Leaf and fruit characteristics of Shea (Vitellaria paradoxa) in Northern Ghana

Leaf and fruit parameters of Vitellaria paradoxa populations in north-south gradientof the shea belt in the transitional and Guinea Savanna zones of Ghana were comparedduring the fruiting season between April to July, 2011. Leafmorphological traits studied include laminar width, petiole and laminar lengths. Fruitparameters measured include fruit and kernel widths, lengths, weights and pulp weight.Results showed variability for most of the characters determined. The leaves in Paga hadshorter petioles as compared to those of Nyankpala and Kawampe. The Nyankpala V. paradoxa has the smallest laminar width whilst Kawampe has longest leaf laminar ascompared to the rest. Values for fruit and kernel parameters were highest for samples fromPaga, followed by Kawampe and were significantly higher than those from Nyankpala.There were significant positive relationships between fresh fruit weight and both freshkernel weight (P < 0.001; R2 = 0.6925) and dry kernel weight (P < 0.001; R2 = 0.6532) for datapooled from all the three locations, however, the slopes and intercepts varied betweenlocations (P < 0.001). The result from the study provides opportunities and prospects forselection and breeding for V. paradoxa tree improvement in Ghana

Relationships between climate at origin and seedling traits in eight Panafrican provenances of Vitellaria paradoxa C.F. Gaertn. under imposed drought stress

The morphological responses of seedlings of eight African provenances of Vitellaria paradoxa (Shea tree or Karité) to imposed draught stress were compared under nursery experimental conditions. The potted seedlings were subjected to three different watering regimes (87 days after sowing): no water stress (100% of the field capacity, C), moderate water stress (75% of C) and severe water stress (50% of C). Before the application of the stress, we observed genotypical differences in the morphological variables at the scale of leaves and of above-ground parts. The six-month water stress affected aerial growth: all provenances responded to drought by down-regulating growth (in height and in diameter), leaf number and area. Katawki provenance of Uganda performed relatively poorly, possibly of it being a nilotica subspecies, contrary to the others (paradoxa subspecies). There was a lack of correlation between climate of seeds origin, seed characteristics, seeds germination and survival rate of seedlings. The study confirmed the importance of leaf area in the vigor of the initial growth in this species. Thus, Tamale and Karaba provenances performed better than other West African provenances due to their larger leaf area, which was found to be a determining factor of relative growth in height at the seedling stage. (Résumé d'auteur