The longevity of annual wild Helianthus seeds in short- to medium-term storage conditions

Abstract

Wild species are important in sunflower breeding as a source of genetic variability, as the re quired characters are not always available in the cultivated sunflower gene pool. The use of wild species is complex due to interspecific cross incompatibility, while regeneration of accessions can be difficult because of low self-fertility. Viability of seeds over extended periods is thus important as it directly influences the frequency of regenerations and seed availability in active collections. Viability of 7 annual wild sunflower species stored up to 14 years at 4 ± 2 ºC and 55 ± 5% relative humidity is reported. Initially the germination slightly increased, which was most visible in H. niveus, and after 3 to 5 years started to decrease, but the curve parameters were species characteristic. After 8 years, the evaluated species had on average 20% lower germination. H. argophyllus, H. petiolaris and H. praecox retained highest germination after 8 years: 70, 65 and 60% respectively. The largest decrease was found for H. neglectus and H. annuus where germination decreased to 50%.