Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 42 Page 43 Page 44 Page 45 Page 46 Page 47 Page 48 Page 49 Page 50 Page 51 Page 528 I EUROPEAN SEED I EUROPEAN-SEED.COM ES: How important are disease resistances? All breeders agree that Fusarium and powdery mildew resist- ance are basic and essential in modern melon varieties, and add that resistance to diseases and pests are an integral part of the components that benefit commercial yield by giving a better yield security, lower waste and a better fruit quality. Kuijpers explains that new problems are insects and insect-transmitted viruses. Recent problems with white fly transmitted viruses like Cucurbit yellow stunting disorder virus (CYSDV) and Tomato leaf curl New Delhi virus (ToLCNDV) receive considerable breeding resources. Chartier says resistances are “equally important to other traits involved in yield, such as root strength, vigour, plant cover, fruit set and fruit size distribution.“ Den Hertog agrees, as because of the intensive use of the agricultural land in France and Spain for melons, the risk of a soil disease like Fusarium is relatively high. “To develop the necessary resistances, we have a high-tech phytopathological centre at our disposal close to our head office in De Lier, The Netherlands,” he explains. “Moreover, we have local facilities for disease testing at our melon breeding locations in Spain and France. This enables the melon teams in these countries to be quick and flexible in terms of practical research. “ De Langen: “For us, the most important diseases resist- ances are: • Fungi: powdery mildew (6 races), Fusarium oxysporum f.sp. melonis (4 races), Scab and Gummy Stem Blight (GSB). • Viruses: Melon Necrotic Spot Virus, Cucumber Mosaic Virus, Watermelon Mosaic Virus, Zucchini Yellow Mosaic Virus • Pests: Aphid (Aphis gossypii) • Bacteria: Pseudomonas syringae pv. aptata "For this we want to create disease resistance packages accord- ing to growing conditions (e.g. for the French market we are offering varieties combining resistances to Powdery mildew race 3-5, Fusarium oxysporum race 1-2 and Aphis gossypii. We are also working on ‘new’ diseases and pests like new races of pow- dery mildew and Fusarium oxysporum race 1-2." Also, Chartier is adamant about packaging the resistances. “Disease resistances combined in packages (e.g. Powdery Mildew/Fusarium oxysporum melonis 1-2 and Aphis gossypii resistance) in the new genetics must deliver significant improve- ment for crop management. Field-holding, to limit the picks, broad adaptability and shelf life improvement are some others traits focused to limit the growers economics.” Foncelle says the main steps for developing a melon variety are: the creation of variability; parental line development and fixation; crosses to make many hybrid combinations for test- ing. “Then we go through what we call early stage selection and hybrid late stage selection.” ES: And what about shelf life? De Langen states shelf life is a very important trait in melon. “Originally, most of the cultivated melon types were climac- teric, which means that at maturity they had a peak in ethylene production that triggers a specific post-harvest behaviour: high aroma, but low shelf life because of loss of firmness, internal flesh breakdown, changes of external colour, loss of sugar, etc.,” he says. “Breeders have introduced shelf life genes from exotic germplasm in cultivated materials since the 1980s. Most of these genes are involved in ethylene metabolism/perception in fruits, blocking partially or completely ethylene production or per- ception and generally low aroma/high firmness/high sugar. By choosing the right combination of genes, it is possible to create a range of shelf-lives, according to grower/shipper’s needs: long distance shipping (one month or more) to medium/short dis- tance (one week), but with sufficient aroma for the consumer.” Pleguezuelo feels the same way, adding shelf life is a “very important trait for traders and also for consumers. A good bal- ance between eating quality and shelf life is absolutely key.” Kuijpers also agrees. “Melon can be found year-round in the shops, but the main growing areas are not able to provide a year-round product. So in the off-season the product comes from Central and South America. To survive the journey, shelf life is crucial.” ES: Most of the modern melon varieties are hybrids. Does this provide you with any specific challenges or opportunities as compared to breeding OP melon? Foncelle says breeding a hybrid variety is providing us with more opportunities to combine traits in a single variety as compared to the development of an OP variety. Chartier adds that nowadays, nearly all commercial melon varieties are F1 hybrids. “Open Pollinated (OP) varieties are still grown in some areas in North Africa and Turkey, but gradually they are moving to hybrids as well. HM.CLAUSE develops only F1 hybrids.” Process of melon breeding the different steps: • Definition of goals, traits of interest (1 year minimum), followed by conventional breeding methods with the use of state-of-the-art research tools in pathology, cellular biology, biochemistry and molecular marking. • Pool / population creation (1 year minimum) • Line selection / evaluation – technological intervention to speed up cycles (1 to 3 years) • Hybrid creation /evaluation (1 year minimum) • Development (1 year minimum) • Registration / production / IP aspects / Seed Quality aspects (1 year minimum) • On average it takes about 6-8 years minimum to launch a successful variety. Source: F de Langen, HM. CLAUSE HM.CLAUSE melon breeding greenhouse in Saint Remy de Provence Research center (France).