تاثير كم آبي و ميكوريزا بر عملكرد دانه، خصوصيات زايشي و فيزيولوژيكي ارقام ذرت

Effects of water deficit and mycorrhizae on grain yield, reproductive and physiological traits of corn hybrids

كاربرد ميكوريز و انتخاب رقم مناسب مي تواند از جمله مديريت هاي ساده در برابر عوامل تنش زا مانند كم آبي باشد. اين مطالعه با هدف بررسي تاثير سطوح آبياري (آبياري پس از 70، 110 و 150 ميلي متر تبخير از تشتك)، تيمار ميكوريز (كاربرد و عدم كاربرد ميكوريز) و رقم (704 و 640) بر رشد و عملكرد ذرت انجام شد. آزمايش در سه تكرار و به صورت اسپيلت پلات فاكتوريل بر پايه طرح بلوك هاي كامل تصادفي در سال 1394 در دانشگاه آزاد اسلامي واحد ملكان اجرا شد. بر اساس نتايج به دست آمده، واكنش ارقام به كم آبي متفاوت بود. در تيمار آبياري پس از 70 ميلي متر تبخير از تشتك تبخير در رقم 704 بيشترين عملكرد دانه به دست آمد. در رقم 704 هر دو تيمار آبياري پس از 110 ميلي متر تبخير از تشتك تبخير و آبياري پس از 150 ميلي متر تبخير از تشتك تبخير به ترتيب باعث كاهش 19 و 50.6 درصدي عملكرد دانه در واحد سطح شد، ولي در رقم 640 كه در شرايط آبياري كامل نيز از عملكرد كمتري نسبت به 704 برخوردار بود، كم آبي تاثيري بر عملكرد دانه در واحد سطح نداشت. تيمار ميكوريز نيز افزايش 25.2 درصدي را در عملكرد دانه ذرت باعث شد. كم آبي بر كلروفيل a تاثيري نداشت، ولي محتواي كلروفيل b را كاهش داد، درحالي كه ميكوريز باعث افزايش كلروفيل a شد. كم آبي و ميكوريز بر محتواي كاتالاز و پراكسيداز نيز افزود. در كل به دليل عدم وجود اختلاف معني دار بين ارقام در شرايط كم آبي شديد و بالا بودن عملكرد رقم 704، كاشت رقم 704 و اعمال تيمار ميكوريز جهت كشت در منطقه پيشنهاد مي شود.

Increasing crop production to ensure future food security while reducing environmental pressure on agro-ecosystems requires improved water and nutrient use efficiency. the arid and semiarid regions of the world lack of sufficient water supply is the major problem for corn cultivation and is a restriction for its production, so studies on the growth limitation and germination of corn seeds under drought conditions seems very necessary. The effects of drought on plant growth depend on several factors such as plant genetic resistance, stage of growth and duration of plant expose to drought. The AMF are playing a vital role in sustainable agriculture because they enhance plant water relations, which improve the drought resistance of host plants. It is important to increase our understanding of AM fungal and maize genotype interactions and water condition on the symbiosis, and on the physiology and nutritional status of maize plants. Thus Mycorrhizae application and choosing suitable cultivar are of simple managements in decreasing drought effect. This investigation had done in order to investigate effect of irrigation regimes (irrigation after 70, 110 and 150 mm evaporaation from evaporate basin), Mycorrhizae (non application and application of Mycorrhizae) and cultivar (704 and 640) on growth and yield of maize. A split factorial experiment based on randomized complete block design with three replications was conducted during growing season of 2015 at Islamic Azad University, Malekan Branch, Plots were then furrow irrigated in the mornings every week. Each block was including 12 plots. The size of each plot was 3.5m×4m, and there was in each plot, 5 rows with a distance of 75 cm, and the length of 4 m. The distance between plots was selected 150 cm, and the distance between blocks was selected 3 m. By mid August an area of 2.5 m from 3 line of plot area was separately harvested and traits were evaluated. MSTAT-C and EXCEL were used to analyze data and draw graphs, respectively. Based on results of this investigation, response of cultivars to drought were different. In irrigation after 70 mm evaporaation from evaporate basin in 704 cultivar highest grain yield observed. In cultivar 704 both irrigation after 110 mm evaporaation from evaporate basin and irrigation after 150 mm evaporaation from evaporate basin decreased grain yield by 19 and 50.6 % in grain yield, but in 640 cultivar that had higher grain yield in control than 704, drought did not had significant effect on grain yield. Mycorrhizae also increased grain yield by 25.2 %. All three factor of drought, Mycorrhizae and cultivar caused changes by changing both yield component of grain number and 100 grain weight. It seems drought caused a decrease in grain number by decreasing number of total floret and increasing unfertile floret number, but Mycorrhizae had opposite effect that this decrease in floret number can caused by gap increase between tasseling and silk emergence. Drought did not had effect on chlorophyll a, but it decreased chlorophyll b, but Mycorrhizae caused an increase in chlorophyll b. Drought and Mycorrhizae increased catalase and Peroxidase content. We then suggest potential areas for future research related to (a) the adoption of cropping practices promoting AM colonization and survival; (b) the further understanding of AM effects on maize morpho-physiology; and (c) the creation of AM-colonized, drought-tolerant maize cultivars through conventional breeding as well as molecular and genomic techniques.