Genetic Variability and Association Analysis of Underground and Aboveground Morphological Characteristics of Wild Cicer Species and Cultivated Chickpeas

Background: Wild relative species of cultivated plants possess resistance genes to withstand a/biotic stresses to survive in their natural environments. Although aboveground morphological characteristics of wild species were evaluated in breeding programs, underground morphological characteristics have usually been ignored due to difficulties working with underground materials. Methods:The present study was therefore conducted to perform comparative analyses of the underground and aboveground morphological characteristics of wild Cicer species -including 20 accessions of Cicer reticulatum, and 6 accessions of Cicer echinospermum- and 1 variety of cultivated C. arietinumspecies. Root length (RL), root dry (RDW) and fresh weight (RFW), number of nodules per plant (NNP), nodule fresh (NFW) and dry weight per plant (NDW) in flowering time were studied as underground morphological characteristics. Plant height (PH), stem dry (SDW) and fresh weight (SFW) were recorded as above morphological characteristics. Results:Significant morphological differences were observed between the wild accessions and cultivated chickpeas cultivars. The wild Cicer species exhibited superior root development with higher nodule fresh and dry weight ratio compared to the cultivated chickpea. The wild accessions sustained their root development despite extremely dry and hot periods compared to the cultivated variety. For broad sense heritability estimates, root and shoot traits showed moderate to high heritability while nodule traits exhibited low heritability. Compared to the other traits, highest phenotypic and genotypic variance were observed NNP. Higher phenotypic variances observed for root and nodule traits indicated quantitative nature of inheritance and high impact of environmental factors for the traits. Genotypic correlation coefficients were found higher than phenotypic correlation coefficients in most of the characters, indicating the presence genetic association among traits which is important for reliable improvement through selection. Path coefficient analysis revealed that NNP, RDW, and SFW had strong positive direct effects on SDW, indicating their importance in enhancing biomass accumulation in chickpea. Principal component (PCI) analysis clearly distinguished wild accessions based on the evaluated traits and explained 79.54% of the total variation, with PC1 accounting for 68.10%. Traits contributing most strongly to PC1 included SDW, SFW, RFW and RDW. PC2 was influenced mostly by nodulation traits including NDW, NFW, and the NNP. Domestication appeared to favor aboveground traits in cultivated chickpea compared to wild accessions. These findings underline the potential of wild Cicerspecies as valuable genetic resources for developing drought-resistant varieties.