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Pulses are among the best sources of plant protein and important components of crop rotation, which in recent years, have been considered one of the major options for plant research. Seed storage is one of the important traits in legume breeding. Storage temperature, seed moisture content, and storage duration are the most important factors affecting seed quality during storage. Inappropriate storage conditions lead to deterioration and reduction of seed quality during storage, which is severely affected by the environmental conditions of storage.

This research was conducted at the Seed Technology Laboratory, Faculty of Agriculture, Yasouj University in 2014 as a three-way factorial based on the completely randomized design with 5 replications of 20 seeds. Seeds with moisture content at 5 levels (6, 10, 14, 18, and 22%) and storage temperature at 4 levels (15, 25, 35 and 45 °C) were stored for 9 months (0, 30, 60, 90, 120, 150, 180, 210, 240 and 270 days). After sampling at the end of each month, a standard seed germination test was done using the pleated paper method in a germinator at 25 °C for 10 days. Also, an electrical conductivity test of the electrolytes leaked from the seeds incubated for 24h in water at 20 ˚C was done with 4 replicates. Some germination attributes and electrical conductivity of the electrolytes leaked from the seeds were measured according to standard methods.

According to the results, interaction effects of storage temperature, seed moisture content, and storage duration on germination indices and electrical conductivity of bean seeds were significant (P<0.1). The germination trend during storage at 15 °C and seed moisture content of 6% decreased from 94% to 81% after 270 days of storage, so that germination decreased to 35% under similar moisture content after 270 days of storage as temperature increased from 15 to 45 °C. As the storage time passed, electrical conductivity increased and this increase was more pronounced at higher temperatures. Viability constants were calculated 9 months after storage using the seed viability equation, in which KE, CH, CW, and CQ were calculated -5.39697, 0.03201, 2.13041, and 0.000017, respectively.

The results showed that the electrical conductivity of the leaked material increased with increasing storage temperature and seed moisture content, which led to lower viability of seeds. At 15 °C and 6% seed moisture content provided better conditions for seed survival during the 9-month storage time compared with all other temperatures and moistures and had the lowest rate of deterioration. The results showed that with increasing seed temperature and moisture so that they had to lowest electrical conductivity of the leaked material from seeds and deterioration rate.

In spite of optimal qualitative traits of sweet corn plant, its cultivation is limited due to some problems in germination, poor vigor, seed wrinkling and seedling weak establishment in the soil, using mineral compounds in seed coating could improve germination and seedling growth indices, and physical characteristics of sweet corn seeds. In order to improve efficacy of sweet corn seed using seed coating, this experiment was conducted based on three-factor factorial in a completely randomized design with four replications of 25 seeds at the laboratory at the Department of Agronomy and Plant Breeding, Yasouj University, Iran, in 2018. The first factor included the concentrations of chitosan solutions (zero- 0.3% acetic acid, 0.5 and 0.75%), the second factor was gum arabic (zero- distilled water and 0.4%) and the third factor was V10K2.5P5 coating composition (10, 2.5 and 5 fold to seed weight respectively in Vermiculite (V), kaolin (K) and perlite (P)) and no coating treatment. The interaction effect showed that that the highest seedling length vigor index (183.24) was related to the coating treatment of gum arabic 0.4% and coating composition of V10K2.5P5 that had a significant difference with a treatment that had the lowest seedling length vigor index (85.70) from the coating treatment gum arabic 0.4% and no coating composition. The overall results showed that the coating treatment of chitosan 0.5% + coating composition of V10K2.5P5 + gum arabic 0.4% was more effective treatment on germination indices and seedling and physical characteristics of sweet corn seeds compared to other treatments.

 Sweet corn (Zea mays var. saccharata) is a corn variety that is distinguished from other varieties due to the presence of genes that affect starch production in the endosperm. Given that the most of plants including sweet corn face with problems such as non- uniform germination and poor seed emergence in the early stages of germination. Thus, the use of organic stimulants is one of the ways to reduce the harmful effects of non-biological stresses, increase seed germination, uniform appearance and increase their yield and quality. The present study was carried out to investigate the effect of different concentrations of chitosan on seed germination and some biochemical traits of sweet corn under osmotic potential conditions.

 To investigate the effect of chitosan and osmotic stress on germination and biochemical parameters of sweet corn, a factorial experiment was conducted in a completely randomized design with four replications at the Seed Technology Laboratory, Faculty of Agriculture, Yasouj University in 2017. The first factor was osmotic stress at 0, -3, -6, and -9 bar osmotic potentials and the second factor was pre-treatment at five levels of chitosan zero, 0.25%, 0.5%, 0.75% and 1% and one level of distilled water. The seeds were immersed in the desired solutions of chitosan for 3 hours at 25 °C and under dark conditions, and then the pre-treated seeds were germinated under standard germination condition. In each petri dish, 25 seeds were placed on a filter paper and osmotic potential was applied using polyethylene glycol 6000. Seed germination was carried out in the germinator at 25 ± 1 ° C for 7 days under dark conditions. The germination traits and biochemical traits were measured according to standard methods.

 Osmotic stress reduced germination percentage and germination rate, seedling vigour length index, germination uniformity coefficient, allometric coefficient, and soluble protein content and also increased the mean germination time, proline, soluble sugar content and hydrogen peroxide. Pre-treatment of seeds with a concentration of 0.5% chitosan increased protein, proline, and soluble sugars content at all osmotic stress levels. At the osmotic stress levels, the highest and lowest levels of hydrogen peroxide respectively were observed in 0.5% chitosan treatment and distilled water treatment. The results showed that pre-treatment with 0.5% chitosan increased germination percentage and rate and seedling vigour length index, and also reduced the mean germination time and malondialdehyde. Pre-treatment of seed with zero and 1% chitosan led to reduction in some of the germination and biochemical traits in comparison with 0.25, 0.5, and 0.75% chitosan.

 The results showed that seed treatment with 0.5% chitosan could reduce the harmful effects of osmotic potential on some germination and biochemical traits in sweet corn seedlings and improve seedling growth.

1-Chitosan increases the germination percentage and germination rate.
2-Chitosan increases soluble sugars, proline, and soluble protein.
3-Chitosan reduces the amount of malondialdehyde and hydrogen peroxide.