Volume 18, Issue 2 (4-2026)
J Crop Breed 2026, 18(2): 49-59 |
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Hajiebrahimi E, Fazeli A, Ghaffari M. (2026). Analysis of Genetic Variance Components and Combining Ability in Sunflower (Helianthus annuus L.) Lines and Testers for Oil Content and Seed Yield Improvement. J Crop Breed. 18(2), 49-59. doi:10.61882/jcb.2026.1618
URL: http://jcb.sanru.ac.ir/article-1-1618-en.html
URL: http://jcb.sanru.ac.ir/article-1-1618-en.html
1- Department of Agronomy and Plant Breeding, Faculty of Agriculture, Ilam University, Ilam, Iran
2- Department of Oil Crops Research, Seed and Plant Improvement Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
2- Department of Oil Crops Research, Seed and Plant Improvement Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
Abstract: (578 Views)
Extended Abstract
Background: Sunflower (Helianthus annuus L.), as one of the most important oilseed crops worldwide, is considered an ideal candidate for cultivation in arid and semi-arid regions of Iran due to its unique characteristics, including drought tolerance, adaptability to low-fertility soils, and relatively low water requirements. Given ongoing climate change and diminishing water resources, the development of high-yielding varieties with enhanced environmental stress tolerance has become a top research priority in plant breeding programs. The evaluation of combining ability in sunflower lines and testers plays a pivotal role in identifying superior genotypes. This study was conducted to comprehensively assess both general combining ability (GCA) and specific combining ability (SCA) of sunflower lines and testers for key agronomic traits such as seed yield, oil content, and other yield-related characteristics using the line × tester analysis method. This investigation evaluated 18 different line × tester combinations, with data collected through a randomized complete block design. Our results demonstrate that certain hybrid combinations exhibit superior combining ability for both seed production and oil quality, suggesting their potential for improved performance across diverse environmental conditions. These findings provide a solid scientific foundation for future breeding initiatives aimed at developing high-yielding, stable hybrid varieties suitable for various growing conditions. Moreover, this research offers practical guidance to farmers for selecting optimal cultivars for cultivation in areas with water and soil constraints, thereby contributing to enhanced oilseed production at the national level.
Methods: This research was conducted at the research farm of the Seed and Plant Improvement Institute in Karaj, Iran (35.84 °N latitude, 50.93 °E longitude, 1321 m altitude) during two crop years (2022-2023 and 2023-2024). The study utilized nine fertility restorer lines and two cytoplasmic male sterile (CMS) lines as testers. In the second year, 18 hybrids and 11 parental lines were cultivated in a randomized complete block design with three replications, using 65 cm row spacing and 25 cm plant spacing. Measured traits included days to flowering (DTF), flowering duration (FD), days to maturity (DTM), seed filling period (SFP), plant height (PH), head diameter (HD), thousand seed weight (TSW), seeds per head (SPH), oil content (OC), seed yield (SYH), and oil yield (OY). Soil samples were collected from 0-30 cm depth before planting. Data were analyzed using the line × tester method to estimate genetic parameters, including GCA, SCA, additive variance (σ²A), and dominance variance (σ²D). All statistical analyses were conducted using the agricolae package in the R software environment.
Results: The analysis of variance results showed that the effects of lines, testers, and the line × tester interaction were significant for most traits. The line effect was significant for DTM, SFP, and TSW, while the tester effect was significant for PH and SYH. The SCA was highly significant for key traits, including DTF, SYH, and OC. Specific combinations, such as Line 6 × Tester 1, had the most positive effects on SYH and SPH. The GCA for lines and testers revealed that Line 2 and Line 8 had the most positive effects on DTF and SFP, respectively. Additive and dominance variances also showed that key traits, such as SYH and OC, were more strongly influenced by dominance effects. The SCA analysis indicated that certain specific line × tester combinations had stronger interactive effects on the traits. For example, the Line 6 × Tester 1 combination showed the most positive effect on SYH (726.2) and SPH (156.6), while the Line 1 × Tester 2 combination showed the most negative effects on these traits. These results emphasize that selecting appropriate line × tester combinations can significantly impact the improvement of crop yield and quality.
Conclusion: This study demonstrates that strategic selection of line × tester combinations plays a pivotal role in enhancing sunflower yield and quality. Line 2 (for extended growth duration) and Line 8 (for improved grain filling period) emerged as promising candidates, along with the superior-performing Line 6 × Tester 1 hybrid, for breeding programs. Conversely, the poor performance of the Line 1 × Tester 2 combination underscored the critical importance of thorough genetic compatibility assessments. Findings confirm that SCA exerts a decisive influence on key traits, such as grain yield and oil content. These results not only provide valuable guidance for parental selection and superior hybrid development but also highlight the necessity for complementary molecular studies and multi-environment trials to cultivate well-adapted, high-yielding cultivars.
Background: Sunflower (Helianthus annuus L.), as one of the most important oilseed crops worldwide, is considered an ideal candidate for cultivation in arid and semi-arid regions of Iran due to its unique characteristics, including drought tolerance, adaptability to low-fertility soils, and relatively low water requirements. Given ongoing climate change and diminishing water resources, the development of high-yielding varieties with enhanced environmental stress tolerance has become a top research priority in plant breeding programs. The evaluation of combining ability in sunflower lines and testers plays a pivotal role in identifying superior genotypes. This study was conducted to comprehensively assess both general combining ability (GCA) and specific combining ability (SCA) of sunflower lines and testers for key agronomic traits such as seed yield, oil content, and other yield-related characteristics using the line × tester analysis method. This investigation evaluated 18 different line × tester combinations, with data collected through a randomized complete block design. Our results demonstrate that certain hybrid combinations exhibit superior combining ability for both seed production and oil quality, suggesting their potential for improved performance across diverse environmental conditions. These findings provide a solid scientific foundation for future breeding initiatives aimed at developing high-yielding, stable hybrid varieties suitable for various growing conditions. Moreover, this research offers practical guidance to farmers for selecting optimal cultivars for cultivation in areas with water and soil constraints, thereby contributing to enhanced oilseed production at the national level.
Methods: This research was conducted at the research farm of the Seed and Plant Improvement Institute in Karaj, Iran (35.84 °N latitude, 50.93 °E longitude, 1321 m altitude) during two crop years (2022-2023 and 2023-2024). The study utilized nine fertility restorer lines and two cytoplasmic male sterile (CMS) lines as testers. In the second year, 18 hybrids and 11 parental lines were cultivated in a randomized complete block design with three replications, using 65 cm row spacing and 25 cm plant spacing. Measured traits included days to flowering (DTF), flowering duration (FD), days to maturity (DTM), seed filling period (SFP), plant height (PH), head diameter (HD), thousand seed weight (TSW), seeds per head (SPH), oil content (OC), seed yield (SYH), and oil yield (OY). Soil samples were collected from 0-30 cm depth before planting. Data were analyzed using the line × tester method to estimate genetic parameters, including GCA, SCA, additive variance (σ²A), and dominance variance (σ²D). All statistical analyses were conducted using the agricolae package in the R software environment.
Results: The analysis of variance results showed that the effects of lines, testers, and the line × tester interaction were significant for most traits. The line effect was significant for DTM, SFP, and TSW, while the tester effect was significant for PH and SYH. The SCA was highly significant for key traits, including DTF, SYH, and OC. Specific combinations, such as Line 6 × Tester 1, had the most positive effects on SYH and SPH. The GCA for lines and testers revealed that Line 2 and Line 8 had the most positive effects on DTF and SFP, respectively. Additive and dominance variances also showed that key traits, such as SYH and OC, were more strongly influenced by dominance effects. The SCA analysis indicated that certain specific line × tester combinations had stronger interactive effects on the traits. For example, the Line 6 × Tester 1 combination showed the most positive effect on SYH (726.2) and SPH (156.6), while the Line 1 × Tester 2 combination showed the most negative effects on these traits. These results emphasize that selecting appropriate line × tester combinations can significantly impact the improvement of crop yield and quality.
Conclusion: This study demonstrates that strategic selection of line × tester combinations plays a pivotal role in enhancing sunflower yield and quality. Line 2 (for extended growth duration) and Line 8 (for improved grain filling period) emerged as promising candidates, along with the superior-performing Line 6 × Tester 1 hybrid, for breeding programs. Conversely, the poor performance of the Line 1 × Tester 2 combination underscored the critical importance of thorough genetic compatibility assessments. Findings confirm that SCA exerts a decisive influence on key traits, such as grain yield and oil content. These results not only provide valuable guidance for parental selection and superior hybrid development but also highlight the necessity for complementary molecular studies and multi-environment trials to cultivate well-adapted, high-yielding cultivars.
Keywords: Additive Genetic Variance, Genetic Variance of Dominance, Plant breeding, Heterosis (Hybrid Vigor), Quantitative traits
Type of Study: Research |
Subject:
اصلاح نباتات، بیومتری
Received: 2025/09/10 | Accepted: 2026/01/17
Received: 2025/09/10 | Accepted: 2026/01/17
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