Interspecific variation in seed storage behaviour within two genera - Coffea and Citrus
1995
Hong, T.D. | Ellis, R.H. (University of Reading, Reading (United Kingdom). Department of Agriculture)
Classification of the variation in seed storage behaviour among species, especially within a genus, is required before alternative methods of ex situ conservation can be evaluated for efficacy. Seeds of robusta coffee and liberica coffee were tested for germination following desiccation and subsequent storage for up to one year at three temperatures (-20 deg C, 0 deg C, 15 deg C) with 5 to 13 % (robusta) or 5 to 14 % (liberica) moisture content. Robusta coffee seeds extracted from ripe or almost ripe fruits were less sensitive to loss in viability from desiccation than those from immature fruits. Even with seeds from red fruits, however, in which desiccation to 11.3 % moisture content reduced viability by 22 % and further desiccation to 7.0 % killed all but 2 % of the seeds, survival in the best hermetic storage environment of 15 deg C with 11.3 % moisture content was poor with only 4 % viability after 12 months. Seeds of liberica coffee were very much more sensitive to desiccation, with only 6 % surviving desiccation to 13.5 % moisture content, and no seeds surviving as few as six months' storage in any of the 15 environments tested. We conclude that liberica coffee shows recalcitrant seed storage behaviour, but that robusta coffee shows an intermediate category of seed storage behaviour similar to that shown by arabica coffee. Evidence is collated which suggests similar interspecific variation in seed storage behaviour within the genus, and that the intermediate category is discrete rather than a continuum between orthodox and recalcitrant
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