Letargo invernal en albaricoquero (Prunus armeniaca L.)análisis de diversos factores que afectan su evolución

Resum

Dormancy is a mechanism developed by temperate fruit trees grown in climates with well-differentiated seasons against the impact of low winter temperatures. The chill requirement fulfilment for each cultivar is essential for achieving an optimum development of vegetative and reproductive buds, which will affect timing and level of flowering and fructification. Although considerable progress has been achieved in the last few decades, large functional gaps of knowledge still exist regarding bud-dormancy induction, maintenance and release.Thus, the objective of this research work is to supply new evidence that may contribute to the general understanding of those aspects that remain unclear in the complex trait of dormancy, such as: i) the similarities and differences among different species or cultivars, as well as among locations with different climatic conditions; ii) the suitability of different methods for assessing chilling requirements for breaking of dormancy in mild winter areas; iii) the effect, sometimes uneven according to the literature, of different temperatures or combinations of temperatures over dormancy progression and dormancy release; iv) the efficiency of shading during endodormancy and chemical rest breaking agents for breaking dormancy in conditions of insufficient chill accumulation; and v) the identification of regions of genome (QTLs) controlling chilling requirements or flowering time, which is the first step to develop specific molecular markers for using molecular assisted selection in breeding programmes. The apricot species has been used as plant material not only due to the fact that few published studies have addressed apricot dormancy, but also because of the economical importance of this crop in the southeast of Spain. The development of low chill apricot cultivars is a neccesary step towards the introduction and growing of this species in marginal chill areas. With the purpose of obtaining representative results related to dormancy in the apricot species, a group of cultivars ranging the chilling requirement of apricot was studied. In addition, the studies were approached through experimentation in different climatic conditions that characterize the Mediterranean climate, in regions such as Murcia (Spain), Tuscany (Italy) and the Western Cape (South Africa).