دوماهنامه
نوع مقاله : مقالات پژوهشی
نویسندگان
1 بخش تحقیقات فنی و مهندسی کشاورزی، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی صفی آباد دزفول، سازمان تحقیقات، آموزش و ترویج کشاورزی، دزفول، ایران
2 بخش تحقیقات علوم زراعی و باغی، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی صفی آباد دزفول، سازمان تحقیقات، آموزش و ترویج کشاورزی، دزفول، ایران
3 مؤسسه تحقیقات اصلاح و تهیه نهال و بذر، سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج، ایران
کلیدواژهها
عنوان مقاله English
نویسندگان English
Introduction
Wheat is the principal crop in Iran in terms of both production and cultivated area. Enhancing its production is critically important for the economy and national food security. Assessing the water productivity of commercial wheat varieties is key to achieving more efficient water use. Previous studies have demonstrated that wheat water productivity is influenced by cultivar type and irrigation amount, with different varieties exhibiting varying grain yields under both water deficit and surplus conditions. Increasing yield and water productivity depend on several factors, most notably the selection of high-yielding, improved cultivars with lower water requirements, coupled with irrigation management strategies tailored to the characteristics of these varieties, especially in hot and arid climates.
Materials and Methods
A two-year field experiment was conducted during the 2021-2022 and 2022-2023 growing seasons at the Safiabad Agricultural and Natural Resources Research and Education Center, using a randomized complete block design with three replications. The experimental treatments consisted of five irrigation levels (25%, 50%, 75%, 100%, and 125% of crop evapotranspiration) as the horizontal factor and six bread wheat cultivars (Azadegan, Ouj, Barat, Jalal, Darion, and Mehregan) as the vertical factor.
Following land preparation, fertilization with macronutrients was applied before planting and during the vegetative growth stage, based on soil test recommendations. Sowing was performed using a Wintersteiger row planter, and irrigation was supplied via a T-tape drip irrigation system. Water was sourced from the Dez irrigation and drainage network. The designated irrigation treatments were implemented starting from the third irrigation event, with water volumes measured using volumetric water meters. Crop evapotranspiration was calculated using the evaporation pan method, and soil moisture balance was monitored by auger sampling and the gravimetric method. Weed control was achieved through appropriate herbicide applications.
Results and Discussion
In the first and second years, total evapotranspiration (ET) was 310 mm and 300 mm, while total rainfall was 145 mm and 289 mm, respectively. Accounting for effective rainfall, the irrigation treatments supplied 42, 62, 82, 102, and 122% of the crop ET in the first year, and 60, 76, 89, 103, and 117% in the second year. A combined analysis of variance revealed a significant year effect. The grain yield of the cultivars in response to ET showed maximum variations of 10% and 30% in the first and second years, respectively. Water productivity, measured as grain yield per millimeter of water consumed, ranged from 18.43 to 22.38 kg ha⁻¹ mm⁻¹. By selecting an appropriate cultivar and managing deficit irrigation, the applied water productivity and crop water productivity indices increased by 63% and 93%, respectively. The relationship between plant water supply and grain yield followed a quadratic function. Based on this model, the optimal deficit irrigation strategy was to supply 70% of wheat ET, which resulted in an acceptable grain yield reduction of approximately 15%. Across irrigation treatments in both years, the Darion, Mehregan, and Jalal cultivars exhibited higher average grain yield and crop water productivity than the mean of all cultivars. A cluster analysis was performed using R software, based on the regression coefficients of the grain yield, relative water supply, and evapotranspiration data. The cultivars were grouped into distinct clusters, and practical, cluster-specific management recommendations are provided.
Conclusion
Hot and dry climates are characterized by high variability in evaporation, precipitation patterns, and crop water requirements across different wheat growth stages. Consequently, to achieve sustainable production and enhance water productivity within the genetic potential of wheat varieties, breeding programs should target the development of cultivars capable of producing more than 24 kg of grain per hectare per millimeter of water consumed.
کلیدواژهها English
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