Apples and pears are fruit crops particularly susceptible to cropping irregularities. A strong relationship has been observed between the effective pollination period (EPP) and the general cropping of the orchard. The EPP concept has also been proven to be a useful parameter to establish a relationship between the variation in the reproductive process and cropping behaviors. For apples and pears, a slow pollen tube growth has been shown to be the main limiting factor of the EPP in the traditional cooler temperate cultivation regions. However, while higher temperatures speed up the pollen tube growth, the expansion of these crops into warmer areas often results in failures of fruit set. Thus, with the aim to ascertain the main limiting factor responsible for fruit set failures in Mediterranean conditions we have evaluated the EPP for two consecutive years in `Agua de Aranjuez' pear, the main Spanish cultivar, by studying the stigmatic receptivity, pollen tube kinetics, and ovule development. Complete flower fertility was maintained for just 2 days after anthesis in both years. Pollen tube kinetics and ovule degeneration do not appear to limit flower receptivity. However, the stigmatic receptivity expressed as flowers with at least one receptive stigma, closely matches the duration of the EPP evaluated from fruit set experiments. This was consistent over the 2 years of experiments, in spite of the differences recorded in the EPP, suggesting that stigmatic receptivity is clearly the limiting factor of flower receptivity. This is the first report for stigmatic receptivity limiting the EPP in pears and suggests that stigmatic receptivity could be an important factor limiting pear flower receptivity and hence cropping performance under warmer conditions.

Com este trabalho, teve-se o objetivo de determinar a viabilidade de quatro lâminas de águas residuárias de origem urbana (75; 100; 125 e 150% da evapotranspiração da cultura) na produção de gérbera (Gerbera jamesonni), tipo comercial Rambo, comparando-se os resultados com os obtidos por meio da adoção do manejo convencional (adubação orgânica, química e irrigação com água de abastecimento equivalente a 100% da evapotranspiração). O experimento foi realizado em casa de vegetação, na Universidade Federal de Campina Grande, de fevereiro a julho de 2006, abrangendo um ciclo completo de produção. O delineamento experimental foi em blocos casualizados, com três repetições, e as variáveis monitoradas foram: número de botões florais emitidos e intervalo de emissão; número de flores colhidas e intervalo entre colheitas; diâmetro das flores e comprimento das hastes. Para as variáveis monitoradas, apenas o comprimento das hastes foi afetado significativamente pelas lâminas de água residuária aplicadas. A adoção do manejo com água residuária foi melhor que o convencional, em todas as variáveis, com exceção de comprimento das hastes, constatando-se que esse tipo de água constitui recurso importante no suprimento hídrico e de nutrientes para a cultura da gérbera, potencializando produtividade compatível ou melhor que o uso de técnicas de produção convencional. | The objective of the present study was to evaluate the viability of four depths (equivalent to 75; 100; 125 and 150% of crop evapotranspiration) of wastewater from urban origin in production of gerbera (Gerbera jamesonni), commercial type Rambo and contrast the results obtained with those adopting conventional management (organic and chemical manuring and irrigation with urban supply water equivalent to 100% evapotranspiration). The experiment was conducted on a greenhouse of Universidade Federal de Campina Grande - PB - Brazil, during February to July 2006, during a complete cycle of production. The experimental design consisted of randomized blocks with three replications. The variables monitored were number of flowers buds and emission interval, number of flowers collected and interval of harvest, diameter of flowers and length of flower stems. For the monitored variables, only length of flower stem presented significant effect among the depths of irrigation with wastewater. The adoption of management with wastewater showed superiority for the variables evaluated in relation to conventional management except the length of flower stem. These results demonstrate that the use of wastewater constitutes an important source for supply of nutrients and water to gerbera crop increasing the potential of compatible productivity or better than the conventional production techniques.

Com este trabalho, teve-se o objetivo de determinar a viabilidade de quatro lâminas de águas residuárias de origem urbana (75; 100; 125 e 150% da evapotranspiração da cultura) na produção de gérbera (Gerbera jamesonni), tipo comercial Rambo, comparando-se os resultados com os obtidos por meio da adoção do manejo convencional (adubação orgânica, química e irrigação com água de abastecimento equivalente a 100% da evapotranspiração). O experimento foi realizado em casa de vegetação, na Universidade Federal de Campina Grande, de fevereiro a julho de 2006, abrangendo um ciclo completo de produção. O delineamento experimental foi em blocos casualizados, com três repetições, e as variáveis monitoradas foram: número de botões florais emitidos e intervalo de emissão; número de flores colhidas e intervalo entre colheitas; diâmetro das flores e comprimento das hastes. Para as variáveis monitoradas, apenas o comprimento das hastes foi afetado significativamente pelas lâminas de água residuária aplicadas. A adoção do manejo com água residuária foi melhor que o convencional, em todas as variáveis, com exceção de comprimento das hastes, constatando-se que esse tipo de água constitui recurso importante no suprimento hídrico e de nutrientes para a cultura da gérbera, potencializando produtividade compatível ou melhor que o uso de técnicas de produção convencional.<br>The objective of the present study was to evaluate the viability of four depths (equivalent to 75; 100; 125 and 150% of crop evapotranspiration) of wastewater from urban origin in production of gerbera (Gerbera jamesonni), commercial type Rambo and contrast the results obtained with those adopting conventional management (organic and chemical manuring and irrigation with urban supply water equivalent to 100% evapotranspiration). The experiment was conducted on a greenhouse of Universidade Federal de Campina Grande - PB - Brazil, during February to July 2006, during a complete cycle of production. The experimental design consisted of randomized blocks with three replications. The variables monitored were number of flowers buds and emission interval, number of flowers collected and interval of harvest, diameter of flowers and length of flower stems. For the monitored variables, only length of flower stem presented significant effect among the depths of irrigation with wastewater. The adoption of management with wastewater showed superiority for the variables evaluated in relation to conventional management except the length of flower stem. These results demonstrate that the use of wastewater constitutes an important source for supply of nutrients and water to gerbera crop increasing the potential of compatible productivity or better than the conventional production techniques.