Pollen Morphology of some Cultivated Varieties of Strawberry

Abstract

Pollen grains of twelve cultivated varieties of strawberries grown in Egypt were morphologically studied using both light microscopy and SEM observations. These varieties include eleven cultivars of Fragaria x ananassa (c.v: Capitola, Douglas, Chandler, Selva, Fern, Seascape, Dorite, Pajaro, Parker, Sequioa, Oso Grande) and one cultivar of Fragaria vesca. Pollen grains of Fragaria are spheroidal, subprolate ellipsoidal to triangular in outline. Tricolporate with long colpae tapering to pointed ends. Exine sculpture is always striate. These studied cultivers are discrepant mainly in pollen size, shape and striation pattern, which may be useful for identification of the cultivars and can be merged into seven morphological pollen groups. The differences in pollen morphology among Fragaria species and cutivars apparently corresponds with ploidy levels of the species. The quantitative measurements of pollen grains diameter using image analysis showed that there is a great variation in and between different strawberry cultivars studied. Generally, pollen grains of Fragaria are spheroidal, ellipsoidal to triangular in outline when dry, but readily take up moisture and expand, becoming oblately flattened and angular in outline.