Germination study of three fabaceae species, endemic of south-western region of Madagascar
Hanitriniala Domohina Sylvia Randrianarisoa1, Nasolo Diary Nandrianina Randriamora1, Rakotomalala Yedidya Ratovonamana2,3, Ononamandimby Antsonantenainarivony3
1University of Antananarivo, Dept. of Environment, Madagascar
In the south-western region of Madagascar, the Fabaceae family is commonly used by the local population for different purposes along with their ecological importance. Its natural regeneration rate is very low because of the problems related to physiological and morphological seed dormancy and other ecological factors. To overcome these difficulties, ex situ multiplication of seedlings is essential to ensure the sustainable use of the Fabaceae species which are of socio-economic, ecological and cultural importance. Thus, a germination test was undertaken for three endemic woody Fabaceae species encountered in Tsimanampesotse National Park such as Acacia bellula, Delonix floribunda and Tetrapterocarpon geayi. The aims of this study is to identify the optimal conditions for seed germination and seedling growth. Four factors or treatments closely related to seed germination and seedling growth were tested: pre-treatments, seed size, substrates and water salinity. The results revealed that these treatments showed significant effects on germination rates for all species studied. Manual scarification led to the highest germination rate for A. bellula (60.2%), D. floribunda (58.7%) and T. geayi (87.9%). For A. bellula, the largest seeds gave the highest germination rate (70.33%). For D. floribunda and T.geayi, the highest germination rate were obtained with medium size seeds, with 67.06 and 77.4% respectively. The results showed that only A. bellula tolerates the salinity of the water at the time of germination and growth, with a germination rate of 80%, corresponding to the dose of 10 g/L NaCl. For D. floribunda and T. geayi, the germination rate at 10 g/L NaCl dose is low, with 1.40 and 57.05% respectively. D. floribunda is well adapted to all types of substrates tested, with a germination rate of about 80%. Calcareous soil was the most favourable not only for germination, but also for growth and viability of the seedlings of the two species. Because of their simplicity and low cost, these techniques are recommended for the future production of seedlings in this region, while preserving the sustainability of these species.
Keywords: Fabaceae, germination, growth, seed, Tsimanampesotse
Contact Address: Hanitriniala Domohina Sylvia Randrianarisoa, University of Antananarivo, Dept. of Environment, Antsirabe, Madagascar, e-mail: domohinasylviahanitrinialagmail.com