Audrey Levasseur

Antioxidant capacity in June-bearing and day-neutral strawberry

The present study was carried out to estimate the crude, hydrophilic and lipophilic antioxidant content of known and new advanced selections among June-bearing and day-neutral genotypes using Trolox equivalent antioxidant capacity method. Crude, hydrophilic and lipophilic extractions were prepared using 25 g of frozen fruits from each sample. In June-bearing strawberries, significant differences were observed among crude, hydrophilic and lipophilic antioxidant values of different selected genotypes. Mean of crude, hydrophilic and lipophilic antioxidants in June-bearings were estimated to be 20.4, 13.4 and 0.5 μmol TE g-1 FW, respectively, which were higher than those of the day-neutral genotypes (i.e., 13.2, 9.4 and 0.3 μmol TE g-1 FW). The present study revealed the importance of genetic background for determining the antioxidant potential in selected June-bearing genotypes and the possibility of production of new strawberry cultivars with higher levels of antioxidant capacity through breeding programs. ...

The Use of a Bud Freezing Technique to Determine the Hardiness of 20 Grape Genotypes

Abstract Pencil thick canes (-8 mm) from 20 different grape cultivars were harvested at 2 different dates in the fall (October and November). The cultivars had previously been classified as hardy (group A), semi-hardy (group B) or tender (group C). Individual bud sections of the canes were placed in a refrigeration unit and subjected to sequential freezing temperatures of 19°F, 5°F, −8°F and −22°F (−7°C, −15°C, −22°C, and −30°C) for 24 hours at each temperature. Samples were removed each day to evaluate the survival of buds. Results for the samples taken in October showed that almost 100% of the buds were killed once they were subjected to −8°F (−22°C) or colder. The critical temperature appeared to be 5°F (−15°C), where there was a marked difference in survival between the 3 groups of genotypes: percent mortality was 46%, 68% and 94% for groups A, B, and C, respectively. In November, most of the hardy cultivars showed little adverse effects at −8°F (−22°C), whereas the tender cultivars suffered the most injury with percent mortality of 25% and 83%, respectively.

Soluble Solids, Acidity, Canopy Fruit Distribution, and Disease Susceptibility of Selected Grape Cultivars in Quebec

ABSTRACT Twenty grapevine genotypes (‘Chancellor’, ‘Delisle’, ‘ES-6–12–28’, ‘ES-4–7–25’, ‘GR-7’, ‘Hibernal’, ‘Sabrevois’, ‘Kay Gray’, ‘Lucie Kuhlmann’, ‘Michurinetz’, ‘Okanagan Riesling’, ‘Prairie Star’, ‘St. Croix’, ‘St. Pepin’, ‘Seyval Noir’, ‘Seyval Blanc’, ‘SV-18–307’, ‘Vandal-Cliche’, ‘Vidal Blanc’, and ‘Siegerrebe’) were evaluated under different winter protection methods in Frelighsburg, Quebec, Canada. The effects of these methods on soluble solids, acidity, fruit canopy distribution, and susceptibility to diseases were evaluated. Significant differences in juice composition was observed among the tested cultivars, and a significant interaction was observed between cultivar and sampling date, indicating that the effects of sampling date and cultivar are not independent. SSC/acid ratio increased with a corresponding decrease in acidity and the hardy and semi-hardy cultivars Lucie Kuhlmann, Michurinetz, and Geneva Red produced the highest °Brix values. None of the tender cultivars had values exceeding 19.5 °Brix. A decrease in acidity was observed for all cultivars as ripening progressed except for ‘Seyval Blanc’, ‘St. Pepin’, ‘St. Croix’, and ‘SV-18307’, which showed little or no reduction in acidity during the last three sampling dates. Under the climatic conditions observed in this study, ‘Prairie Star’, ‘ES-4–7–25’, ‘Geneva Red’, ‘St. Pepin’, ‘Delisle’, ‘ES-6–12–28’, ‘Vandal Cliche’, ‘Kay Gray’, ‘Lucie Kuhlmann’, ‘Okanagan Riesling’, and ‘SV-18–307’ had acceptable SSC and TA values. No clusters were observed at a wire level above 175 cm in any of the winter protection systems. In the M1 and M2 treatments, almost all the cultivars produced the highest proportion of clusters at a height of 80 to 125 cm and minimum fruit clusters close to the ground. Unlike the M1 and M2 methods, the M3 winter protection approaches produced a wide distribution of fruit in the canopy. ‘Michurinetz’ had the highest powdery mildew infection, followed by ‘Siegerrebe’ and ‘Lucie Kuhlmann’, whereas ‘Prairie Star’, ‘ES 4–7–25’, ‘St. Croix’, ‘St. Pepin’, ‘Vandal Cliche’, ‘Hibernal’, ‘Okanagan Riesling’, and ‘Seyval Noir’ exhibited low susceptibility. No powdery mildew symptoms were noted in ‘Sabrevois’, ‘Delisle’, ‘Kay Gray’, ‘ES-6–12–28’, ‘Chancellor’, ‘SV-18307’, or ‘Seyval Blanc’.

'SJM15' Apple Rootstock

ABSTRACT The ‘SJM15’ Apple Rootstock is s a new dwarfing apple rootstock developed at the Agriculture and Agri-Food Canada (AAFC) Research Station, St-Jean-sur-Richelieu, Quebec. It produces dwarf trees equal to or slightly smaller than ‘Ottawa 3’ (O.3) and ‘Malling 9’ (M.9). It was released because of its superior hardiness, ease of propagation, and better efficiency compare to ‘O.3’.