International Society for Horticultural Science ROSA - Responsive Online System for Acta Horticulturae submission and review This submission belongs to: XV Eucarpia Symposium on Fruit Breeding and Genetics Acta Below is the abstract for symposium nr 620, abstract nr 135: Horticulturae Home Title: Login Logout Improvement of salt tolerance and resistance to Status gummosis in rootstocks through controlled hybridization

ISHS Home Author(s): ISHS Contact Anas Fadli, UR APCRP, INRA, BP 257, Kenitra, Morocco;

ISHS online [email protected] (presenting author) submission Dr. Samia Lotfy, UR APCRP, INRA, BP 257, Kenitra, Morocco; and review [email protected] (co-author) tool Mr. Abdelhak Talha, UR APCRP , INRA, BP 257, Kenitra, Morocco; homepage [email protected] (co-author) Calendar Dr. Driss Iraqi, UR de Biotechnologie, INRA, BP 415, Rabat, Morocco; of [email protected] (co-author) Symposia Dr. María Angeles Moreno, Estación Experimental de Aula Dei, CSIC, Authors Av. Montañana 1.005, Zaragoza, Spain; [email protected] (co- Guide author) Prof. Dr . Rachid Benkirane, Laboratoire BBPP, Département de Biologie, Faculté des Sciences, Université Ibn Tofail, Kenitra, Morocco; [email protected] (co-author) Dr. Hamid Benyahia, UR APCRP, INRA, BP 257, Kenitra, Morocco; [email protected] (co-author)

Preferred presentation method: Poster

Abstract body text: The sustainability of Mediterranean citriculture depends largely on the use of rootstocks that provide a better adaptation to biotic and abiotic constraints, as well as a good graft-compatibility with commercial . In the absence of rootstocks meeting all these criteria, the management of the available diversity and the selection of the desirable traits are necessary. In the present work, we conducted a controlled pollination program involving four different rootstock genotypes that belong to the germplasm collection of INRA Morocco. These genotypes included cv. ‘Winter Haven’ (Citrus paradisi Macf. x Poncirus trifoliata L. Raf.), Sunki mandarin (Citrus sunki), Cleopatra mandarin (Citrus reshni), and (Citrus grandis). The breeding program resulted in the development of a population of 199 seedlings, 31 of which expressed marked morphological traits of the male parent. Molecular characterization of these 31 genotypes using flow cytometry and microsatellite markers helped to determine their ploidy level and to confirm the parental origin of the zygotic seedlings. On the other hand, the phenotypic characterization of the potential hybrids by early screening tests revealed heterogeneous responses to salinity and Phytophthora attacks. An interesting combination of salt tolerance traits (chloride exclusion, high relative growth, high stomatal conductance) with resistance to Phytophthora gummosis was observed in two citrumelo hybrids, H56 and H92, which seem therefore to be qualified for use in salt and Phytophthora affected regions as a replacement for the CTV-susceptible rootstock, sour .

Keywords: Citrus, salinity , Phytophthora diseases, conventional breeding, phenotypic characterization