Citrus Rootstocks in Morocco: Present Situation and Future Prospects

Until the last decade, the Moroccan citrus industry has relied exclusively on sour orange as a rootstock. However, rootstock trials were initiated in the 1960s at the experimental farms of INRA. The major selection traits targeted at that time included yield and fruit quality, compatibility with clementine varieties and tolerance to Phytophthora gummosis, salt and limestone soils. In spite of the outstanding results of some rootstocks revealed by these trials, sour orange continues to be the main rootstock of choice of citrus farmers. Since the year 2000, after a long and intense debate among citrus industry stockholders, a vivid action was initiated to diversify citrus rootstocks in new plantings. While sour orange remained in use, trifoliate hybrids (Carrizo, Troyer, and C-35 citranges), C. volkameriana, and C. macrophylla started to increase in percentage, especially in large scale nurseries. In 2007, during a sanitary survey in the Loukous region Northwest of Morocco, Citrus tristeza virus (CTV) was detected at high incidence in many orchards. An intense effort is actually being devoted to promote the use of CTV tolerant rootstocks. Figures of how each one of these rootstocks has developed during the last 8 years are presented. A preliminary assessment of the impact of the rootstock shift on yield, quality and market reaction is discussed.