Variability in proximate quality traits of 10 accessions of African walnut (Plukenetia conophorum) from southwestern Nigeria

Abstract

Fresh capsules of African walnut similar in maturity age were collected from nine locations in Ekiti State and one from Kogi State. Fresh and boiled nuts were assayed for proximate composition following AOAC standards. Data obtained were subjected to analysis of variance and genotype x traits biplot analysis. Results showed that most proximate traits differed significantly (p < 0.05) across accessions. Main effect of accession showed that ash content (6.48 %) was highest in Aba-Oyo, which was statistically similar to Ara (6.46 %) accession. Ogotun accession was outstanding in crude protein (18.40 %) whereas Alafe accession was the best with respect to crude fat (41.09 %) and dry matter content (91.25 %). Highest crude fiber (11.67 %) was obtained in accession from Oranre and was statistically similar to Aramoko (11.63 %). Moisture content (9.58 %) was highest in accession from Aramoko but lowest (8.76 %) in Alafe accession. Accession from Ara possessed the highest nitrogen free extract (15.62 %). Main effect of processing showed that ash (6.40 %), crude fat (40.77 %), crude fiber (11.76 %), moisture content (9.07 %) and nitrogen free extract (14.97 %.) were higher in fresh nuts. Crude protein (19.20 %) and dry matter content (90.94 %) increased in boiled nuts. The biplot shows that crude protein was higher in boiled nuts in most of the accessions but moisture, dry matter content and fiber were generally higher in fresh nuts. Study showed that genetic variability existed among the accessions, which could provide basis for genetic improvement.