Written Paper

Effect of duration of priming on different traits of two maize cultivars (Zea mays L.) under deficit irrigation conditions  [2017]

Arefi, Yaeghob Farajzadeh Memari Tabrizi, Elnaz

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Introduction Water stress is the most important non-disease stress with adverse effects on plant growth and yield. The inadequate emergence of seedlings and inappropriate establishment of the factors limiting the growth and yield of plants, especially in areas with low rainfall. Successful deployment of seedlings increases the competitiveness of crops against weeds and increases plant resistance to dehydration and pests. On the other hand, by expediting the treatment, provided enough time to plant a second plant. Studies have shown that priming improves germination, reduces the time of emergence of seedlings, and results in improved plant deployment. Selection of suitable cultivar and seed priming modify the adverse effects of moisture stress on plant growth and development. The aim of this study was to investigate the effect of different levels of irrigation and duration of priming on growth and yield and corn cultivars. Materials and methods This research was carried out in 1394 in laboratory and field conditions. In laboratory conditions, factorial experiment was conducted based on a completely randomized design. The first factor consisted of three levels of polyethylene glycol application (irrigation with distilled water, irrigation with polyethylene glycol solution (distilled water, concentration of 12% by volume and irrigation with polyethylene glycol solution with concentration of 25% by weight), the second factor of priming time (zero, 8, 12 and 24
hours), the third factor consisted of two cultivars of maize (704 and 604). In this study, the effect of simultaneous priming (zero (no priming), 8, 16 and 24 hours) in the field conditions, and two varieties Corn (706 and 604) under three moisture conditions (irrigation after 70, 110 and 150 mm evaporation from class A evaporation pan) was investigated. The experiment was carried out in three replicates and split factorial based on randomized complete block design. The application of irrigation levels after plant deployment of corn in the 6-8 leaf stage in the field began. Priming seeds were done before planting.FindingsIn laboratory conditions, in 704, 25% m/v of polyethylene glycol treatments decreased germination percentage by 3.8%. The highest seedling dry weight was obtained in two treatments of distilled water, 16 hours priming and 604, and 12% by weight of polyethylene glycol, 8 hours priming and 704 with a value of 1.06. In this study, in distilled water, priming had no significant effect on dry weight of seedlings of corn, but in 25% of treatment weight of polyethylene glycol, priming treatments of 16 and 24 hours reduced to 86 and 80% in 704 and priming treatments 8, 16 and 24 Hours at 604 significantly increased 52, 52 and 72% in seedling dry weight. In this study, the highest germination rate coefficient was obtained in distilled water and 8 hours priming with 0.85 per day, and the lowest in treatment of 25% by weight of polyethylene glycol day and non-priming with 0.4%. The treatment of 25% polyethylene glycol in non-priming and 8 hours priming treatments caused a significant decrease of 0.36 and 0.20 per day in germination rate, but did not affect germination rate in priming treatments of 16 and 24 hours. There was no significant difference in grain yield between cultivars in terms of field conditions. Moisture stress had a significant effect on yield loss, so that in case of non-priming, irrigation after 150 mm of evaporation caused a decrease of evaporation of 52% in grain yield compared with irrigation after 70 mm evaporation. However, priming of corn seeds over a period of more than 16 hours prevented this decrease in water-induced function. In the absence of priming, priming for 8 and 16 hours, irrigation treatment after 110 mm evaporation from the pan had no effect on grain yield. Dehydrated weight, ear weight, and shoot dry weight, leaf chlorophyll content, leaf area and plant height decreased 20.7, 21.9, 14.9, 42.9 and 10.6%, respectively. Priming had a significant positive effect on traits and 8 hours priming increased 19.9%, 15.3% and 19.2%, leaf area, shoot weight and seed number, but depending on the treatment time, the effect of priming was different. Conclusion considering the results of the effect of priming against water deficit, there was no significant effect on seed yield under full irrigation conditions. There were no differences between the cultivars in most of the traits. In general, it seems that in the studied traits under full irrigation conditions, the lower periods of pre-treatment had a more positive effect, while in dehydration conditions, the effect of longer priming periods was better. The total priming of 8 and 16 hours was the most effective period of priming for grain yield.