Evaluating genetic variability in celery (Apium graveolens L.) genotypes through morpho-anatomical and pollen trait analyses

Understanding a population's genetic diversity is essential for optimizing the effectiveness of breeding programs. Stomatal traits and pollen viability are essential parameters influencing plant physiological performance and reproductive fitness, making them crucial for assessing genetic variability among celery genotypes. This research aimed to achieve two primary objectives: 1) to study the genetic variability among celery genotypes based on morpho-anatomical traits in leaves, including stomata number (NS), polar diameter (PD), equatorial diameter (ED), stomatal area index (SAI), stomatal density (SD), stomatal index (SI), stomatal functionality (SFUN), dry weight (DW), leaf area (LA), and specific dry weight (SDW); and 2) to find out a reliable staining method for estimating pollen viability in celery genotypes. The Scott-Knott test revealed genotypic variability, demonstrating genetic variability among the evaluated 20 celery genotypes. Data analysis included principal component analysis (PCA) and unweighted pair group method with arithmetic mean (UPGMA) clustering, which classified the genotypes into three groups. Notably, the genotypes PB-CEL-1, PAU1, PAU3, PAU8, and A-CEL-1 clustered together, exhibiting high values for the studied traits. Among these traits, the SAI was the significant variability contributing trait. Five staining methods were used to estimate pollen viability. Out of these, alexander, acetocarmine, and methylene blue methods effectively distinguishing viable and non-viable pollens. These findings highlight the potential of celery genotypes for future breeding programs.