?Effect of priming and temperature on emergence and establishment of two lentil (Lens culinaris Medik.) genotypes featuring low and high seed vigor

Beans, due to their significant nutritional and crop characteristics, have a high rank in agricultural systems of the world. These plants, by fixing air nitrogen, can increase the amount of nitrogen in the soil. Beans have a long history of cultivation in Iran, and some believe that some of them, such as lentil (Lense culinaris Medik) and chickpea (Cicer arietinum L.), have been domesticated in this country. The lentils are cold and long day and can be cultivated from 0 to 3500 m above sea level, the temperature suitable for growing lentils is 15-25 °C. Spring cultivation of lentils although common in Iran, winter cultivation of lentils has advantages over spring cultivation if successful. Previous research showed that the average plant height of lentils in autumn and winter was 43% higher than spring planting and the highest yield of lentils (1486 kg.ha-1) was obtained from autumn planting. Autumn cultivation is usually accompanied by a low temperature challenge. Low temperatures often affect the growth and productivity of crops, causing significant crop losses. Delay in emergence and decrease in germination percentage of seeds occur due to autumn cold, so priming can be used for seed germination. The purpose of this study was the effects of different priming treatments on reducing cold stress effects on emergence and growth of two lentil genotypes.
 
The experiment was conducted as a factorial based on completely randomized design with four replications under controlled conditions in 2017 at Ferdowsi University of Mashhad. Factors consisted of lentil genotypes (Robat and Calposh), priming (6 levels of control, Gibberellic acid )C19H22O6(, Potassium nitrate (KNO3), Zinc sulphate (ZnSO4), seed priming Dayan and hydropriming) and temperature (5, 10 and 15ºC). To test and apply treatments, 40 seeds were randomly selected for each treatment. After the end of the priming period (16 h), the seeds were removed from the solution and then placed in the laboratory for 24 h until complete drying. The prepared seeds were 10 seeds in pots of 11 cm diameter light soil and transferred to the growth chamber. Then the studied properties were measured. Data were analyzed using SAS 9.4 software and the means were compared with LSD at 5% probability level.
 
The highest emergence percentage (72.5%) was found in Robat in control and 5ºC. Seed vigor in Robat genotype at 15 °C was higher than Calposh genotype, and in both genotypes (with the exception of Calposh genotype the priming primer with zinc sulphate and hydro-priming), the seed vigor increased with temperature. The highest seed vigor (4.91) was found in Robat in 15ºC and priming by seed priming Dayan. The highest plant height was observed in priming by gibberellic acid and 15ºC. In both genotypes, leaf number per plant was increased as temperature increased and was decreased when treated by ZnSO4 and Hydropriming in Calposh. The highest leaf number per plant (4 leaves) was found in Robat in 15ºC and priming by seed priming Dayan. The highest root length (4.04 cm) was observed in seed priming Dayan and 15ºC. The interaction of temperature and priming on root length showed that at 5 °C all priming treatments (with the exception of sulfate priming) compared to the control, at 10 °C priming with Dayan seed solution, potassium nitrate and 15 °C hydropriming. Dayan seed solution and potassium nitrate had more root length than control. Seedlings Robat appear to have higher seed vigor and can compensate for the time elapsed before priming, but seedlings Calposh that are less potent, priming treatments have been able to improve seed vigor.
 
The results of this study showed that the Robat genotype in terms of seed vigor and other emergence characteristics was better than Calposh genotype. As the Robat genotype has higher vigor, so different priming treatments could not have a positive effect. Priming with gibberellic acid and potassium nitrate had the greatest effect in reducing the effects of low temperature (5 °C) on the emergence characteristics of lentil seed. In general, priming with gibberellic acid seeds for autumn or early spring cultivation can be recommended.