RibesBloom Phenology: Sections Botrycarpumand Ribes

Abstract

The USDA Agricultural Research Service RibesL. genebank at the National Clonal Germplasm Repository (NCGR) in Corvallis, Oregon, was surveyed to determine timing of first bloom. Accessions of 106 black and 53 red currant genotypes were observed weekly during the springs of 1999, 2001, 2003, 2007, and 2008. Calendar dates were recorded for first, full, and last bloom. The dates were converted to growing degree-day (GDD) values using a heat accumulation model set to begin on 1 January at a base temperature of 5° C. Mean first bloom for red currants (section Ribes) occurred at 247 GDD, and for black currants (section Botrycarpum) at 256 GDD. Significant interaction was observed between botanical section and year, although genotypes within a section flowered in the same relative order. This report documents cultivars with blooming phenologies suited for a range of production goals and environments. Black currants, such as R. nigrumL. ‘StorKlas’ and ‘Ben Tirran,’ and red currants, R. × koehnianumJancz. ‘Mulka’ and R. rubrumL. ‘Moore’s Ruby,’ bloom in late spring and avoid early season frosts. These cultivars can be grown in locations with long, cool springs. Early-flowering cultivars, such as R. nigrum‘Risager’ and R. rubrum‘Wilder,’ may be suited for environments where heat accumulates rapidly at the onset of summer. Genotypes from both sections show potential for growers to incorporate cultivars which flower in succession from early to late spring.