Germination Biology of Picralima nitida(Stapf) under Pretreatments

Abstract

Viable seed sometimes fails to germinate under favourable conditions. The study assessed the germination of Picralima nitida (Stapf) seeds following pretreatments. Fruits were collected from Benin, Southern Nigeria (lat. 60 231N and long. 50 131E). The seeds were extracted manually and processed for sowing. Seeds were pretreated using ten pretreatment methods: control; soaking in water at 900C and allowing to cool overnight; soaking in water at room temperature; seeds which coats were manually removed; soaking in concentrated sulphuric acid (H2SO4) for 1min; 2mins; and 5mins; and soaking in primarily recycled H2SO4 for 2mins, 5mins and 10mins. One hundred seeds were assigned to each treatment and replicated in two locations of Akungba (lat. 70 281N and long. 50461E) and Ibadan (lat. 70 241N and long. 30 491E). Seeds were sown in germination trays containing washed-sterilized river sand in the screen house. Germination counts were taken daily. P. nitida exhibited “durian-epigeal” germination, seeds which coats were manually removed were the first batch to germinate 17 and 22 days after sowing (DAS) in Ibadan and Akungba respectively. The highest germination percentage of 100 in Ibadan and 84 in Akungba were obtained among this batch. Seeds soaked in water at room temperature gave 86% germination in Akungba and 63% in Ibadan. Seeds soaked in water at 900C, and primarily recycled H2SO4 acid for 10mins did not germinate for 106days. Analysis of variance revealed significant differences at P≤0.05 in treatment and location effects. Mean germination percentage of seeds which coats were removed was significantly different from other treatments. The inherent dormancy in P. nitida seed can be treated by manually removing the seed coat before sowing.