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Abstract

Grape breeding was initiated at the Horticultural Research Institute of Ontario in 1913 (3). The objectives of the breeding program were to provide wine and table grapes adapted to Ontario growing conditions. ‘Vanessa’ (Fig. 1) was released by the Horticultural Research Institute of Ontario to fill the need for seedless table grapes hardy enough to withstand winter conditions in southern Ontario. This is the seventh cultivar released from this program.

Open Access
Authors: and

Abstract

Grape breeding was initiated at the Horticultural Research Institute of Ontario in 1913 (3). The objectives of the program were to provide wine and table grapes adapted to southern Ontario climatic conditions. ‘Vivant’ (Fig. 1) was released by the Horticultural Research Institute of Ontario to help fill the need for hybrid grape cultivars with vinifera-like character for the active white wine market. This is the 8th cultivar to be released from this program.

Open Access

An assessment was made to determine the suitability of RAPD analysis for identification of the Australian wildflower Ozothamnus diosmifolius (Vent.) DC [syn. Helichrysum diosmifolium (Vent.) Sweet] cultivars and lines. Of 19 arbitrary primer sequences tested, 16 revealed a high degree of polymorphism between the six most important genotypes with commercial significance, producing a total of 166 markers, of which 70% were polymorphic. Several primers (such as OPD-03 and OPM-07) were able to distinguish all tested genotypes from one another, showing an intracultivar consistency. These results indicate that RAPD analysis is a useful tool for establishing genetic diversity in this species as well as assisting in commercial protection of plant breeders' rights.

Free access

In order to gain an understanding of the capacity of severely shaded leaves to be productive in dense canopies, the effects of increased shading on morphology, dry-matter partitioning, and whole-plant net carbon exchange rate (NCER) were investigated on greenhouse-grown Vitis vinifera L. `Chardonnay' grapevines. Vines were subjected to whole-plant shading levels of 0%, 54%, 90%, and 99% of direct sun 3 weeks after potting. Data were collected 8 to 10 weeks after potting. Nonlinear regression was used to investigate the relationship of leaf morphological traits and organ dry weights to increased shading. Leaf size was maintained with increased shading to approximately the 90% shading level, while leaf fresh weight, volume, density, and thickness were immediately reduced with increased shading. Root dry weight was most affected by increased shading, and root to shoot ratio was reduced. When nonlinear regressions were produced for light response curves, light compensation point was reduced by approximately 49% by moderate shading, and 61% by severe shading. Shaded leaves approached the asymptote of the light response curve more quickly, and had reduced dark respiration rates, indicating that the morphological compensation responses by the vine allow shaded leaves to use available light more efficiently. However, the long-term ramifications of reduced root growth in the current year on vines with shaded leaves may be significant.

Free access