Germination and Growth of Alfalfa (Medicago sativa L.) Irrigated with Different Dilutions of Red Sea Water

Abstract

Two experiments were conducted at the Faculty of Agriculture University of Khartoum to evaluate germination capacity and growth of four cultivars of alfalfa (Medicago sativa L.), irrigated with mixtures of Red Sea water and fresh water. The cultivars were Higazee, Yazd, Siriver and Cuf101. Plants were grown in loamy sand culture in plastic pot. The plants were irrigated with mixture water of EC 0.4, 3.4, 5.5, 9.8 and 16.5 and 0.4, 2.5, 3.4, 4.6 and 5.5dSm-1 for the first experiment and second experiment respectively. Measurements made in the study included plant height, leaf number and root/ shoot ratio. The threshold value at which plants germinated was 3.4 dSm-1 (1:15 Seawater: Freshwater) for all cultivars. Water with EC 3.4dSm-1 resulted in an acceptable germination level for all cultivars. A mixture with EC above that would either result in germination percentage around 50% or may lead to a complete failure of germination. Generally, increasing the level of salinity of irrigation water significantly decreased the rate of growth. Significant genotypic differences in plant height, leaf number and root/ shoot ratio were found among the cultivars under different saline water treatments. Cultivar Yazd appeared to be the most salt tolerant in terms of plant height, number of leaves and root/ XII shoot ratio. It was generally observed that Cuf101 and Siriver cultivars are slow growers even under fresh water. Growth was severely checked by water of EC 2.5dSm-1 indicating a very low tolerance of alfalfa to saline irrigation water.