ISHS Acta Horticulturae 121: VII Symposium on Apricot Culture and Decline
CHILLING REQUIREMENTS FOR BLOOMING IN APRICOT TREE, DETERMINED EITHER BY A STATISTICAL METHOD OR BY AN EXPERIMENTAL METHOD AND VALUED ACCORDING TO AN EXPONENTIAL CONCEPTION OF TEMPERATURE ACTION |
| Authors: | J.M. LEGAVE, G. GARCIA |
| Abstract:
Easy methods for estimating the depth of flower buds dormancy during the rest period can be useful to growers. For instance in climatic conditions where there are frost dangers, easy valuations of chilling requirements can lead growers in order to settle each year the best time of starting frost protection. In the same way valuations of chilling requirements peculiar to each cultivar or hybrid can be useful to breeders in order to resolve various problems of climatic adaptability. Whatever the object may be, valuations of chilling requirements are useful only if these valuations are nearly constant in very different climatic conditions. For this essential reason still frequent valuations in sums of hours when mean temperature is lower than about 7°C must be finally forsaken (Crossa-Raynaud, 1955; Bidabé, 1967; Richardson et al., 1974). Therefore in the case o a early blooming tree as apricot we thought it was interesting to study a new model for estimating chilling requirements proposed by Bidabé (1965), on account of his relatively constant results in very different climates for apple tree. Valuations of chilling requirements correlatively set the problem of defining the break of dormancy. Indeed it's a gradual process in which several stages may be discerned in relation to increasing chill periods (Carraut, 1968). Consequently a valuation of chilling requirements required for each stage may be useful to growers or breeders. Therefore in this study we researched the break of dormancy through 2 methods having very different conceptions. | |
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