Journal of Crop Production and Processing

fa ارزیابی عملکرد کمی و کیفی ارقام تجاری نیشکر (.Saccharum officinarum L) تحت تاریخ‌های مختلف برداشت در منطقه اهواز Evaluation of Quantitative and Qualitative Performance of Commercial Sugarcane Cultivars under Different Harvest Dates in Ahvaz Conditions عمومى General پژوهشي Research <div style="text-align: justify;">زمان برداشت به‌عنوان یکی از عوامل کلیدی در تعیین کمیت و کیفیت محصول نیشکر شناخته می‌شود؛ به‌طوری که برداشت زود&rlm;هنگام می‌تواند منجر به کاهش قند قابل استحصال و برداشت دیر هنگام ممکن است کیفیت محصول را کاهش داده و خطر خوابیدگی و نیز شیوع بیماری‌های ساقه را افزایش دهد. این پژوهش با هدف بررسی اثر تاریخ‌های مختلف برداشت بر صفات کمی و کیفی دو رقم تجاری نیشکر CP69-1062 و CP48-103، در دو کشت و صنعت امام خمینی (ره) و کشت و صنعت امیرکبیر به ترتیب، واقع در مناطق شمال و جنوب اهواز طی سال زراعی ۱۴۰۴–۱۴۰۳ انجام شد. آزمایش به صورت کرت‌های خرد شده در قالب طرح بلوک‌های کامل تصادفی با سه تکرار اجرا شد. ارقام به عنوان کرت اصلی و چهار تاریخ برداشت (اوایل ماه های دی، بهمن، اسفند و فروردین) به‌عنوان کرت فرعی بررسی شدند. صفات کمی شامل ارتفاع ساقه ، قطر ساقه، وزن تک ‌ساقه، تعداد میان&rlm;گره و عملکرد شکر و صفات کیفی شامل درصد ساکارز (پل)، بریکس، درجه خلوص شربت و شکر قابل استحصال اندازه‌گیری شد. نتایج تجزیه مرکب نشان داد اثر متقابل رقم در تاریخ برداشت بر تمامی صفات به جز ارتفاع ساقه و تعداد میان‌گره معنی‌دار شد. رقم میان‌رس CP69-1062 در تاریخ برداشت بهمن بالاترین مقادیر بریکس (23/4 درصد)، درجه خلوص شربت (91/4 درصد)، پل (22/6 درصد) و عملکرد شکر (12/8 تن در هکتار) را به‌ دست آورد. رقم CP48-103 (میان‌رس متمایل به دیررس) بیشترین مقادیر را در برداشت اسفند (بریکس21/9 درصد، درجه خلوص شربت 92/4 درصد، پل 21/74 درصد و عملکرد شکر12/82 تن در هکتار) داشت، اما در سایر تاریخ‌ها افت عملکرد و کیفیت نشان داد. شاخص‌های فیزیولوژیک، به ویژه دوام سطح برگ، سرعت رشد گیاه و سرعت جذب خالص، با اغلب صفات کمی و کیفی همبستگی مثبت و معنی‌داری داشتند. بر اساس نتایج به دست آمده، با توجه به دوره رسیدگی و پاسخ&rlm;های فیزیولوژک هر رقم، مناسب&rlm;ترین نقطه تعادلی عملکرد کمی و کیفی رقم  CP69-1062در تاریخ برداشت هفته اول بهمن و رقم CP48-103 در تاریخ برداشت هفته اول اسفند حاصل شد. انتخاب این تاریخ‌ها با توجه به کارایی فتوسنتزی بالاتر و ویژگی‌های رسیدگی مطلوب هر رقم، موجب دستیابی به حداکثر عملکرد و کیفیت شکر و در نتیجه موجب افزایش بهره‌وری کارخانه قند می‌شود.</div> <div style="text-align: justify;">Extended Abstract: Introduction: Sugarcane (Saccharum officinarum L.) was recognized as one of the most important agro‑industrial crops in tropical regions, providing the main source of sucrose as well as raw materials for ethanol, animal feed, and diverse food and chemical industries. In Iran, the subtropical climate of Ahvaz Province in southwest of Iran has provided an appropriate environment for the stability and expansion of sugarcane production, and this province alone supplies most of the national sugar demands. Improving productivity and maintaining sucrose quality requires a precise understanding of the physiology and growth behavior of commercial cultivars under field conditions. Among management factors, harvest date is known as a key determinant affecting both the quantitative and qualitative traits of the crop by altering the stage of stalk maturity and sucrose accumulation. In many previous field investigations, the physiological growth indices of sugarcane had not been measured with sufficient accuracy, and this lack of data had limited comprehensive understanding of the growth pattern and its relationship with yield and quality attributes. This scientific gap has highlighted the need to examine the relationships among growth indices and sugar yield at the farm level. Therefore, the present study was conducted to evaluate the effects of four harvest dates (early December, early January, early February, and early March) across two contrasting locations (Amir Kabir and Imam Khomeini Sugarcane Complexes) on the quantitative and qualitative characteristics of two commercial sugarcane cultivars, CP69‑1062 and CP48‑103. The study aimed to clarify the physiological behavior of each cultivar and identify the major determinants contributing to enhanced sugar yield and quality under different climatic conditions in Khuzestan, southwest of Iran. Materials and Methods: This study was conducted to investigate the effect of different harvest dates on quantitative, qualitative, and physiological traits of two commercial sugarcane cultivars (CP48‑103 and CP69‑1062) during the 2024–2025 growing season in Khuzestan Province. Experiments were carried out at two locations: Amir Kabir Agro-Industry in southern Ahvaz and Imam Khomeini Agro-Industry in northern Ahvaz. A split-plot arrangement based on a randomized complete block design with three replications was used. Cultivars were assigned to the main plots, and four harvest dates (early December, early January, early February, and early March) were considered as subplots. Physiological traits including leaf area duration (LAD), leaf area index (LAI), crop growth rate (CGR), and net assimilation rate (NAR) were measured at seven sampling intervals at 15‑day steps from mid‑August to mid‑November. Morphological traits of talk including height, diameter, individual stalk weight, and internode number, as well as qualitative traits including sucrose, brix, purity, and recoverable sugar (RS), were measured in the quality control laboratories of Amir Kabir and Imam Khomeini Agro‑industries. Recoverable and final yield were calculated based on standard sugarcane industry formulas. Statistical analyses were performed using SAS software version 9.4. Mean comparisons were performed using Duncan’s test at 5% probability level after confirming the homogeneity of error variance using Bartlett’s test. Results and Discussion: Results showed that cultivar and harvest date had significant effects on most quantitative and qualitative traits of sugarcane, whereas only internode number showed no significant difference and exhibited a consistent pattern across all harvest dates. The mid‑maturing cultivar CP69‑1062 showed earlier sucrose accumulation and reached its maximum quality indices (including 23.40% brix, 12.80% recoverable sugar, 91.38% purity, and 22.64% pol) in February. In contrast, CP48‑103 exhibited a slower maturity pattern and attained its highest quality values (21.90% brix, 12.82% recoverable sugar, 92.37% purity, and 21.74% pol) in March, indicating different maturity behavior between cultivars. Stalk morphology traits such as stem height, stem diameter, and single‑stem weight increased with delayed harvest dates and reached their highest values in April. The greatest stem weight (865 g) and stem diameter (24.17 cm) were observed for CP69‑1062 in April, whereas CP48‑103 showed lower but gradually increasing growth. However, the number of internodes was not significantly affected by harvest date and remained relatively constant. Correlation analysis revealed that physiological traits played a major role in determining sugar quality and yield. Recoverable sugar showed strong positive correlations with NAR (r = 0.92**), LAD (r = 0.73**), and CGR (r = 0.75**). Sugar yield also had significant positive correlations with LAD (r = 0.78**), NAR (r = 0.93**), and CGR (r = 0.71**), highlighting the importance of sustained photosynthetic activity and canopy longevity in improving sugar accumulation and final yield. Conclusions: The results of this study demonstrated that harvest date and varietal characteristics significantly affected both qualitative and quantitative traits of sugarcane, and the interaction between these two factors determined the variation pattern of several physiological and agronomic indices. The cultivar CP69‑1062 harvested in February exhibited superior quality attributes, including higher values of Brix, juice purity, Pol, and recoverable sugar, together with higher photosynthetic efficiency and more stable performance under varying field conditions. In contrast, cultivar CP48‑103 expressed its highest juice quality in March. The maximum values of stalk morphology traits, including stalk height, stalk diameter, and single stalk weight, for both cultivars were observed in April, whereas the highest sugar yield was obtained in March. Correlation analysis revealed that among the physiological indices (NAR, LAI, CGR, and LAD), LAI had the weakest relationship with the improvement of both quantitative and qualitative traits, indicating that it was not a reliable predictor of sugar yield and quality compared with the other indices. Considering that early harvesting may reduce yield and juice quality, whereas delayed harvesting may increase lodging risk, stalk losses, and reduce quantitative yield, the most suitable harvesting period to achieve desirable yield and quality for the two commercial cultivars studied is from February to March. Overall, cultivar CP69‑1062 is recommended as the more stable and efficient cultivar for sugar production in Ahvaz, southwest of Iran.</div> شاخص‌های فیزیولوژیک, سرعت جذب خالص, درجه خلوص شربت, شکر قابل استحصال Physiological indices, Net assimilation rate, Juice purity, Recoverable sugar 37 56 http://jcpp.iut.ac.ir/browse.php?a_code=A-10-3880-2&slc_lang=fa&sid=1 Habibolah Roshanfekr حبیب اله روشنفکر h.roshanfekr@scu.ac.ir Yes Department of Plant Production and Genetics, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran. گروه مهندسی تولید و ژنتیک گیاهی، دانشکده کشاورزی، دانشگاه شهید چمران اهواز، اهواز، ایران. Alireza Azizi علیرضا عزیزی alireza.andika@yahoo.com No Department of Plant Production and Genetics, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran. گروه مهندسی تولید و ژنتیک گیاهی، دانشکده کشاورزی، دانشگاه شهید چمران اهواز، اهواز، ایران. Payman Hassibi پیمان حسیبی p.hassibi@scu.ac.ir No . Department of Plant Production and Genetics, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran. گروه مهندسی تولید و ژنتیک گیاهی، دانشکده کشاورزی، دانشگاه شهید چمران اهواز، اهواز، ایران. Hossein Norouzi حسین نوروزی HossienNoroozi@yahoo.com No Agronomy Research Group, Sugarcane Research and Education Development Institute Khuzestan, Ahvaz, Iran. گروه تحقیقات به زراعی موسسه تحقیقات و آموزش توسعه نیشکر خوزستان، اهواز، ایران.