Impact of the Salt Stress on the Agronomic Potential of the Moroccan Populations of Alfalfa (Medicago sativa L.) Under the Field Conditions of Marrakesh

Abstract

Salinity is one of major abiotic factors inhibiting forage yield in many regions of Morocco. This study focused on the assessment of the behavior of Moroccan alfalfa ( Medicago sativa L.) under salt stress. The experiment was carried out in the field at the experimental station of the National Institute for Agronomical Research (INRA)-Saâda, Marrakech. Four Moroccan populations, Adis (PO1), Tata (PO2), Demnate1 (PD1) and Demnate2 (PD2) were used and one Australian variety Siriver (T) as reference. The trial received 120 mM NaCl, three successive cuts were adopted and several traits related the agronomical potential under stress were assessed. Results showed that the salt treatment significantly reduced growth and forage yield, with significant variation between the studied genotypes. However, PO1 and PO2, the oasis populations presented the lowest dry matter reductions of 14.4% and 17.6% respectively under stress. Indeed, they presented the highest relative water content (RWC), chlorophyll (Chl) and total soluble sugars (TSS) contents as well as the highest nitrogen (N) content in their leaves. Thus, these populations were qualified as more salt tolerant than Siriver and the mountains populations (PD1 and PD2) and may constitute useful plant material for genetic breeding .