Fruiting efficiency of the African walnut (Lovoa trichilioides Harms): a case study of Benin tropical rainforest and Onne swamp forest of Nigeria

Abstract

The influence of geographical location on fruiting efficiency and abortion rate of gynoecium per inflorescence were investigated between 2004 and 2006 at two locations of Nigeria (the tropical low land rain forest of Benin and Onne swamp forest) Five (5) sample trees each of L. trichilioides were randomly selected in Iguowan forest (Benin) and Onne swamp forest. Twenty (20) inflorescences were randomly selected per tree at each site. Mean fruiting efficiency per inflorescence was calculated by dividing the number of fruits-set by the total number of flowers produced and multiplied by one hundred. The mean fruiting efficiency of L. trichilioides were 9.0 ± 0.14% and 9.35 ± 0.09% in Benin and Onne respectively. Similarly, the mean abortion rate of gynoecium were 91.0 ± 0.14% and 90.65 ± 0.09% for Benin and Onne respectively. L. trichilioides has irregular fruiting pattern since it fruits once in two years without inter annual variability. Competing sink for available food resources, pollination and fertilization failures could be speculated as factors responsible for low fruiting efficiency and high abortion rate in L. trichilioides. The use of vegetative growth retardant sprays such as endothall and artificial pollination during flowering are recommended.

Keywords: Lovoa trichilioides, African walnut, fruiting efficiency, gynoecium drop, inflorescence number, geographical location