Time filter

Source Type

Gonzalez M.,Estacion Experimental de la Fundacion Cajamar | Cuevas J.,University of Almeria
Acta Horticulturae | Year: 2013

Cherimoya is a subtropical fruit tree indigenous to the inter-Andean valleys between Peru and Ecuador. Cherimoya dichogamy and the lack of efficient pollinators in Spain hinder natural fruit set, making hand pollination unavoidable. Cherimoya flowers are formed on current season growth and on 1-year-old shoots of different vigour. Hand-pollination allows selection of the more convenient flowers to be pollinated in order to obtain high quality fruits. Here, we have determined the frequency, fertility and flowering dates and patterns of the different kinds of shoots (high, medium and low vigour) found in cherimoya trees as the first step to modifying current pruning procedures. The results show that adult vase-trained trees traditionally-pruned have an equilibrated proportion of vigorous, semi-vigorous, and weak shoots. However, the number of flowers formed and the distribution of flowers along the wood were significantly different among the different kinds of shoots. Vigorous shoots formed an average of 65 flowers; semi-vigorous shoots produced an average of 36 flowers, while weak wood formed only 17 flowers per shoot. Flowering pattern was also different. Basal nodes of vigorous shoots formed a high proportion of flowers, while apical nodes did so in weak shoots. The flowering season extended from May to August with peak flowering occurring in mid-June with no differences in flowering dates among shoots. Based on these results, we recommend pruning to focus on encouraging the production of vigorous and semi-vigorous shoots able to sustain a crop load of 400 fruits per tree and to develop sufficient pollen-donor flowers. Handpollination is advised for flowers formed in the basal-central nodes of these shoots. A higher number of flowers per node did not diminish their size. © 2013 ISHS.

Gonzalez M.,Estacion Experimental de la Fundacion Cajamar | Cuevas J.,University of Almeria
Plant Systematics and Evolution | Year: 2011

Cherimoya (Annona cherimola) is a subtropical tree crop of Andean origin whose fruit set results extremely low in farming areas outside of its natural occurrence. The lack of efficient pollinators and dichogamy are often argued to be the main constraints resulting in this low reproductive success. Herein, we describe the reproductive barriers exhibited by this crop and whether wind and insects play a role in cherimoya pollination in Spain, the main region of cultivation. A. cherimola exhibits marked protogynous dichogamy with large differences in the duration of female (around 28 h) and male (>8 h) phases. Stigma receptivity and pollen release do not fully coincide with the morphological changes of the petals defining the female and male phases. Synchronization of sexual phases among different flowers from different trees of the same genotype was high during the whole blooming season. Effective herkogamy of approach type also limits pollen deposition within the same flower. Wind does not play any role in cherimoya pollination. Insect visitors to cherimoya flowers in Spain were found to be inefficient in transferring pollen grains. Cherimoya flowers do not reject self-pollen to achieve fertilization. A. cherimola shows preferential allogamy based on efficient dichogamy reinforced by elevated synchrony among flowers in their sexual phases. Herkogamy hampers autogamy, although pollen deposition by gravity in cherimoya pendulous flowers explains the reduced reproductive success observed in isolated flowers. © 2011 Springer-Verlag.

Hueso J.J.,Estacion Experimental de la Fundacion Cajamar | Cuevas J.,University of Almeria
Agricultural Water Management | Year: 2010

The successful application of postharvest regulated deficit irrigation (RDI) over ten consecutive years (from season 1999/2000 to season 2007/2008) confirms the sustainability of this strategy for producing 'Algerie' loquat. Postharvest RDI consisting in a reduction of watering (between 45 and 80% depending on the season) from early June until the end of August, improved loquat profitability by increasing fruit value and by reducing water consumption with respect to fully irrigated trees (control). The increase in fruit value in RDI trees was due to a consistent improvement in harvest earliness as a result of an earlier blooming. Water savings of around 20% did not diminish yield nor fruit quality. Water use efficiency in RDI trees rose by over 30%. Water productivity reached 9.5 € m-3 of water applied in RDI trees versus 6.6 € m-3 in control trees. The most noticeable effect of RDI on vegetative growth was a significant and progressive decline in trunk growth. The canopy volume seems to be strongly influenced by pruning and no significant effects were detected in this parameter. Our results confirm the suitability of RDI in loquat and the economic benefits of saving water during the summer. © 2009 Elsevier B.V. All rights reserved.

Gonzalez M.,Estacion Experimental de la Fundacion Cajamar | Cuevas J.,University of Almeria
Acta Horticulturae | Year: 2012

Cross-pollination response in olive varies according to the genotype, environment and management. The index of self-incompatibility (ISI) measures such cross-pollination response in terms of fruit set. Here, we present the comparison of ISI values of 'Arbequina' trees located in two different sites (Tabernas and La Cañada de San Urbano, Almería, Spain) and years (2002 and 2003). The results show that crosspollination response differed extraordinarily depending on the site and the year. ISI in La Cañada was 0.03, while in Tabernas, ISI was 1.51 (year 2002) and 0.69 (year 2003) which allows classifying 'Arbequina' either as totally self-incompatible (La Cañada) or as self-compatible (Tabernas). No clear relation could be established among ISI values and parameters linked to flowering intensity and quality. At this regard, flowering levels measured by the number of inflorescences per node and quality estimated by the percentage of fertile inflorescence did not differ among locations and years. Nonetheless, 'Arbequina' trees located in La Cañada de San Urbano (ISI=0.03) produced more flowers per panicle (p=0.05) and presented a lower percentage of hermaphrodite flowers (p=0.06); both parameters were negatively related (r=-0.73, p<0.01). Cross-pollination response of individual 'Arbequina' trees was positively related to the number of flowers per inflorescence fitting an exponential curve (r2=0.37, p<0.05). The results confirm that cross-pollination response in olive is extremely variable even for a single genotype and suggest that this variability is linked to flower fertility.

Gimenez C.,University of Cordoba, Spain | Gallardo M.,University of Almeria | Martinez-Gaitan C.,University of Almeria | Stockle C.O.,Washington State University | And 2 more authors.
Irrigation Science | Year: 2013

The VegSyst simulation model was developed to assist with N and irrigation management of sweet pepper grown in plastic greenhouses in the Mediterranean Basin. The model was developed for use in an on-farm decision support system with the requirement for readily available input data. Dry matter production (DMP), crop N uptake and crop evapotranspiration (ETc) are simulated on a daily basis. DMP is calculated from daily fraction of intercepted photosynthetically active radiation (PAR), PAR radiation, and radiation-use efficiency. Fraction of intercepted PAR is calculated from relative thermal time. Crop N uptake is calculated as the product of DMP and N content which is described by a power function of DMP. ETc is the product of daily reference evapotranspiration (ETo) using an adapted Penman-Monteith equation, and a daily simulated crop coefficient value. The VegSyst model for soil-grown, greenhouse pepper was calibrated in one crop and validated in three different crops. In the validation, the model accurately simulated crop growth, N uptake and ETc. Relative to measured values, simulated DMP at final harvest was 0.89-1.06, and crop N uptake was 0.97-1.13. Simulated cumulative ETc for complete crops was 0.95-1.05 of measured values. © 2012 Springer-Verlag.

Discover hidden collaborations