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Rice varietal diversity was assessed in Guinea on the basis of surveys of 1679 farms located in 79 villages of the four natural regions of the country. The descriptors used were the number of known varieties, the number of cultivated varieties and Shannon's diversity and evenness index.On the basis of their use rates, varieties were classified as major or minor types at the village scale and as regionally and/or nationally eminent varieties at these scales. Varietal diversity was high, especially in forest Guinea and lower Guinea. Diversity pattern was typical of the subsistence farming system. The high share of local variety reflected the predominance of low management and low input cropping systems. The presence of improved varieties confirms farmers' openness to innovation and to the government policy of promoting improved varieties. Regional diversity reflected the agro-ecological diversity and specificities of each region, the history and the extent of rice-growing systems, and the importance of rice in the local diet. Recent dissemination of NERICA varieties has not caused any reduction of pre-existing varieties. The short-duration NERICA are mainly used as a complement to the long-duration traditional varieties and thus enhance varietal diversity. Risks of diversity erosion seem limited in the current setting of farming system and diversity structure. However, at the village level, the diversity pattern is fragile as the proportion of farmers who used each variety of the village is low and heterogeneous. A continuous monitoring of the dynamics of rice varietal diversity in Guinea is needed.

Insufficient knowledge of the germination ecology of local species is one of the main constraints to restoration of degraded rural lands. We tested seeds from fourteen Sudanian savanna species targeted for restoration for their response to two different pretreatments (conventional and prolonged acid pretreatments) and two different storage conditions (ambient room conditions and refrigerator at 4°C). For 6 of the studied species, longer soaking in sulphuric acid significantly improved germination rates and also reduced the germination time of some species. Storage condition, in general did not affect germination rates except for two species where cool storage depressed germination. The practical implication is that, for the species tested, when mature seeds are collected for plantation in the upcoming rainy season, there is no need to invest in infrastructure and energy for storing in cold conditions. The study also revealed that in general when seeds are stored in ambient conditions from the time of collection up to seeding time, although germination rate does not increase, germination time is shortened and this could be of great interest in synchronizing germination in real field conditions. Keywords Tropical dry forest Á Seed storage conditions Á Pretreatments Á Regeneration Á West Africa Acid 30 mn ? 24 h water Adansonia digitata L. Ad.dig Bombacaceae PD Acid 60 mn ? 24 h water Acid 120 mn ? 24 h water Albizia chevalieri Harms Al.che Leguminosae PD Acid 5 mn ? 24 h water Acid 60 mn ? 24 h water Anogeissus leiocarpa Guill. & Perr. An.lei Combretaceae ND 24 h in water Acid 5 mn ? 24 h water Balanites aegyptiaca (L.) Del. Ba.aeg Zygophyllaceae ND 72 h in water Acid 120 mn ? 24 h water Cassia sieberiana DC. Ca.sie Leguminosae PD Acid 5 mn ? 24 h water Acid 60 mn ? 24 h water Combretum glutinosum Perr. ex DC Co.glu Combretaceae ND 24 h in water Acid 10 mn ? 24 h water Combretum micranthum G. Don Co.mic Combretaceae ND 24 h in water Acid 10 mn ? 24 h water Detarium microcarpum Guill. & Perr. De.mic Leguminosae ND Acid 30 mn ? 24 h water Acid 120 mn ? 24 h water Diospyros mespiliformis Hochst. ex A. DC. Di.mes Ebenaceae PD Acid 10 mn ? 24 h water Acid 120 mn ? 24 h water Piliostigma reticulatum (DC.) Hochst. Pi.ret Leguminosae PD Acid 30 mn ? 24 h water Acid 120 mn ? 24 h water Piliostigma thonningii (Schumach.) Milne-Redh. Pi.tho Leguminosae PD Acid 10 mn* ? 24 h water Acid 120 mn ? 24 h water Tamarindus indica L. Ta.ind Leguminosae PD Acid 10 mn ? 24 h water Acid 120 mn ? 24 h water Terminalia avicennioides Guill. & Perr. Te.avi Combretaceae PD Acid 30 mn ? 24 h water Acid 180 mn ? 24 h water * Conventional treatment is 5 mn ? 24 h soaking in water. This was tested in previous paper (Dayamba et al. 2014, JTFS in press) and showed poor germination. This is why we increased the soaking time. Dormancy status: PD is physically dormant; ND is non dormant (

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