Advances in Fruit Breeding in Eastern Canada - Role of Phytochemicals in Designing Specialty Fruits S. Khanizadeh 1 , R. Tsao 2 , D. Rekika 1 , R. Yang 2 , M.T. Charles 1 and H.P.V. Rupasinghe 3 1 Horticultural Research and Development Centre, Agriculture and Agri-Food Canada, 430 Gouin Blvd., St-Jean-sur-Richelieu, Quebec, J3B 3E6, Canada 2 Food Research Program, Agriculture & Agri-Food Canada, 93 Stone Road West, Guelph, Ontario N1G 5C9, Canada 3 Tree Fruit Bio-product Research Program, Nova Scotia Agricultural College, P.O. Box 550, Truro, NS, B2N 5E3, Canada Keywords: total phenolics, antioxidant activity, strawberry, apple, genetics Abstract High dietary intake of fruits and vegetables rich in phytochemicals, particularly those with antioxidant activity, has been linked to reduced risks of many chronic diseases including cancer and cardiovascular diseases. Value-added foods and nutraceuticals containing such bioactive phytochemicals have been popular and made available in the market. Many factors affect the phytochemical concentration in fruits including farming practices, environmental factors and microclimate including the production methods, fruit maturity, and pre- and post- harvest handling of the fruits, but the genetic factor probably has the greatest effect on the biosynthesis of antioxidant secondary metabolites. A large variation of antioxidant concentrations exists within apple, strawberry, and raspberry cultivars and breeding lines, and it is possible to use this as a marker to develop new lines. The increase and/or decrease in phytochemical can both be useful in designing fruits: elevated concentration of antioxidants could extend the shelf life and reduce the incidence of diseases; and modulation of specific antioxidants can be use as a tool to change the specific quality characteristics of a fruit. Several examples like new raspberries and strawberries rich in phytochemical and post-cut non-browning apples low in certain antioxidants will be presented and discussed. INTRODUCTION The presence of phenolic compounds in fruits has been studied fairly well. Phenolics not only are important in plant defence mechanisms but they also play a major role on quality, colour, and taste of fruits and juice (Bushway et al., 2002; Robards et al., 1999; Van der Sluis et al., 2002; Wang et al., 1994). Antioxidants such as vitamin C are not the only compound responsible for antioxidant capacity and the majority of the antioxidant of fruits are originated from polyphenols (Eberhardt et al., 2000). Apples have been reported to contain various antioxidative phenolic compounds and their composition changes with degree of fruit maturity, cultural practices, environmental factors, storage period, and processing (Robards et al., 1999) but the genetic variation remains to be the most important factor (Khanizadeh et al., 2007). The significant variation in antioxidant capacity and total phenolic compounds of selected strawberry (Ehsani-Moghaddam et al., 2006; Rekika et al., 2005; Tsao et al., 2006) and apple (Tsao et al., 2005, 2006) cultivars clearly shows the potential value of certain new cultivars and advanced lines as parents in a breeding program. Apples and strawberries are the most important fruits in Canada and several other countries. A major part of the production is consumed fresh, but a large part of it is processed (Khanizadeh et al., 2000; Khanizadeh and DeEll, 2005). During the last couple of years, our research team quantified individual phenolic compounds of selected advanced apple, strawberry, and raspberry lines in order to evaluate their total phenols and antioxidant activity. This information was used as markers in our laboratory to examine their role in disease resistance and extension of shelf life and to name new lines 205 Proc. XII th Eucarpia Symp. on Fruit Breeding and Genetics Eds.: R. Socias i Company et al. Acta Hort. 814, ISHS 2009