@article { author = {Ghanbari, F. and Sayyari, M.}, title = {Evaluation of Drought and Cold Treatments on Growth and Yield of Tomato in Field Conditions}, journal = {Journal Of Horticultural Science}, volume = {34}, number = {1}, pages = {171-183}, year = {2020}, publisher = {Ferdowsi University of Mashhad}, issn = {2008-4730}, eissn = {2423-3986}, doi = {10.22067/jhorts4.v34i1.82485}, abstract = {Introduction: Due to its low level of calorie and being as an excellent source of C and A vitamins as well as containing lycopene as a powerful antioxidant, Tomato (solanum lycopersicum, 2n=2 x=24), is extensively consumed in the world. According to the statistics presented in 2013, following China, United States, Turkey and Egypt, Iran ranked sixth in tomato production (6174182 kg per year) world tomato production. Similar to other tropical crops, tomato is sensitive to chilling stress. The chilling stress is considered as one of the environmental factors influencing growth and development of many plants including tomato. Applying different environmental conditions and cultivation techniques within transplant production can mitigate the chilling stress of seedlings. The seedling hardening is one of the simple technique being employed to physiological characters of plant, so as to induce subsequent stress resistance. This phenomenon is so-called cross tolerance and it means that exposing plants to stressful conditions can induce plant tolerance to upcoming stresses. Therefore, the objective of our study was to investigate the effect of drought hardening and chilling stress on tomato plant growth and productivity in field condition. Materials and Methods: This experiment was conducted in greenhouse and research laboratories of agricultural college of Bu Ali Sina University. First of all, the seeds of tomato cv. C.H Falat, were sown in pots filled with perlite and vermiculite (ratio 2:1) and then maintained under natural light and at 25±2°C / 18±2°C (day/night). At four-leaf full development stage, seedlings were subjected to seven-day drought stress simulated with polyethylene glycol 6000 (PEG) at three levels: control (0% PEG), moderate drought stress (10 % PEG equaling to 0.18 Mpa osmotic potential) and severe drought stress (20% PEG equaling to 0.57 Mpa osmotic potential). After employing different levels of drought stress and consequently placing them in recovery for 48 h, they were exposed to chilling stress and non-chilling stress condition. For imposing chilling stress, the seedlings were transferred into growth chamber under 3°C for 6 days and 6 h per day. After receiving chilling stress treatments, the produced seedlings, were planted in the field. Results and Discussion: In the present study, drought pretreatment reduced the effects of cold stress on fruit yield and quality. Results revealed that, the growth and yield of tomato plants were significantly increased by drought stress pretreatment in field condition. Herein, Seedlings without receiving drought pretreatment slowly grew and gained lower yield than those receiving drought. Some traits such as higher fruit size and shelf life and low number of decayed end blossom fruits were gained by drought application. The highest growth and yield rates were obtained through 10% PEG. These results indicate that drought stress at seedling stage increases the yield of tomato without harmful effects on fruit quality. The results showed that in 0% PEG treatment (control), chilling stress increased the number of days for flowering and fruiting, which indicates the growth retardation in this plant under cold stress condition. Drought pre-treatment using PEG increased the thickness of the pericarp and its post-harvest life, which may indicate the maintenance of the effects of initial stress in all stages of vegetative and reproductive growth. It has been reported that cold stress directly affects the growth potential of plants that interfere with the proper production of plants by disrupting metabolic reactions and indirectly by preventing the absorption of water by plants and oxidative stress (Hussain et al., 2018). In the present study, pre-treatment of drought reduced the destructive effects of chilling stress on fruit size. These results show that pre-treatment of drought (especially 10% PEG) had a significant effect on increasing fruit size and preventing its fruit yield reduction due to cold treatment. Similarly, Paradosi et al. (1987) reported that water stress in tomato plants increased its tolerance to cold and maintained the growth of tomato plants and its yield in cold greenhouse conditions. So far, there have been no reports of interactions between environmental stresses on fruit size, but the effects of drought stress on tomato fruit have been studied. Conclusion: In general, the results of this experiment showed that the effects of drought pre-treatment on seedling remain in the next stages of tomato growth and can have beneficial effects on growth and yield of tomato in field conditions.}, keywords = {Blossom End Rot,Chilling,Cross-tolerance,Hardening,Stress}, title_fa = {ارزیابی اثر پیش تیمار‌های خشکی و سرما بر رشد، نمو و میزان عملکرد گوجه‌فرنگی (Lycopersicun esculentum Mill.) در شرایط مزرعه}, abstract_fa = {دمای پایین منجر به آسیب­های فیزیولوژیکی به سلول­ در گیاهان حساس به سرمازدگی و خسارت محصولات گرمسیری و نیمه گرمسیری مانند گوجه فرنگی می­شود. به منظور ارزیابی اثر پیش تیمار خشکی بر تحمل به سرما نشا­های گوجه فرنگی و رشد و عملکرد بعدی آن در شرایط مزرعه، تحقیقی در دانشکده کشاورزی دانشگاه بوعلی سینا همدان در سال­ 1395 به صورت فاکتوریل در قالب طرح بلوک­های کامل تصادفی در سه تکرار انجام شد. تیمارهای آزمایشی شامل تنش خشکی در سه سطح (صفر، 10 و 20 درصد PEG) و تنش سرمایی در دو سطح (تنش و بدون تنش) بود. پس از اعمال پیش تیمار تنش خشکی، نشاها به مدت شش ساعت در شش روز متوالی در دمای سه درجه سانتی­گراد قرار گرفتند و پس از آن در مزرعه کاشته شدند. نتایج نشان داد که پیش تیمار خشکی تاثیر معنی­داری در افزایش رشد و عملکرد گوجه فرنگی در شرایط مزرعه دارد. گیاهانی که پیش تیمار نشده بودند پس از تیمار سرمایی رشد کمی در شرایط مزرعه داشتند و همچنین عملکرد آن­ها پایین­تر بود. پیش تیمار خشکی سبب افزایش اندازه میوه، افزایش عمر ماندگاری آن و کاهش تعداد میوه­های دارای پوسیدگی گلگاه شد. بالاترین رشد و عملکرد کل میوه در کاربرد 10 درصد PEG به دست آمد. به طور کلی نتایج این آزمایش نشان داد که پیش تیمار خشکی می­تواند به طور موثری برای حفاظت نشاهای گوجه فرنگی از آسیب ایجاد شده به وسیله تنش دمای پایین در مراحل اولیه رشد استفاده شود و سبب رشد و عملکرد بهتر گوجه فرنگی در شرایط مزرعه می­شود.}, keywords_fa = {پوسیدگی گلگاه,تنش,سرمازدگی,مقاوم سازی,مقاومت تقاطعی}, url = {https://jhs.um.ac.ir/article_37260.html}, eprint = {https://jhs.um.ac.ir/article_37260_286351dafcbb31bf313d6d98b50e89f1.pdf} }