Inheritance of floral abortion in progenies of "Stark Early Orange" apricot

In apricot flower bud abortion is a main component of varietal adaptability under climatic conditions of French and Italian growing areas. The 'Stark Early Orange' (SEO) variety is mainly used in breeding programs as genetic resource for resistance to plum pox virus. Despite very high flower bud initiation on lateral shoots, 'SEO' is unfruitful under Mediterranean growing areas because of excessive abortion. Thus a preliminary study of the inheritance of floral abortion was carried out through the observation of three segregant progenies obtained from crossing between 'SEO' and three fruitful cultivars. Each progeny was evaluated during at least two consecutive years using the same methodology in France and in Italy. Preliminary and similar results support the hypothesis that floral abortion trait is transmitted through a polygenic control. Moreover the high susceptibility of 'SEO' regarding floral abortion could be transmitted with an important dominance effect, regardless of its use as male or female parent