Survival, Growth and iOrygmophora mediofoveata/iShoot Borer Attack of iNauclea diderrichii/iProgenies Established in Three Ecological Zones in Ghana

摘要

Nauclea diderrichii is a tropical African hardwood species and a suitable candidate for plantation development. However, attack by the Orygmophora mediofoveata, Hamps shoot borer threatens establishment of the species in plantations. A genotype * environment assessment of 15 N. diderrichii progenies from Ghana and Togo was conducted in the Wet Evergreen, Moist Semi-deciduous and Dry Semi-deciduous forest zones. Progeny performance (Attack intensity, survival and growth) varied significantly between sites, and marginally within sites after 2.7 years. Overall, incidence of shoot borer attack was lower at the wet zone than at the moist or dry zones. Percent survival was higher at the wet (79.5%) than at the moist (50.8%) or dry (55.0%) forest zones. Mean height across the 15 progenies was 5.40 m, 4.30 m, and 2.73 m at the wet, dry and moist forests, respectively. Similarly, mean diameter was 5.31 cm, 4.58 cm, and 2.83 cm at the wet, dry and moist zones, respectively. The relatively low growth rate recorded at the moist zone was attributed to the paucity of soil conditions at the experimental site. Three wet forest zone progenies (BS9, BS3 and BS2) and two moist forest zone progenies (BE2 and GA1) performed better than average and have been recommended for planting.