The development of redskinned apples adapted to the warm climates of South European countries

Many red-skinned apple cultivars grown under warm summer conditions do not redden as much as those grown in locations with cooler summer temperatures. Reflective films and over-tree sprinkler irrigation have been used to mitigate the issue. However, the most efficient strategy is to breed new cultivars that have a high genetic potential for fruit colour development under warmer climates. New cultivars selected for their adaptation to such climates are being bred by a joint Institut de Recerca i Tecnologia Agroalimentàries-Plant & Food Research (IRTA-PFR) breeding programme. Understanding the physiological and genetic control of the response to warm orchard temperature is crucial for developing new tools for more efficient breeding of red-skinned apple cultivars. We manipulated fruit skin temperature by heating and cooling ‘Royal Gala’ fruit in orchards in New Zealand and Spain and measured the expression of the genes regulating red pigmentation. Evidence of down-regulation of the main activator of red pigmentation (MYB10) was demonstrated, and this gene is linked to a locus controlling the red-skinned phenotype. A marker based on MYB10 was developed and is now used for marker-assisted breeding of new apple cultivars suited to warm conditions

Prunus hybrids rootstocks for flat peach

Peach (Prunus persica L.) is the most important stone fruit tree grown in Spain and is the second most important fruit crop in Europe. The influence of eight Prunus rootstocks (GF-677, Krymsk® 86, PADAC 97-36, PADAC 99-05, PADAC 9912-03, PADAC 0024-01, PAC 0021-01 and PAC 0022-01) on vigor, yield and fruit quality traits of 'UFO 3' flat peach cultivar was studied. The highest trunk cross sectional area was exhibited by GF-677 and the lowest by PADAC 99-05, while intermediate values were found on the other rootstocks. The highest yield efficiency was found on PADAC 99-05, PAC 0021-01, PAC 0022-01 and PADAC 0024-01 and the lowest was shown on Krymsk® 86. The fruit quality parameters measured were color, fruit and stone weights, equatorial diameter, pulp thickness, pulp yield, firmness, pH, soluble solids content and titratable acidity. 'UFO 3' grafted on GF-677 resulted in the largest fruit weight, while the smallest was on PADAC 99-05. Fruits of 'UFO 3' showed a tendency to have higher firmness, higher red colored skin and RI when grafted on PADAC 99-05

Vigor, floração, produção e qualidade de pêssegos 'Chimarrita' e 'Maciel' em função de diferentes porta-enxertos Vigour, flowering, yield and quality of 'Chimarita' and 'Maciel' for different rootstocks

O objetivo deste trabalho foi avaliar o vigor, a floração, a produção e a qualidade de pêssegos das cultivares 'Chimarrita' e 'Maciel' sobre oito porta-enxertos. O diâmetro do tronco, acompanhamento da floração, produção e qualidade de pêssegos foram os parâmetros estudados nas safras de 2008 e 2009, na Universidade Federal de Pelotas, Pelotas, RS. De acordo com os resultados obtidos, as cultivares 'Chimarrita' e 'Maciel', enxertadas sobre Umezeiro, apresentam menor vigor e sintomas de incompatibilidade quando comparadas com a enxertia nos demais porta-enxertos. A floração de ambas as cultivares foi influenciada pelos porta-enxertos, podendo retardar ou antecipar o início e a plena floração em até cinco dias. A cultivar 'Maciel' enxertada sobre Tsukuba 1 foi a mais produtiva e a cultivar 'Chimarrita' apresentou maior produção quando enxertada sobre Aldrighi e Capdeboscq. O porta-enxerto Umezeiro proporcionou frutos com maior relação SS/AT para a cultivar 'Maciel' e, para 'Chimarrita', os pêssegos apresentaram maior conteúdo de sólidos solúveis.<br>The objective of this research was to evaluate the vigour, flowering time, yield and quality of peach fruits from the cultivars 'Chimarrita' and 'Maciel' grafted on eight rootstocks. The experiment was carried out at the Faculdade de Agronomia Eliseu Maciel (Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brazil), during the 2008 and 2009 years. The obtained results showed that the 'Maciel' and 'Chimarrita' cultivars grafted on Umezeiro are less vigorous when compared to that grafted on other rootstocks, and showed signals of incompatibility. The flowering of the 'Chimarrita' and 'Maciel' peach cultivars is influenced by the rootstocks that can retard or anticipate the beginning and the full flowering in up to five days; the 'Maciel' cultivar grafted on Tsukuba 1 is the most productive and, for 'Chimarrita' the production is greater when grafted on Aldrighi and Capdeboscq. The rootstock Umezeiro provides fruit with higher SS/TA for 'Chimarrita' and 'Maciel' peach cultivars have a higher content of soluble solids