Screening of Chickpea (Cicer arietinum L.) Genotypes for Salinity Tolerance at Early Growth Stages

IntroductionChickpea is an important source of energy and protein of the Iranian people’s diet. Iran is one of the main centers of genetic diversity of this crop. The cultivation of chickpea nowadays is practiced using irrigation or supplemented irrigation in many parts of Iran, as more challenging by climate change, precipitation decline, and salinization of underground water resources. On the other side, there is no enough fresh water to meet the full water requirement of chickpea. Although chickpea consider as a salt sensitive crop but there are some reports that show some variable reaction to salinity amongst different chickpea genotypes. A collection of cold and drought stress tolerant chickpea genotypes are maintained in Mashhad Chickpea Collection (MCC) in the Plant Science Research Center of Ferdowsi University of Mashhad. Therefore, testing the tolerance of different genotypes and landraces of this crop to salinity stress is of important, and this experiment is arranged to test salinity tolerance of chickpea genotypes in this collection. Materials and MethodsIn order to identify and assess of chickpea genotypes salinity tolerant, seeds of 206 Mashhad Chickpea Collection genotypes were kindly prepared by Plant Science Research Center of Ferdowsi University of Mashhad (FUM). The experiment was carried out in the research green house of Faculty of Agriculture of FUM at the spring of 2021 which light was normal, and temperature and humidity were controlled. A randomized complete block design was used with three replications and each treatment consist of 10 plants for each genotype. Seeds were sown in the shallow trays in the lab at 25 degrees centigrade and emerged seedling were transplanted in the sand culture medium. Saline water prepared by adding NaCl to tap water till its EC reached to 12 dS.m-1. Salinity imposed after a week of transplanting through the Hoagland nutrient solution and continued for four weeks. Nutrient solution was renewed each week and 12 dS.m-1 NaCl dissolved in that solution. Measured traits included the height difference at the beginning of the imposing of salt stress and for weeks later, number of branch per plant, survival percentage, and biomass accumulation. Sodium and potassium content of shoots. Data were analyzed using Minitab for windows 17 and standard error and cluster analysis arranged using JMP4 software. Results and Discussion The results showed that 31 genotypes have a survival rate of 76-100% which 10 genotypes showed survival rate of 100%. Plant height, biomass, and number of lateral branches per plant decreased as survival rate decreased. Significant increase in shoot Na+ concentration was only found in survival range of 0-25% while the shoot sodium content was the lowest in in group of 57-100% survival compared to the other three groups. Biomass accumulation also reduced more rapidly in low survival group (0-25%) compare with 76-100% survival group by 66%. The correlation analysis showed that survival rate, plant height and number of lateral branches per plant, biomass, plant height difference and shoot K+ concentration showed significantly positive correlation. Based on factor analysis, three factors were selected that in total 79% of the total variation was explained. The first and second factors were explained high percent of variation that include survival rate and plant height and number of lateral branches per plant, biomass, plant height difference and Na+ concentration. Genotypes MCC1782, MCC197 ,MCC1703 ,MCC1568, MCC1573, MCC1737, MCC1209, MCC1516, MCC1493, MCC1832, MCC1957, MCC1721, MCC2016, MCC1704, MCC1641, MCC1815, MCC1775, MCC178, MCC1754, MCC1627, MCC1716, MCC1918, MCC1827 ,were selected as the superior genotype under salinity stress of 12 dS.m-1  for four weeks. According to the result of cluster analysis, the genotypes were classified in four clusters. The genotypes of the third and fourth clusters had a high average salinity tolerance compared to other clusters with the investigated traits. ConclusionsWhile chickpea is not traditionally considered a salt-tolerant crop, the observed variations among genotypes suggest that further efforts are required to screen and identify salt-tolerant genotypes and landraces for potential inclusion in breeding programs. It's important to note that the current study was conducted in a controlled environment, with only a few weeks of exposure to salinity treatment. Consequently, we propose a more extensive experiment that includes those genotypes exhibiting superior performance in terms of survival rate, biomass accumulation, low shoot sodium content, and high potassium content.