group. The dwarf cultivar MH2 was in all cases lower yielding due to low C. Duration was apparently not an important determinant of yield differences between early and medium maturity trial sets since (with MH2 excluded) the extra time taken by the medium maturity lines only resulted in 50 kg/ha greater yield. Partitioning of the trial entries was high suggesting that selection should focus on traits that maximize C. Across all lines there appears considerable potential for higher yields achieved by improvements of the crop growth rate, and crop management research and breeding should focus on tactics to increase this determinant of the yield. Lines selected for resistances to foliar diseases in India had, on average, lower C than West African lines, and some Southern African lines, but they had greater stability of C across environments. Stability analysis of yield and the parameters of the yield model identified lines with superior stability of p and others with superior stability of C. It is suggested that both phenotypic and physiological yield models should be used in the identification of lines with desirable adaptive attributes.