Emir. J. Food Agric. 2013. 25 (2): 109-116 doi: 10.9755/ejfa.v25i2.7151 http://www.ejfa.info/ 109 PLANT SCIENCE Agronomic and physiological responses of pearl millet ecotype (Pennisetum glaucum (L.) R. Br.) to saline irrigation Leila Radhouane * National Research Institute for Agricultural of Tunisia, Avenue Hédi Karray, 2049 Ariana, Tunisie Abstract The objective of this study was to identify morphological and physiological traits for salinity tolerance in Tunisian autochthonous ZZ pearl millet ecotype (Pennisetum glaucum (L.) R. Br) under local conditions. ZZ ecotype was cultivated under different levels of salinity and growth parameters, water relations and mineral content were measured. Results showed that ZZ pearl millet ecotype was unable to store the large amounts of salt in the leaves, while maintaining high leaf water content and without a grave consequent on panicle yield. This ecotype is fitted for a selective sodium sequestration in the vacuole. Key words: pearl millet, Saline water, Morphological trait, Physiological trait, Leaf water content, Ion content Introduction Pearl millet [Pennisetum glaucum (L.) R. Br] is one of the major cereal crops of the semi-arid regions of Africa and Asia and it is certainly the mainstay for millions of people in the Sahel. It’s grown as grain and fodder crop (Blummel et al., 2003). In Tunisia, pear millet is not the staple food of rural populations as in the other countries of Africa. Nevertheless, it occupies a very important part of surfaces every year in the centre and in the South of the country. In 2003, local production was about 19150 metric tonnes of pearl millet grains principally produced in Kairouan (50%), Medenine (26%), Nabeul (15.6%) and Mahdia (3.4%) regions (FAO, 2003). All pearl millet production is used for a variety of food products. Pearl millet is a summer irrigated crop. However, Tunisia, as in the majority of the arid areas, is classified among the countries threatened by dryness and salinity (Qadir et al., 2006). In fact, water availability is below the threshold of 1000 m 3 /person/year (Paranychianakis and Chartzoulakis, 2005). In order to overcome water scarcity, many countries have adopted the use of marginal water for irrigation (Oron et al., 2002). However, the salinity of those water sources typically exceeds the limit tolerated by conventional crop plants which are for the majority sensitive glycophytes (Hu et al., 2005). Plants, whether glycophyte or halophyte, cannot tolerate large amounts of salt in the cytoplasm, so, they develop a plethora of mechanisms to cope with salt stress and to facilitate their metabolic functions (Zhu, 2003). In fact, salt stress affects all the major processes such as growth, photosynthesis, protein synthesis, and energy and lipid metabolism (Parida and Das, 2005). However, some moderately or highly salt tolerant plants can survive in salty environments. These species are able to avoid ion toxicity and maintain water uptake in the presence of high salt concentrations (Munns, 2002). Pearl millet (Pennisetum glaucum (L.) R. Br.) is rated to be fairly tolerant to salinity (Krishnamurthy et al., 2007). Moreover, availability of high levels of tolerance in other species of Pennisetum (Muscolo et al. 2003) and within the P. glaucum (Krishnamurthy et al., 2007) offers a scope for understanding the traits related to tolerance and to integrate these tolerant crop species/genotypes into appropriate management programs to improve the productivity of the saline soils (Baisakh et al., 2008). Identifying autochthonous ecotypes growing under local agricultural conditions with significant levels of beneficial factors may promote the value- added cultivation and enhancing the agricultural economy. The effects of salt stress on plant growth and physiology have been well documented in other Received 23 January 2012; Revised 01 April 2012; Accepted 06 May 2012; Published Online 28 November 2012 *Corresponding Author Leila Radhouane National Research Institute for Agricultural of Tunisia, Avenue Hédi Karray, 2049 Ariana, Tunisie Email: radhouane.leila@iresa.agrinet.tn