The study aims to address the impact of drought stress on chickpea production, identifying drought-tolerant genotypes through comprehensive evaluation methods. Chickpeas, known scientifically as Cicer arietinum, are pivotal food legumes cultivated across 13 million hectares around the globe, predominantly thriving under tropical and subtropical climates. Unfortunately, these crops face substantial challenges due to frequent and prolonged droughts, particularly within arid and semi-arid regions. A group of researchers from the ICAR-National Institute of Abiotic Stress Management conducted field studies over two years (2020-21 and 2021-22) to assess various chickpea genotypes in response to water-limiting conditions. This research holds immense importance for improving chickpea resilience against drought, ensuring food security, and supporting agricultural sustainability.
Conducted at the ICAR-NIASM research farm located in Baramati, Maharashtra, the study involved 25 chickpea genotypes and utilized both well-watered (control) and stress (drought) conditions within its experimental design. With substantial annual rainfall averaging around 560 mm, the site provided suitable conditions to evaluate the genotypes effectively. The objective was to identify genotypes exhibiting enhanced drought tolerance, which is particularly important as over 50% of chickpea production variability stems from abiotic stress, especially moisture deficits.
The experiment implemented various drought stress indices, including the stress tolerance index (STI), mean relative performance (MRP), and relative efficiency index (REI), aiming to differentiate between genotypes effectively. The results revealed significant interaction effects among the genotypes, water treatments, and their respective years, highlighting the complexity of responses to drought conditions.
Results indicated noteworthy variations, showcasing high drought tolerance among specific genotypes including BDG75, BGD103, Digvijay, ICCV92944, ICC4958, and JG16, which were characterized by superior performance across different assessments. For example, during 2021-22, BDG75 achieved yields of 10.76 grams under drought stress, demonstrating its ability to thrive even when conditions are less than optimal. On the lower end of the spectrum, genotypes such as ICCV96030, JG63, GNG1581, JG12, PG186, GG2, Pusa362, and SAKI9516 faced significant challenges and were classified as sensitive under drought stress.
Researchers initiated water stress conditions at the flowering phase by withholding irrigation, effectively simulating drought scenarios. Through the application of various stress tolerance indices, researchers gathered insights to classify the chickpeas accurately. The study utilized techniques such as principal component analysis (PCA) and cluster analysis, which illuminated the relationships between the genotypes. The first cluster comprised high-performing genotypes indicating strong drought tolerance, characterized by beneficial indices related to stress and yield stability.
Throughout both years, the results exhibited correlations between yield under stress conditions and the indices, where the stress tolerance index (STI) showed a strong positive relationship with yield performance. The research reported impressive correlation coefficients, such as 0.97 for yield under stress conditions relative to STI, underscoring the significance of this index as a powerful tool for identifying drought-tolerant chickpee genotypes. Conversely, the relative decrease index (RDY) exhibited negative correlations with seed yield, pointing to its potential utility for identifying sensitive genotypes.
Determining genotype performance against varying degrees of water stress provided valuable insights, as these assessments are integral for breeding and developing varieties adept at handling adverse conditions. Genotype assessments revealed how certain traits allow various chickpeas to flourish under less favorable environments. For example, traits such as deep root systems, efficient water utilization, and the ability to sustain cellular functions are key to maintaining growth even during water scarcity.
The analysis concluded with recommendations for future breeding efforts focused on enhancing traits associated with water stress tolerance. A key takeaway suggested integrating the stress tolerance index (STI) and relative efficiency index (REI) as reliable tools for screening chickpea genotypes under drought conditions. These findings serve as actionable insights for breeders aiming to develop higher-yielding, drought-resilient chickpea varieties capable of sustaining agricultural productivity even as climate variability poses increasing challenges.
Overall, the study effectively used modern techniques to delineate genotypes with the best potential to withstand drought stress – paving the way forward for future research and agricultural practices. These findings encourage the development of varieties grounded on these traits, with the goal of ensuring optimal performance across varied environmental conditions.