نوع مقاله : مقاله کامل علمی- پژوهشی
نویسندگان
1 مؤسسه تحقیقات اصلاح و تهیه بذر چغندرقند، سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج، ایران،
2 مؤسسه تحقیقات اصلاح و تهیه بذر چغندرقند، سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج، ایران
3 مؤسسه تحقیقات اصلاح و تهیه بذر چغندرقند، سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج، ایران.
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and Objectives: This study investigates how different harvest times affect the yield and quality of sugar beet varieties. By evaluating the performance of various varieties at different harvest times, the research aims to determine if early quantitative and qualitative assessments can accurately predict final outcomes. Confirming this hypothesis could significantly benefit breeding programs by enabling early selection, thereby speeding up the development of high-yield, high-quality sugar beet varieties.
Materials and Methods: The research involved 13 sugar beet varieties. These varieties underwent phenotypic evaluation over two years (2022 and 2023) at the Sugar Beet Research Station in Karaj Alborz, Iran. The experimental design was split-plot design based on the randomized complete block design, with four replications and five harvest dates. A combined analysis of variance was performed, treating the year effect as random and the variety and harvest date effects as fixed for white sugar yield. The mean of the main effects and their interactions were compared using Duncan's multiple range test at a 5% probability level. To assess the potential for early selection of varieties and expedite breeding, regression analysis was employed, which is a common statistical method for evaluating genotype-environment interactions. Additionally, Spearman's correlation, a non-parametric rank correlation method, was used to determine the correlation between the ranks of the varieties across different harvest dates.
Results: The analysis of variance revealed significant effects of the year, variety, harvest date, and the interactions between harvest date-year and harvest date-variety at a 1% probability level. The fifth harvest in 2022 reached an average of 11.36 t ha-1, while the first harvest in 2023 had the lowest yield, averaging 2.75 t ha-1. In terms of harvest date-variety interaction, Yalda and Hosna achieved high yields of 12.44 and 12.14 t ha-1 on the fifth and fourth harvest dates, respectively, followed by Robina and Shokoufa on the fourth and fifth dates. Regression analysis confirmed a significant linear relationship between environmental conditions and yield at the 1% probability level. This relationship indicated that as the environmental index increased, there was a corresponding increase in white sugar yield, mainly due to delayed harvest times. This pattern suggests a predictable and uniform response of white sugar yield to environmental changes. The genotype-environment interaction (linear) was also significant at the 1% probability level, indicating that although yield followed a linear trend, the slope of the regression line varied for different experimental varieties across different years and harvest dates. However, the mean square deviation from the regression line was non-significant, suggesting that the white sugar yield values of the experimental varieties closely aligned with the regression line. This implies that the response of a cultivar did not fluctuate significantly during linear changes in different years and harvest dates. In fact, despite the complexities of the genotype-environment interaction, the response of varieties to changes in different years and harvest dates remains stable around the regression line. Spearman correlation analysis supports these findings, indicating that quantitative and qualitative performance in the early stages cannot reliably predict final yield unless the harvest date is postponed until early October.
Conclusion: The study concludes that initial performance evaluations are not reliable for early selection. Delaying selection until October enhances the reliability of breeding decisions, ensuring the selection of cultivars with optimal genetic potential for high yields. This approach allows breeders to make more informed decisions, ultimately leading to the development of high-yield, high-quality sugar beet varieties. By understanding the interactions between genetic and environmental factors, breeders can improve the effectiveness of their strategies, thus contributing to more efficient sugar beet cultivation practices.
کلیدواژهها [English]