Grouping of Candidate Drought Tolerant Genotypes of Chickpea (Cicer arietinum L.) based on Yield and Yield Components in Different Planting Dates in Water Deficit Conditions

IntroductionGiven the expected population growth in the coming years and the necessity to provide food for people, legumes, especially chickpeas (Cicer arietinum. L), hold significant importance in terms of economics, nutrition, soil improvement, and crop rotation. Legumes are considered one of the most important sources of protein in most developing countries. Researchers believe that early cultivation of chickpeas leads to better performance due to the longer vegetative growth period and concurrent reproductive phase with appropriate rainfall and desirable moisture. On the other hand, studies show that spring planting of chickpeas leads to a reduction in all growth factors due to the simultaneous sensitive growth stages with water deficit and drought stress. This study was conducted to grouping of candidate chickpea genotypes in response to water deficit based on their yield performance and components at different planting dates. Materials and MethodsThis study was conducted at the research farm station of the Faculty of Agriculture, Ferdowsi University of Mashhad, in the year 2018-19. In this research, six genotypes and two cultivars were evaluated in a randomized complete block design with four replications as a split-plot design. Seeds were obtained from the seed bank collection of Research Center for Plant Sciences, Ferdowsi University of Mashhad. Planting was done in two dates in 5 March and 13 April with a density of 40 plants per square meter. Also, irrigations were done only at two stages; the first stage was irrigated with the purpose of achieving the emergence and the second irrigation at the time of 50% flowering with 20 mm in both stages. To measure traits such as emergence time, flowering time (50% of plants in flowering stage) and biomass, plant height, number of pods per plant, percentage of fertile pods, and 100-seed weight at the end of the growth stage and harvest time, five plants were randomly selected from each plot, and the desired traits were examined and recorded. At the time of full maturity and drying of the plants, after removing half a square meter margin from each plot, biological and seed yield were measured, and for calculating biological yield, the dry weight of seeds was added to the dry weight of plant residues. Results and DiscussionThe results indicated a significant superiority in all traits for the first planting date (5 March) compared to the second planting date (13 April). Significant differences were observed among the different genotypes in terms of emergence percentage, days to maturity, plant height, days to flowering, biological yield, podding, and seed yield. Genotype MCC352 had the highest number of pods per plant (34 pods), and genotype MCC427 had the highest number of days to flowering. Genotype MCC537 was superior in plant height and biological yield, but genotype MCC696 was superior in days to maturity and seed yield, indicating that these two genotypes had better responses to environmental conditions. Based on cluster analysis of chickpea genotypes in the first planting date, eight genotypes were classified into four clusters. Cluster 1 included genotypes MCC352, MCC537, MCC552, MCC80, and Jam cultivar. Cluster 2 included Samin cultivar. Cluster 3 included genotype MCC427, and cluster 4 included genotype 696MCC. Cluster 1 had the highest coefficients in terms of emergence percentage and days to maturity, and cluster 2 had the highest coefficients of days to maturity and days to flowering. Similarly, in the second planting date, eight chickpea genotypes were classified into three clusters. Cluster 1 included genotypes MCC696, MCC537, MCC552, MCC80, and Jam cultivar. Cluster 2 included genotypes MCC352 and MCC427. Cluster 3 included Samin cultivar. Cluster 1 had the highest coefficients in terms of emergence percentage and days to maturity, and cluster 2 had the highest coefficients of days to maturity and emergence percentage. Furthermore, the Principal Component Analysis of the studied genotype traits showed that in the first planting date (5 March), PC1 (43.4%) and PC2 (25.7%) accounted for a total of 69.1% of the variance, while in the second planting date, PC1 (36.8%) and PC2 (27%) accounted for a total of 63.3% of the variance. Overall, the studied genotypes had better performance and yield components in the first planting date. ConclusionsIn general, it can be concluded that delayed planting and exposure to drought stress during the critical growth stages of the plant at the end of the season resulted in a decrease in chickpea yield and its components. It was observed that planting chickpea on time to avoid late drought stress at flowering and podding stages would lead to a better yield and its components.