Document Type : Research Paper - Agronomy

Authors

• Gholamhosein Eslamnia ¹
• Mohammad Reza Moradi Telavat ²
• Seyyed Ataollah Siadat ³
• Khalil Alamisaeid ²
• Ali Akbar Saneinejad ⁴

¹ PhD Student of Agronomy, Department of Plant Production and Genetics, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Ahvaz, Iran

² Associate Professor, Department of Plant Production and Genetics, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Ahvaz, Iran

³ Professor, Department of Plant Production and Genetics, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Ahvaz, Iran

⁴ Researcher, Safiabad Agricultural Research and Education and Natural Resources Center, Iran

Abstract

Introduction
Commercial corn varieties for cultivation in different regions of the world for kernel and fodder production are hybrid type varieties that are offered annually by seed production companies for planting in farmers' fields. In recent years, the area under corn cultivation in Iran has increased, indicating the importance of this crop in the country's agricultural policies. Fodder corn varieties are classified into early- maturing (less than 85 days), medium maturing (85-135 days), and late-maturing (more than 135 days) types. Optimal planting density is a key factor in maximizing yield, as it must be adjusted based on regional climatic conditions and the cultivated varieties.  Corn responds to plant density more significantly than other cereal crops due to its impact on yield components. Selecting high-yielding cultivars and applying appropriate planting densities also improve water-use efficiency. Additionally, determining the optimal planting density for maternal lines in seed production can enhance seed yield per unit area, ultimately increasing.
 Materials and Methods
This study aimed to evaluate the eco-physiological responses of different corn lines to planting density in the northern of Khuzestan. The experiment was conducted during the summers of 2018 and 2019 at the Safi-Abad-Dezful Agriculture and Natural Resources Research and Training Center. A factorial experiment was implemented using a randomized complete block design (RCBD) with three replications. The main factor was planting density at three levels (60, 85 and 110 thousand plants per hectare), while the second factor was genotype, consisting of five experimental corn lines (SD-95-11, C3-95-5, C3-95-15, C4-95-2, C4-95-3) and the control line MO17).
Results and Discussion
The highest seed yield (2115 kg ha^-1) was observed at a planting density of 110000 plants per hectare for line 103, whereas the lowest yield (1030 kg ha^-1) was recorded at a density of 60000 plants per hectare for line 119. The results showed that the density of 110000 plants per hectare was optimal for most measured traits, making it the most suitable planting density for the tested lines. Additionally, line 103 was identified as the high potential genotype, suggesting its potential use in corn breeding programs for hot and dry regions.  
 Conclusion
Previous studies indicate that optimal planting density for grain corn is approximately 80000 plants per hectare, while for fodder corn, it is around 100000 plants per hectare. However, since the experimental materials in this study were pure corn lines, which are generally smaller than hybrids, they required higher planting densities than commercial corn varieties. Determining the appropriate planting density for corn lines is particularly important for individuals and companies engaged in seed production, as pure maternal and paternal lines are used in this sector. Achieving the optimum plant density in corn lines farms can be very important for seed producer companies, because pure paternal and maternal lines are used in these farms. On the other hand, out of a total of 6 lines used, line number 103 was selected as the best line that can be used in corn breeding programs in hot and dry regions of the country.

Keywords

• Biological yield
• Kernel yield
• Seed production
• Warm and dry regions

Main Subjects

• A: Agronomy