Incidence and control of seedborne fungal infections associated with post-germination mortality in seedlings of Melia volkensii Gurke.

Abstract

A laboratory study was carried out at the School of Biological Sciences, Chiromo Campus, University of Nairobi, for identification of seed-borne fungi that emerge during germination of M. volkensii seeds. The study sought to determine the incidence, pathological symptoms and effects of the fungi on post-germination survival of seedlings. Mature seeds collected from wild trees in three agro-climatic zones in semi arid eastern Kenya were scarified by nipping and slitting of the testa and divided into two groups. The treatment group received a single pulse pre-treatment consisting of a 30-minute soak in 1% (m/v) Bavistin, while the control group was soaked in tap water. Aspergillus flavus and Rhizopus stolonifer infections emerged in the control group. A Mann-Whitney U test showed the control group as having significantly higher infections with both fungi (range of p values=0.003 to 0.010) during and after germination than the fungicide-treated group. Post-germination seedling survival was also significantly enhanced by 31.66% in the treated group relative to the control (range of p values=0.004 to 0.010). A single pre-treatment with the systemic fungicide Bavistin may be recommended for reduction of seedling mortality in M. volkensii during and after germination.