تاثیر برخی از عناصر پرمصرف بر فعالیت نماتد ریشه‌گرهی، meloidogyne javanica در بادمجان (solanum melongena l.)

استفاده از روش‌هایی ایمن در مهار نماتدهای ریشه‌گرهی امری اجتناب‌ناپذیر می‌باشد. در مطالعه حاضر تاثیر سطوح مختلف عناصر پرمصرف نیتروژن و فسفر بر فعالیت نماتد ریشه‌گرهی meloidogyne javanica روی بادمجان رقم دلمه‌ای در شرایط گلخانه مطالعه گردید. در این مطالعه از سطوح انتخابی صفر، 50، 100 و 200 میلی‌گرم نیتروژن و صفر، 25، 50 و 100 میلی‌گرم فسفر در کیلوگرم خاک، به ترتیب از منابع نانو‌کود‌ کلات نیتروژن و نانو‌کود‌ کلات فسفر استفاده گردید. بذر بادمجان رقم دلمه‌ای در گلدان‌های پلاستیکی حاوی دو کیلوگرم بستر کشت شامل نسبت مساوی از ماسه، خاک مزرعه و کود دامی در شرایط کنترل شده گلخانه کشت گردید. در مرحله چهار برگی مایه‌زنی نماتد با افزودن پنج تخم و لارو سن دوم نماتد در گرم خاک انجام و 10 روز پس از مایه‌زنی سطوح مختلف نیتروژن و فسفر همراه با آب آبیاری (100 میلی‌لیتر در گلدان) به گلدان‌ها اضافه گردید. آزمایش به صورت فاکتوریل در قالب طرح کاملاً تصادفی در چهار تکرار انجام شد. 60 روز پس از مایه‌زنی شاخص‌های رشدی گیاه و جمعیتی نماتد اندازه‌گیری شد. نتایج نشان داد استفاده از 100 میلی‌گرم نیتروژن و 100 میلی‌گرم فسفر در کیلوگرم خاک از منابع نانوکود ‌کلات نیتروژن و نانو‌کود‌ کلات فسفر به عنوان بهترین تیمار مورد استفاده در این آزمایش بود که علاوه بر افزایش شاخص‌های رویشی گیاه، باعث کاهش شاخص‌های جمعیتی نماتد شامل تعداد تخم، گال، کیسه تخم و فاکتور تولیدمثل به ترتیب به میزان 53، 52، 62 و 55 درصد گردید.

Effect of some Macronutrients on the Root-knot Nematode, Meloidogyne javanica Activities in Eggplant (Solanum melongena L.)

Introduction: Rootknot nematodes (Meloidogyne spp.) are among the most dangerous herbal parasites which destroy 8.8 to 14.6 percent of agricultural products annually. In vegetables, 50 to 80 percent damage caused by nematodes is normal. It is unavoidable to use safe methods for controlling rootknot nematodes. Plant parasitic nematodes can be inhibited using chemical fertilizers, which reduce the losses induced by plant parasites and increase total products. The aim of this study was to evaluate the effect of different levels of two macronutrients including nitrogen and phosphorous on the infection of M. javanica on eggplant (cv. Black Beauty) under greenhouse conditions.;Materials and Methods: In the current study, the levels of zero (N0), 50 (N1), 100 (N2), 200 (N3) mg nitrogen and zero (P0), 50 (P1), 100 (P2), 200 (P3) mg phosphorus per kg of soil were selected from nanochelated nitrogen fertilizer and nanochelated phosphorus fertilizer, respectively. The seeds of eggplant were planted in plastic pots containing 2 kg of culture media including equal amount of sand, farm soil and animal manure under greenhouse condition. The pots were irrigated daily and maintained at 27±4 °C with 16:8 h light: dark photoperiod. Four leaf stage seedlings were inoculated with five eggs and second stage juveniles of M. javanica per gram of soil, and 10 days after inoculation, different levels of fertilizers were added (100 ml per pot) to the pots through irrigation. Sixty days after inoculation, plant growth indices including shoot height, shoot fresh and dry weights and root fresh weight of the cultivated plants were recorded. Nematode population indices including number of galls and egg masses per root system, number of eggs in egg masses were also measured and finally the reproduction factor was calculated. The roots were gently washed with tap water and number of eggs in one gram of root were counted according to the procedure developed by Hussey and Barker (1973). One gram of root was stained with acid fuchsine according to the procedure developed by Byrd et al. (1983). The total number of eggs, galls and egg masses per plant root system was determined by multiplying with the root weight per plant. The final nematode population per pot was computed and finally, the reproductive factor (RF) of nematode was calculated by dividing the final nematode population by the initial nematode population (10000 eggs and second stage juveniles of M. javanica). Data on plant growth and nematode indices of the experiments were subjected to a factorial analysis of variance (Twoway ANOVA). Means were compared with least significant differences (LSDs) to identify significant difference at probability levels of P≤0.05 using SAS 9.1 software (Statistical Analysis System Institute Inc., USA) in a CRD (completely randomized design) with four replicates.;Results and Discussion: In nematode inoculated plants, the difference between shoot height and shoot fresh and dry weight of treated plants by phosphorus at the rate of 100 mg/kg soil and nontreated by nitrogen (N0P3) with control plants (N0P0) was significant. Similar results were observed in nematode inoculated plants treated by nitrogen and phosphorus at the rate of 50 and 100 mg/kg soil, respectively (N1P3), with nematode inoculated plants treated by nitrogen at the rate of 50 mg/kg soil and nontreated by phosphorus (N1P0), nematode inoculated plants treated by nitrogen and phosphorus at the rate of 100 and 100 mg/kg soil, respectively (N2P3), with nematode inoculated plants treated by nitrogen at the rate of 100 mg/kg soil and nontreated by phosphorus (N2P0) and also nematode inoculated plants treated by nitrogen and phosphorus at the rate of 200 and 100 mg/kg soil, respectively (N3P3), with nematode inoculated plants treated by nitrogen at the rate of 200 mg/kg soil and nontreated by phosphorus (N3P0) (P≤0.05). The results showed that using 100 mg nitrogen and 100 mg phosphorus per kg of soil from nanochelated nitrogen fertilizer and nanochelated phosphorus fertilizer, as the best treatment used in this experiment, decreased number of eggs, galls and egg masses per root system and reproduction factor of nematode by 53, 52, 62 and 55%, respectively. Therefore, nanochelated nitrogen and phosphorus fertilizers, as two chelated fertilizers produced using nanotechnology, can decrease the population of M. javanica in eggplant cultivated in the greenhouse. Soil drenching of these watersoluble nanofertilizers 10 days after infection of the eggplants by M. javanica can also reduce the population of nematode.