بررسی اثر سطوح کودهای اوره و دامی و تلقیح بذر با باکتری pantoea agglomeransبر رنگیزه‌های گیاهی، ویژگی‌های رویشی، کیفی و کمی کاهو (lactuca sativa)

به منظور بررسی اثر سطوح کودهای اوره و دامی و تلقیح بذر با باکتری p. agglomerans آزمایش فاکتوریل در قالب طرح بلوک کامل تصادفی در گلخانه دانشکده کشاورزی و منابع طبیعی دانشگاه هرمزگان در سه تکرار انجام شد. عوامل آزمایش شامل استفاده از باکتری p. agglomerans به عنوان عامل اول (در دو سطح تلقیح یا عدم تلقیح بذر کاهو) و عامل دوم شامل سطوح کودی اوره (50 و 100 کیلوگرم نیتروژن خالص در هکتار) و کود دامی (50 و 100 کیلوگرم نیتروژن خالص در هکتار) و شاهد بودند. نتایج جدول تجزیه واریانس نشان داد که کود بر تمام صفات کاهو اثر معنی‌دار داشت. همچنین اثر تلقیح بذر کاهو با باکتری بر صفات کلروفیل a و b و فلاونوئید برگ معنی‌دار نشد در حالی‌که بر سایر صفات ارزیابی شده معنی‌دار شد. اثر متقابل کود و باکتری بر صفات کلروفیل b، سطح برگ و شاخص سطح برگ نهایی و تعداد برگ در بوته معنی‌دار نشد، اما بر سایر صفات شد. نتایج اثر اصلی نشان داد که کاربرد 100 کیلوگرم نیتروژن خالص به‌صورت اوره باعث افزایش معنی‌دار تعداد و شاخص سطح برگ نهایی، کلروفیل a، کل و کارتنوئید کاهو در مقایسه با شرایط عدم کاربرد کود شد که با کاربرد 100 کیلوگرم  نیتروژن خالص به‌صورت کود دامی در هکتار تفاوت معنی‌دار نداشتند. اما بیشترین میزان tss برگ در حضور 100 کیلوگرم  نیتروژن خالص به‌صورت کود دامی بدست آمد. نتایج اثر اصلی نشان داد که تلقیح بذر باعث افزایش معنی‌دار تعداد برگ، سطح و شاخص سطح برگ نهایی بوته به ترتیب به میزان 12.54، 26.9 و 26.5 درصد در مقایسه با شرایط بدون تلقیح شد. بیشترین میزان کلروفیل a  و کارتنوئید با کاربرد 100 کیلوگرم  نیتروژن خالص به‌صورت کود دامی و تلقیح بذر با باکتری بدست آمد. تلقیح بذر و کاربرد کود باعث بهبود ویژگی‌های کیفی و کمی برگ کاهو شد. تلقیح بذر باعث افزایش فنل و فلاونوئید و کاهش نیترات برگ در هر سطح کودی شد. بیشترین عملکرد هد و اقتصادی، با کاربرد 100 کیلوگرم  نیتروژن خالص به‌صورت کود اوره و تلقیح بذر بدست آمد. در مجموع نتایج این تحقیق نشان داد که تلقیح بذر کاهو از طریق بهبود ویژگی‌های رویشی موجب افزایش عملکرد هد و اقتصادی کاهو شد. با توجه به نتایج پژوهش حاضر، کاربرد کود دامی همراه با تلقیح بذر با باکتری p. agglomerans جهت بهبود ویژگی‌های کیفی و کمی کاهو توصیه می‌شود.

effect of fertilizer and seed inoculation with pantoea agglomerans on pigments, vegetative, qualitative, and quantitative characteristics of lettuce (lactuca sativa)

extended abstract  introduction: using chemical fertilizers is considered a common method to improve soil fertility. in recent decades, the increase in crop production has depended on chemical fertilizers, especially nitrogen fertilizers. this issue has increased environmental pollution and damage to agricultural ecosystems in intensive agricultural systems. so, the continuous use of chemical fertilizers has destroyed the soil structure and reduced the potential yield of crops. to coordinate with sustainable agriculture’s goals and deal with the adverse effects caused by the use of chemical fertilizers, biofertilizers have been proposed as an alternative to chemical fertilizers. various studies have shown that the presence of agglomerans bacteria in the rhizosphere increases the yield of various crops by improving the absorption of nutrients including nitrogen. therefore, this experiment was carried out to evaluate the use of fertilizer p agglomerans as biofertilizers in lettuce production.materials and methods: to investigate the effect of fertilizer (urea and manure) on lettuce under the seed inoculation with p. agglomerans condition, a factorial experiment was conducted in the form of a randomized complete block design in the greenhouse faculty of agriculture and natural resources of the university of hormozgan, in three replications. the experimental factors include inoculation or non inoculation of lettuce seeds with p. agglomerans bacteria as the first factor and fertilizer levels including 50 and 100 kg n ha 1 as urea fertilizer (108.7 and 217.4 kg ha 1) and manure (5000 and 10000 kg ha 1) as second factors. the evaluated traits included leaf pigment content (chlorophyll and carotenoids), vegetative characteristics (final leaf area, final leaf area index, final head height, and diameter), qualitative characteristics (total phenol, flavonoid, and leaf nitrate content), and yield (head and economic yields and percentage of yield reduction).results and discussion: the results of the main effect showed that the application of 100 kg n ha 1 as urea caused a significant increase in leaf number and final leaf area index, chlorophyll a, total, and carotenoid content compared to non fertilizer control, which did not have a significant difference with the application of 100 kg n ha 1 of manure. however, the highest level of leaf tss was obtained in the presence of 100 kg n ha 1 of manure. seed inoculation caused a significant increase in the leaf number per plant, the final leaf area, and the final leaf area index by 12.54, 26.9, and 26.5%, respectively. the highest chlorophyll and carotenoid contents were obtained by applying 100 kg n ha 1 of manure and seed inoculation. seed inoculation increased the head height and diameter compared to no inoculation, although this increase was not significant. also, seed inoculation increased leaf phenol and flavonoid content at each level of fertilizer, which was significant for two levels of manure. with the application of fertilizer, the total leaf phenol and flavonoid content increased significantly compared to the non fertilizer control. in the condition of no seed inoculation, the application of urea and animal manure fertilizer at the rate of 100 kg n ha 1 increases the total phenol by 40.5 and 34.8 percent, respectively, and the flavonoid increases by 62.4 and 34.7 percent, respectively, compared to the non fertilizer control. leaf nitrate, as a qualitative index that is directly related to human health, was affected by experimental treatments. fertilizer application caused a significant increase in this index, and the largest increase was observed with urea application. seed inoculation with agglomerans reduced lettuce leaf nitrate at all fertilizer levels. but this reduction was significant only for animal manure. the results showed that in the conditions of non seed inoculation and seed inoculation with p. agglomerans, the application of 100 kg n ha 1 as urea increased leaf nitrate by 69.6% and 69.3%, respectively, compared to the control, while these values ​​for the highest level of animal manure were obtained by 37.3% and 22.1% respectively. these results showed that seed inoculation with p. agglomerans increased economical yield in non fertilizer application, application of 50 and 100 kg n ha 1 of urea, application of 50 and 100 kg n ha 1 of manure, by 18.0, 32.5, 15.4, 27.0 and 15.4% respectively, compared to non seed inoculation. the application of fertilizer and seed inoculation caused a significant decrease in the percentage of yield reduction from 15.5 to 42.0%.conclusion: in this study, seed inoculation with agglomerans increased leaf chlorophyll content, vegetative and yield indices as well as quality characteristics of lettuce leaves. leaf nitrate increased with fertilizer application, but seed inoculation with p. agglomerans caused a significant decrease in this quality index. overall, the results of this research showed that the inoculation of lettuce seeds in the presence of urea and animal manure increased the economical yield and reduced the percentage of yield reduction through improving vegetative characteristics and increasing leaf chlorophyll.