Cultivars Of Fragaria Research Articles

Differences in the structure of pollen in the ‘Senga Sengana’ and ‘Selva’ cultivars of Fragaria × ananasa

The strawberry belongs to one of the youngest species of arable crops. The study aimed to analyze pollen's structure in the ‘Senga Sengana’ and ‘Selva’ cultivars of Fragaria × ananassa. The strawberry is a dicotyledonous plant from the Rosaceae family. The article presents research carried out on Fragaria × ananassa cv. ‘Senga Sengana’ and ‘Selva’ collected during flowering. Pollen mor-phology was examined using a scanning electron microscope and a traditional optical microscope. The results showed that fresh pollen outnumbered dead pollen, confirming that the ‘Senga Sengana’ culti-var produces larger amounts of fertile pollen. Mature ‘Senga Sengana’ pollen grains are characterized by a specific sculpture of the exine walls. The analysis of Selva pollen grains revealed substantial changes in the structure of the sporoderm during its maturation. It becomes thicker and, as the size of the pollen grain increases, the exine layer becomes more elaborate.

Simplified AFLP procedure as a tool for identification of strawberry cultivars and advanced breeding lines

DNA polymorphisms among 6 cultivars of Fragaria × ananassa (Duch.) and 13salinity tolerant clones were evaluated using simplified – PstI based Amplified Fragment Length Polymorphism procedure(PstIAFLP). Out of 129 amplification products obtained with 10 selective primers, 116 markers were polymorphic and could be used to distinguish all analyzed materials. Coordinate and cluster analyses revealed 2 main groups of clones and divided strawberry cultivars (CUL) and tested F1 hybrids of ‘Sweet Heart’(HYB). Mean genetic similarities in groups of cultivars and selected breeding lines (SEL) were significantly higher (0.722 and0.706, respectively, p < 0.05) than in group of SH hybrids (0.485). Results suggest that PstIAFLP method is sufficient for effective identification and useful for assessing the level of genetic diversity in strawberry cultivars and breeding lines. The presented method can bean alternative multilocus marker system to widespread RAPD method.

Bacterial Angular Leafspot Disease of Strawberry: Search for Resistance

Bacterial angular leafspot disease (BALD) of strawberry, caused by Xanthomonas fragariae, a slow-growing and often difficult pathogen to isolate from infected plants, is most commonly manifested as small discrete, angular, translucent lesions on leaves and sepals. As the bacteria infect systemically, plants may wilt and die. BALD has become increasingly important in North America and other strawberry-growing areas of the world. The systemic nature of the pathogen also is cause for concern with international shipment of strawberry plants, especially because there is no practical method for determining the presence of the bacteria in symptomless, infected plants, nor is there a practical method of chemical control. All cultivars of Fragaria × ananassa (8×) are susceptible to BALD, although a range of susceptibility is often apparent in plantings. Resistant genotypes have been reported among clones of F. virginiana (8×), F. moschata (6×), and F. vesca (2×). A program has been initiated to evaluate native octoploid and diploid strawberry germplasm for resistance to BALD.

Pollen Ultrastructure of Strawberry and other Small-fruit Crops1

Abstract Scanning electron microscopy studies were made on pollen samples from several small fruit crops: 3 selections of blueberry (Vaccinium), 4 Vitis spp. (V. vinifera L., V. cinerea Engelm., V. rupestris Scheele, and V. amurensis Rupr.), 2 cultivars of raspberry (Rubus), 5 cultivars of blackberry (Rubus), and several species and ploidy levels of strawberry (Fragaria) including 54 cultivars of F. × ananassa Duch., as well as pollen of Duchesnea and Potentilla. Pollen size and exine characteristics were similar for 4 grape species examined. Polyploid blueberry selections were separable from the diploid selection by pollen grain size. Raspberry and blackberry pollen differed in size, exine ridging or reticulation, and presence of borderless or collared pores. Strawberry pollen is characterized by exine ridging and absence of pores. Cultivars of Fragaria × ananassa could be categorized into 4 groups according to exine ridge patterns. Cultivars exhibited broad longitudinal ridges or were characterized by less prominant to indistinct ridges. One cultivar was unique in that anastomosing ridges were present between adjacent ridges. Pollen grains of diploid F. vesca L., F. vesca fma. semperflorens Duch., and F. nubicola Lindl, ex Lacaita; a tetraploid clone of F. vesca; the hexaploid F. moschata Duch.; and octoploid F. × ananassa, F. chiloensis (L.) Duch., and F. virginiana Duch. are broadly elliptical, tricolporate and moderately to prominently ridged. Size of pollen and prominance of exine ridges appeared to correspond with ploidy level. Pollen of F. nipponica Mak. differed in that grains are subprolate to sphaeroidal and exine is ornamented with minute, rounded to subconical verrucae arranged in rows. Pollen of the related genera Duchesnea and Potentilla were very similar morphologically to those of octoploid Fragaria spp., except that pollen of D. indica (Andr.) Focke are larger and the exine of P. recta L. exhibits an extremely minute pore structure.