Effect of Water Deficit on Grain Yield and Yield Components Ispaghula (Plantago ovata Forssk.)

Drought is the major limiting factor of plant growth and productivity in many regions of the world. To determine the response of different ecotypes of ispaghula (Plantago ovata Forssk.) to drought stress, a field experiment was conducted at the Research Institute of Forests and Rangelands, Tehran, Iran in 2018. The experimental design was a split plot based on a randomized complete block design (RCBD) with three replications. The main factor included drought stress at three levels control (D1), drought stress after flowering stage with supplemental irrigation in the filling stage (D2), and post-flowering drought stress (D3). The second factor contained eight ecotypes of Plantago ovate, including Dehloran (3328), Alborz (3968), Markazi (14592), Dashtestan (21228), Hormozgan-1 (31536), Hormozgan-2 (31563), Ghaen (37496), and Sarbisheh (38917). The results showed a significant effect of drought stress and ecotypes for all traits (P<0.01). The interaction between ecotypes and drought stress was not significant for yield and yield components. Ispaghula ecotypes Production of medicinal and aromatic plants is increasing in the world, due to their association with health benefits [1]. Medicinal plants are economically important that widely are used raw and processed in traditional and modern medicine. According to World Health Organization (WHO), medicinal plants are an accessible, affordable, and culturally appropriate source of primary health care for more than 80% of developing countries [2]. Plantago is the largest genus within the Plantaginaceae family comprising approximately 275 annuals and perennial species distributed all over the world. For centuries, Plantago species have been used in folk medicine because of their diverse properties [3]. Some species are particularly valuable in the nutraceutical and pharmaceutical industries due to the mucilaginous product (psyllium) derived from the seed husk, which has been used as a functional food and dietary supplement to improve intestinal health [4]. The value of Plantago seeds is due to the quantity and quality of mucilage in the showed similar responses to drought stress. The highest grain yield with an average value of 720 kg/ha was obtained in ecotype 3328 and it was considered as the best ecotype to cope drought stress conditions. Ispaghula grain yield decreased by an average of 11.02% and 23.65% with drought stress D2 and D3 in comparison with control (D1), respectively. A significant difference between D2 and D3 were observed, so that the grain yield of D3 was 11.26% lower than D2. Regardless of the drought stress level, ecotype Dehloran (3328) produced the highest grain and was recommended for breeding improved varieties. Considering drought the ecotype Dehloran (3328) that had a good yield under normal irrigation conditions produced the least yields than other ecotypes.