عنوان مقاله [English]
The agricultural sector needs to reduce the use of freshwaters and using low quality waters instead of increasing demand for domestic and industrial water uses, along with the reduction of groundwater level. Therefore, using saline water in the future for agricultural production is unavoidable. The soil fertility has been reduced due to decreasing the quality of water resources and increasing salinity in agriculture lands. Saline water and saline soil contain high concentrations of salts such as calcium sulfate and sodium carbonate, although sodium chloride is the dominant salt. Salt stress affects various physiological and metabolic processes in plant and may eventually impede crop production depending on the extent and severity of the stress. In the early stages, a high concentration of solutes present in the soil brings about osmotic stress which reduces the capacity of root systems to absorb water and, that start the loss of leaves water. This is accompanied by ion-specific effects that cause the accumulation of toxic concentration of Na+ and Cl− in the cells, which manifest in the form of chlorosis and necrosis. Planting legumes in saline soil is important for conservation of sustainability of production. However, legumes, including chickpea, show low-salinity tolerance and loss yield in saline conditions. To permit crop growth on natural saline soils considerable enhancement of salinity tolerance could be required for the chickpea which is a relatively salt sensitive legume. Therefore, identification and introduction of salt tolerated chickpea cultivars help sustainable crop production in moderate saline areas.
Materials and Methods
This study was carried out under hydroponic conditions in the greenhouse of Research Center for Plant Sciences, Ferdowsi University of Mashhad. The experiment was conducted as a completely randomized design with three replications to evaluate salinity tolerance of 140 Deci-type chickpea genotypes during seedling stage in a salinity level of 12 dSm-1 NaCl. Hoagland solution had been used in the sand culture method. Recirculating nutrient system was applied, nutrient solution was replaced weekly and salinity of nutrient solution was adjusted daily, but no acidity adjustments were made in the Hoagland solution. Four weeks after salinity application, growth stages, height plant, branch number, survival percentage, remained leaves, shed leaves, membrane stability index, sodium and potassium concentration were measured.
Results and Discussion
Results indicated that survival percentage of 21 genotypes was more than 76% among which, six genotypes of MCC18، MCC22، MCC29، MCC59، MCC136 and MCC430 showed 100% survival. In the survival range of 76-100, 51-75, 26-50 and 0-25%, 43, 57, 42 and 16 percent of genotypes were in the post-flowering stages, respectively. Plant height increased with increasing survival range, so that the genotypes in the survival range of 76-100% were 4, 5 and 12 cm higher than the survival range of 51-75, 26-50 and 0-25%, respectively. The highest plant was observed in MCC59 genotype with 100% survival range. The lowest number of branches per plant was observed in the 0-25% survival range. With increasing survival range percentage of shed leaves decreased and the percentage of remained leaves increased. The same percentage of shed leaves and the remained leaves were observed in the survival range of 76-100% and 51-75%. In three survival range 76-100%, 51-75%, and% 26-50, the shed leaves were about 50%. The highest percentage of remained leaves (73%) was observed in MCC177 genotype with 75% survival. The membrane stability index increased with raise up survival range. There were no difference in survival range of 26-50 and 51-75% in membrane stability index, but in the survival range of 76-100%, membrane stability 6% increased compared to the two previous survival ranges. The highest membrane stability index observed at MCC34 (53%) and MCC179 (52%) with 85%, 51% survival, respectively. However, among genotypes in 100% survival some genotypes, such as MCC29 and MCC136, had a relatively low membrane stability index. With rising up survival range, sodium concentration decreased and potassium increased. Sodium to potassium ratio was also decreased with increasing survival range. Dry matter productions per plant increased with improving survival range. Dry matter from 0-25% to 26-50%, 51-75% and 76-100% survival range, increased 16%, 24%, and 38%, respectively. MCC4, MCC43, MCC22, MCC49, MCC59 and MCC85 had the highest dry matter productions.
The correlation between traits showed the positive correlation between survivals and remained leaves which is depended on maintaining membrane stability and decreasing sodium uptake in plant. Based on this information, chickpea genotypes have salt tolerance mechanisms and it is possible to use these genotypes for breeding programs for moderate salinity stress conditions.