El cultivo in vitro de embriones y óvulos en la mejora de variedades tempranas de melocotonero

En las últimas décadas, la inmensa mayoría de los programas de mejora genética de melocotonero se han enfocado en la obtención de variedades de maduración temprana o extratemprana...Colaboración en la web: Interempresas.ne

Morphoagronomic characterization of landraces and local germplasm in the Spanish National Pear Bank in Zaragoza: abstract

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Agro-morphological diversity of local and international accessions of the Spanish Pear Germplasm Bank in Zaragoza

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Augmentation des besoins en froid et en chaleur pour la floraison des nouveaux cultivars d’amandier

Almond (Prunus amygdalus (L.) Batsch) has been considered the earliest blooming fruit species, although it has become the species with the widest blooming range of all deciduous fruits after the release of the newly bred cultivars. Blooming of any cultivar takes place once its chill and heat requirements have been satisfied. Estimation of chill and heat requirements for blooming is very complex, due to the difficulty of assessing the theoretical date of transition from endodormancy to ecodormancy, when quantification of chill requirements ends and quantification of heat requirements starts. This date may be assessed by a statistical method based on the different effect of temperatures on blooming date depending on their incidence during endodormancy or ecodormancy. This method has been applied to obtain the chill and heat requirement of the almond cultivars released by the Centro de Investigación y Tecnología Agroalimentaria de Aragón (CITA). G-2-25 is an elite selection from the Zaragoza breeding programme, characterized by a very late blooming time. It shows 503 Utah CU, much higher than the other almond cultivars released by the CITA, such as 329 CU in 'Felisia' or 353 CU in 'Aylés' and 'Belona'. It also shows a very high heat requirement, with 10233 Utah GDHºC, higher than 7221 GDHºC in 'Blanquerna' or 9465 GDHºC in 'Felisia'. These results show that the combined increase in chill and heat requirements in a genotype may ensure a late blooming season in all climatic conditionsL'amandier (Prunus amygdalus (L.) Batsch) a été considéré l'espèce fruitière à floraison la plus précoce, bien qu’elle soit devenue l'espèce avec l’intervalle de floraison le plus étendu de toutes les espèces fruitières après l'introduction des nouveaux cultivars améliorés. La floraison de tout cultivar vient quand les besoins en froid et en chaleur ont été satisfaits. L'estimation des besoins en froid et en chaleur pour la floraison est très complexe, étant donné la difficulté d'établir la date théorique de transition entre l'endo-dormance et l'éco-dormance, quand la quantification des besoins en froid finit et que commence la quantification des besoins en chaleur. Cette date peut être déterminée par une méthode statistique basée sur l’effet différent des températures sur la date de floraison en fonction de leur incidence pendant l'endo-dormance ou l'éco-dormance. On a appliqué cette méthode pour obtenir les besoins en froid et en chaleur pour les cultivars introduits par le Centro de Investigación y Tecnología Agroalimentaria de Aragón (CITA). G-2-25 est une sélection élite du programme d'amélioration génétique de Zaragoza, caractérisée par une date de floraison très tardive. Elle a montré 503 Utah CU, beaucoup plus que les autres cultivars d'amandier obtenus par le CITA, comme 329 CU pour 'Felisia' ou 353 CU pour 'Aylés' et 'Belona'. Elle a aussi montré de grands besoins en chaleur, avec 10233 Utah GDHºC, une valeur beaucoup plus élevée que 7221 GDHºC pour 'Blanquerna' ou 9465 GDHºC pour 'Felisia'. Ces résultats montrent qu’une augmentation combinée de besoins élevés en froid et en chaleur peut assurer, pour un génotype, une époque de floraison tardive dans toutes les conditions climatique

Stability of the almond blooming date in a changing climate

Although global warming is increasing the medium air temperature over time, this negative temperature trend cannot be yet appreciated in some areas. Analysis of air temperatures in the Ebro Central Valley (Zaragoza, Spain) during the last 24 years shows drastic changes in temperature during winter and spring and high variability among years. Under these conditions, there is an excess of chill and most almond cultivars satisfy their chilling requirements very early, during the first two weeks of December, when endodormancy finishes. As a consequence, bloom dates are ruled mainly by the heat requirements. Early-blooming almond cultivars showed a higher variation in dates of full bloom because they are more dependent on warm temperatures during January and February, where heat accumulation is slower. Late-blooming cultivars showed more stable blooming dates because their greater heat requirements are quickly satisfied by the higher March temperatures. Cultivars with high cold and heat requirements are desirable for stable late blooming. This characteristic and its relationship with local climatic conditions is essential in choosing cultivars to be planted in a given region, especially to avoid frost risks.Peer ReviewedPrunus amygdalusbreedinggermplasmdormancyPublishe

Kernel quality of local spanish almond cultivars: provenance variability and end uses

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Agroclimatic Requirements of Traditional European Pear (Pyrus communis L.) Cultivars from Australia, Europe, and North America

Flowering in temperate fruit trees depends on the temperatures during the previous months; chill is required to overcome endodormancy, and then heat exposure is needed. These agroclimatic requirements are cultivar-specific and determine their adaptability to the growing area and their response to climate change. We aim to estimate the agroclimatic requirements of 16 traditional cultivars of European pears grown in Zaragoza (Spain). We used Partial Least Squares regression analysis to relate 20-year records of flowering dates to the temperatures of the 8 previous months. This approach allowed us to establish the chilling and forcing periods, through which we quantified temperatures with three models for chill accumulation (Chilling Hours, Utah model, and Dynamic model) and one model for heat accumulation (Growing Degree Hours). The results indicated very little difference in the chilling and forcing periods. Chill requirements ranged from 43.9 to 49.2 Chill Portions; from 1027 to 1163 Chilling Units; and from 719 to 774 Chilling Hours. Heat requirements ranged from 6514 to 7509 Growing Degree Hours. Flowering dates were mainly determined by the temperatures during the chilling period. This means that reductions in winter chill caused by global warming in many regions could cause flowering delays or even failures in the fulfillment of chill requirements.Publishe