Flowering Tendencies in Octoploid Strawberry Species
2016
Hummer, Kim E. | Oliphant, Jim M. | Bassil, Nahla V.
The U.S. Department of Agriculture, National Clonal Germplasm Repository (NCGR), Corvallis, Oregon, maintains a national genebank for strawberry, Fragaria L. This collection includes diverse species maintained in screenhouses. The plants are exposed to an annual temperature regime that allows flowering. The objective of this project was to examine the flowering tendencies of octoploid strawberry taxa to determine if the blooms were seasonal (once per year) or successive blooming (remontant). For each of 68 clones of nine taxa, flower presence was recorded on the first day of each month from June through Oct. 2002 and in 2004. Complete flower trusses were removed after scoring. Plants flowering only in June and/or July (or earlier) were considered “seasonal”; those with later flowers were considered “successive blooming.” For both years, North American F. chiloensis ssp. lucida and ssp. pacifica flowered seasonally, significantly different than clones of ssp. chiloensis f. patagonica , half of which were successive blooming. A clone of ssp. pacifica from Hartney Bay, Alaska, was successive blooming. The flowering in two clones of South American ssp. chiloensis f. chiloensis and one of the Hawaiian ssp. sandwicensis were seasonal. Fragaria virginiana ssp. grayana clones and half of the ssp. virginiana Mill. flowered seasonally; the rest of the clones of those subspecies were successive blooming. Flowers of a clone of F. virginiana ssp. platypetala from California were seasonal while those from a second one from Eastern Oregon were successive blooming. This clonal phenotypic information is of specific use for geneticists to determine parental crosses. This study will be continued and broadened to include diverse global species.
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