بررسي واكنش عملكرد و اجزاي عملكرد سويا (Glycine max L.) به تاريخ كاشت، دما و ساعات آفتابي

Determination of yield and yield components response of soybean (Glycine max L.) to sowing date, temperature and sunshine hours

اين تحقيق به منظور بررسي اثر تاريخ كاشت، دما و ساعات آفتابي بر عملكرد و اجزاي عملكرد گياه سويا (Glycine max L.) در منطقه علي‌آباد كتول واقع در استان گلستان در سال زراعي 91-1390 به صورت پيمايشي انجام گرديد. به اين منظور در محدوده علي‌آباد كتول، مزارع مختلف سويا مورد شناسايي قرار گرفتند. به طور كلي در اين بررسي 30 مزرعه سويا از رقم كتول (D.P.X) و 30 مزرعه سويا از رقم ساري (J.K) انتخاب شدند. در اين پيمايش، تاريخ كاشت مزارع كه از عوامل مهم مديريتي تاثيرگذار بر عملكرد و اجزاي عملكرد مي باشد، ثبت گرديد. از هر مزرعه انتخابي براي تعيين صفات مورد نظر (طول دوره هاي مختلف فنولوژيكي، عملكرد و اجزاي عملكرد)، پنج قطعه در الگوي زيگزاكي شكل (?) انتخاب و در هر قطعه، صفات مورد نظر اندازه گيري شده و متوسط آن‌ها براي هر مزرعه ثبت گرديد. روابط بين تاريخ كاشت و همچنين دما و ساعات آفتابي (طي دوره شروع گل‌دهي تا شروع پر شدن دانه و دوره پر شدن دانه) كه متاثر از تاريخ كاشت مي باشند، با عملكرد، اجزاي عملكرد و طول دوره هاي فنولوژيكي (رويشي، زايشي و كل دوره رشد) از طريق آناليز رگرسيوني مورد بررسي قرار گرفت. نتايج نشان داد كه تمام صفات مربوط به اجزاي عملكرد در هر دو رقم كتول و ساري به غير از تعداد دانه در مترمربع در رقم ساري تحت تاثير تاخير در كاشت قرار گرفته و به طور معني دار كاهش يافت. بين عملكرد دانه و تاخير در كاشت از ابتداي تيرماه رابطه معني داري وجود داشت و به ترتيب 79 و 53 درصد از تغييرات را در ارقام كتول و ساري توجيه نمود. با توجه به شيب معادله رگرسيوني بين تاخير در كاشت و عملكرد دانه مشخص شد كه به ازاي هر روز تاخير در كاشت از اول تيرماه در ارقام ساري و كتول به ترتيب 4/37 و 6/50 كيلوگرم در هكتار از عملكرد دانه كاسته شد. بين تاخير در كاشت و طول دوره هاي مختلف رشد (رويشي، زايشي و كل دوره رشد) رابطه منفي و معني داري در سطح احتمال يك درصد وجود داشت. همچنين صفات مربوط به اجزاي عملكرد سويا تحت تاثير ميانگين دما و مجموع ساعات آفتابي طي دوره شروع گل‌دهي تا شروع پر شدن دانه و دوره پر شدن دانه قرار گرفته و افزايش يافت.

Introduction Soybean (Glycine max L.) is one of the major sources to produce oil. Suitable sowing date makes optimum use of climate factors such as temperature, moisture and during the day. Soybean is not easily adaptable with soil and climate change, because its flowering and ripping depends on duration of daylight. Long days delays flowering process and short days causes acceleration of plant maturity. Temperature is one of the most important effective factors on the growth of any kind of plant (Caliskan et al., 2008). Related to the radiation effect on the plant growth, excessive studies have been done in the world. One of the necessary pre-conditions to get upper yield is making necessary conditions for optimal use of radiation (Muchow et al., 1990). Awareness of the effective factors on the yield of soybean can help us to get better management of the plant. Therefore, the goal of this research was to study the effect of sowing date, temperature and sunshine hours on the length of growth period, yield and yield components of soybean. Materials and methods This research was performed to study the effect of sowing date, temperature, and sunshine hours on yield and yield components of soybean in the area of Aliabad-Katoul in Golestan province, during 2011-2012 cropping year. In this order, different soybean fields with different sowing date had been remarked in vast area of soybean fields of Aliabad-Katoul area. In this study 30 soybean fields with Katoul (D.P.X) cultivar and 30 soybean fields with Sari (J.K) cultivar werte chosen. To assess the study traits (the length of different phenological periods, yield, and yield components) into each of field, 5 plots in zigzag pattern (?) had been chosen and in each plot, the study traits had been measured and the average of them was recorded for each field. The important soybean growth stages, including the start of flowering (R1), the start of pods of the plants (R3), the start of seed formation (R5), the start of physiological ripping (R7) and complete ripping (R8) was recorded (Fehr & Caviness, 1980). Results and discussion In this study, phenological developments during growing period were influenced by the sowing date. There was a negative linear correlation between delaying of sowing date and growth duration as the 86% and 90% of the variation in the Katoul and Sari cultivars justified, respectively. Delaying of sowing date of both cultivars, reduced the yield. This negative significant linear relation explained 79% and 53% of changes in Katoul and Sari cultivars, respectively. The slope of the regression equation indicated that delaying of sowing date (days from 20th June) reduced seed yield in Katoul and Sari cultivars equal to 50.6 kg.ha-1 and 37.4 kg.ha-1 per day, respectively. The result showed that response of soybean yield components to the average of temperature during flowering and grain filling in both cultivars was positive and significant, except for seed number per square meter in Sari cultivar. Between mean temperature during starting flowering to starting grain filling and soybean pod number per plant was a positive linear correlation as the 77 and 68% of the variation in the Katoul and Sari cultivars justified, respectively. In addition, in this research it was observed that there was a significant relation between the total sunshine hours during flowering and grain filling and the components of soybean yield. Conclusion The results of this study showed that sowing date had significant effect on plant traits such as seed yield. The majority of the study traits decreased due to delay of sowing date. Thus, in the study area sowing date is one of the most important effective factors on the growth and yield of soybean. Acknowledgements The authors gratefully acknowledge the financial support of Islamic Azad University, Karaj Branch.