Brazil nut (Bertholletia excelsa) seed characteristics, preimbibition and germination

Although the seeds of Brazil nut are very popular on the international nut market, little is known about the basic seed characteristics and germinatio n of this important tropical species. We compared seed mass, length, width and moisture content of ten maternal families of Brazil nut collected in Ac re, Brazil. Employing a randomized complete block design, we also examined the effects of two preimbibition treatments on Brazil nut seed moisture con tent and germination, while controlling for family variation and strictly l imiting the time period between seed shedding, collection, and sowing. All seed characteristics varied between families. There was no correlation betw een germination success and seed size, or any other seed characteristics. M oisture content of whole seeds was high (25%), and although preimbibition r esulted in significantly higher moisture contents for whole seed and embryo , it did not affect germination success. After complete seed coat removal, embryos began germinating 60 days after sowing, and germination continued f or 274 days, concluding with a mean percentage germination of 55%, and 45% seed deterioration, with significant differences between families for all g ermination pleasures. We speculate that this delayed and prolonged germinat ion may be due to endogenous seed dormancy, although the mechanism for this dormancy remains unknown.