Vegetative propagation of African walnut (Plukenetia conophora) using pre-treated stem cuttings of varied physiological ages

Abstract

The effect of physiological age of stem cuttings and pre-planting treatment on adventitious root and shoot growth of stem cuttings of African walnut (Plukenetia conophora) were investigated at Nsukka, Nigeria in 2012. Nodal cuttings of semi-hardwood and softwood categories were dipped in water and coconut water for 30 minutes before planting. Cuttings used as control treatment were neither dipped in water nor coconut water. Factorial combinations of age of stem cutting and pre-planting treatment were arranged in completely randomized design (CRD) and replicated three times. Results of analysis of variance (ANOVA) indicated a non-significant main effect of age of stem cutting and pre-planting treatment on number of days to breaking of dormancy and shoot formation. Physiological age of cuttings significantly (p < 0.05) influenced number of shoots formed, length of vine and number of leaves in favour of the semi-hardwood cuttings. Significant interaction between age of cuttings and pre-planting treatment was observed on percentage of cuttings with shoot and number of shoots per cutting. While semi-hardwood cuttings gave higher number of shoot when dipped in water, softwood cuttings (at 2- 4WAP) did better when dipped in coconut water. Available data suggest that softwood cuttings of this species are more amenable to clonal propagation. However, if semi-hardwood cuttings must be used, then dipping in water becomes a necessity. Evidences from this study affirm the practicability of clonal propagation of P. conophora via stem cuttings.

Key words: African walnut, Pre-treatment, Vegetative propagation, Stem cuttings.