Document Type : Research Paper
Assistant Professor, Department of Water Engineering. Kashmar Higher Education Institute, Kashmar, Iran
Assistant Professor, Department of Water Engineering. Kashmar Higher Education Institute, Kashmar, Iran.
Technical Expert, Agricultural Research & Natural Resources Center, Razavi Khorasan Province, Iran.
Deficit irrigation is a suitable method for obtaining the economic and acceptable yield with the minimum amount of water (Zegbe et al., 2004). Although the yield in unit area is decreased in this irrigation method, the amount of consumption water, water harvesting, delivery and distribution costs of water decreased, which results in more benefit (Yazar et al., 2009).
Partial root drying (PRD) is the modified method of deficit irrigation which some part of plant roots is irrigated and another part of them are placed in dry soil. For the first time, the concept of PRD was applied by Grimes et al. (1968) in the United States. In this method, water uptaking from the wet zoning of plant roots holds the water status in plant in a favorable condition (Davies et al., 2002), and the other part of roots placed in dry soil results in increasing abscisic acid hormone production.
The most important growth indices which are used frequently in plants include leaf area index (LAI), crop growth rate (CGR) and relative growth rate (RGR) so that plant production dry matter can be investigated using these indices (Modarresi et al., 2004). Investigation of variations of growth indices of five maize hybrids under two different irrigation regimes indicated that interrelationship between leaf area index and grain yield was significant (Nori Azhar and Ehsanzadeh, 2007).
Water scarcity is one of the most important factors that decrease the maize yield and yield reduction depending on corn cultivars and growth stages that are affected by water stresses. With regard to desirable features of leafy and commercial hybrids of maize and also different effect of stresses in different stages of vegetative and reproductive growth, the objective of this study was to investigate the effect of water stress and new deficit irrigation strategies on growth indices of two corn cultivars in Kashmar climate.