Intra- and inter- correlative responses among fruits physical traits, seedling growth parameters and fruit and nut proximate qualities of the Nigerian shea nut tree (Vitellaria paradoxa c. f. Haertn)
Seedling growth of Vitellaria paradoxa C. F. Gaertn (shea nut tree) is extremely slow. Identification of any nut trait that shows positive and significant relationship with vigorous seedling growth could therefore, be an important selection index. Besides, fruit preferences among indigenous peoples are associated with high pulp proximate quality while highly valued nut has strong relationship with fat content. Thus, intra- and inter- correlative responses among fruits physical traits, seedling growth parameters and fruit and nut proximate qualities of V. paradoxa were studied. Agronomically important seedling characters of nine provenances across Nigeria’s savanna zone were also examined with principal components analysis (PCA). Results indicated that the first three PCA axes retained explained 96.3% of total variability among seedling provenances, revealing that leaf area, seedling girth, plant height and number of leaves are more promising traits for shea seedling classification in Nigeria. Multiple correlation analysis showed that nut length had high and significant linkage with number of leaves, leaf width, leaf area and seedling girth. Nut width also correlated positively with leaf length, leaf area and seedling girth (P<0.05). Percent pulp weight had high positive significant correlation with carbohydrate and energy, but was negatively correlated with fibre. Similarly, nut diameter had positive significant relationship with fat but a negative one with carbohydrate. Correlations between percent testa weight and fat were positive. The correlative responses showed that choice of long nuts for planting could lead to vigorous seedling growth. Similarly, shea fruits with high percent pulp content could have high carbohydrate and energy contents while nuts with broader diameters may be selected for high fat content.
Keywords: Shea nut tree, Correlations, PCA, , Proximate traits, Seedling traits, Vitellaria paradoxa