Document Type : Research Paper

Authors

• Roxana Seyyed Raoufi ¹
• Saeid Soufizadeh ²
• Jafar Kambouzia ³
• Eskandar Zand ⁴
• Tohid Najafi Mirak ⁵

¹ PhD candidate, Department of Agroecology, Environmental Sciences Research Institute (ESRI) of Shahid Beheshti University, Tehran, Iran.

² Assistant Professors , Department of Agroecology, Environmental Sciences Research Institute, Shahid Beheshti University, G.C., Tehran, Iran.

³ Associate Professor,, Department of Agroecology, Environmental Sciences Research Institute (ESRI) of Shahid Beheshti University, Tehran, Iran

⁴ Associate Professor, Department of Weed Research, Iranian Research Institute for Plant Protection, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran

⁵ Associate Professor, Department of Cereal Research, Seed and Plant Improvement Institute, Alborz, Iran

Abstract

Objective: This study aimed to evaluate grain yield, its components, and key morphological and physiological traits in traditional and newly developed irrigated wheat cultivars. The goal was to identify critical agronomic factors influencing wheat yield potential under optimal field conditions.
Methods: A field experiment was conducted during the 2021–2022 growing season at the Seed and Plant Improvement Institute in Alborz Province, Iran. Using a randomized complete block design (RCBD) with 29 cultivars and three replications, comprehensive assessments of morphological, physiological, and yield-related traits were carried out at flowering and physiological maturity stages. Measurements included grain yield, biological yield, harvest index, grains per spike, thousand-grain weight, leaf area index, among others. The trial was managed under optimal conditions, free from biotic and abiotic stresses, with standard agronomic practices.
Results: Significant genetic variation (p < 0.01) was observed across all traits, indicating a strong genetic influence on performance. The highest grain yield was recorded for Shiroudi (1074 g/m²), while Baharan had the lowest (572 g/m²). Cultivars such as Shiroudi, Gonbad, Navid, Pishtaz, and Chamran 2 exhibited superior biological yields. The harvest index ranged from 37% in Baharan to over 50% in Shush, Tajan, and Aflak. Stepwise regression identified harvest index, grains per spike, thousand-grain weight, and leaf area index as primary contributors to yield, explaining 56% of the variation. Cluster analysis grouped genotypes into four clusters, with Groups I and III comprising the highest-yielding cultivars suited to Alborz’s conditions. PCA revealed that the first five components accounted for 80% of total variance. Pearson correlations confirmed strong positive relationships between grain yield and traits such as spike number, seeds per spike, biological yield, and leaf area index.
Conclusion:  Traits including harvest index, grains per spike, thousand-grain weight, and leaf area index are key determinants of grain yield and should be prioritized as selection criteria in wheat breeding programs.weight, and leaf area index play a decisive role in grain yield and can be considered as selection indicators in breeding programs.

Keywords

• Morphological traits
• Multivariate analysis
• Wheat
• Yield‏ ‏and Yield components