Evaluation of resistance of ten citrus rootstocks resistant to tristeza regarding the water deficit [Ivaluation de la résistance de dix porte-greffes d'agrumes résistants à la tristeza vis-à-vis du déficit hydrique]
Beniken L.,Institute National Rech Agron Inra Maroc |
Beqqali M.,Institute National Rech Agron Inra Maroc |
Dahan R.,Institute National Rech Agron Inra Maroc |
Benkirane R.,Université Ibn Tofail |
And 4 more authors.
Fruits | Year: 2011
Introduction. In Morocco, citriculture faces up an increasing combination of biotic (Citrus tristeza virus (CTV)/Phytophthora spp) and abiotic stresses (salinity, alkalinity and drought). Most of these constraints should be individually managed by adapted rootstock choice. However, the spread of CTV in the Mediterranean Basin will soon prohibit the use of the traditional sour orange rootstock, which currently provides sufficient tolerance to salinity and alkalinity. Therefore, the selection of new citrus rootstocks becomes urgent. Our study sought to investigate the effect of different water regimes on growth of ten citrus rootstocks: citrange Carrizo (France), citrange Carrizo (Morocco), citrange Troyer, citrange Yuma, Citrus volkameriana; two Poncirus trifoliata of different origins, citrumelo, Mand. Sunki × Poncirus trifoliata, and Poorman. Materials and methods. For each rootstock, three months old seedlings were grown in plastic pots (0.5 L) in a greenhouse at El Menzeh, INRA, Morocco; they were subjected to three water regimes [(100%, 75% and 50%) moisture field capacity (Hcc) of the substrate]. The experiment was arranged in a split-plot design with three treatments. The morphological parameters measured were the plant height and dry and fresh matter accumulation. Physiological parameters studied were the Relative Water Content, transpiration rates and chlorophyll, soluble sugars and proline contents. Results. The morphological and physiological parameters were affected by the intensity of water stress applied. However, rootstocks behaved differently regarding to this constraint. Water stress induced an increase in the proline and soluble sugars content in the rootstock leaves. Conclusion. Water stress significantly affects the physiological and morphological characteristics of citrus rootstocks and, in conditions of extreme water deficit (50% Hcc), a differential behavior of the rootstock was found. Based on our results, the rootstocks Carrizo citrange (Morocco) and Poorman present the best overall ability to withstand water stress. © 2011 Cirad/EDP Sciences.