Assessment of genetic diversity in Fusarium oxysporum f. sp. ciceri populations based on SSR markers

Abstract

Chickpea (Cicer arietinum L.) is a major pulse crop whose productivity is severely affected by wilt disease caused by Fusarium oxysporum f. sp. ciceri. The pathogen exhibits high variability in virulence and adaptability, leading to frequent breakdown of host resistance. Understanding the genetic diversity of Fusarium oxysporum f. sp. ciceri populations is therefore essential for effective disease management and resistance breeding. In the present investigation, forty Fusarium oxysporum f. sp. ciceri isolates collected from diverse geographical regions of India were characterized using ten Simple Sequence Repeat (SSR) markers. Genomic DNA was extracted using the CTAB method and PCR amplification was carried out with selected SSR primers. The amplified products were scored as binary data and analyzed using NTSYS-pc software. Genetic relationships among isolates were assessed through Neighbor Joining (NJ) cluster analysis. A total of 827 amplicons were generated, all of which were polymorphic, revealing 100% polymorphism with an average of 82.7 amplicons per primer. Amplicon sizes ranged from 50 bp to 1800 bp, indicating high allelic diversity. The NJ dendrogram grouped the isolates into two major clusters, reflecting moderate to high genetic variability. Similarity coefficients ranged from 0.17 to 0.75, confirming substantial genetic heterogeneity among the isolates. The results demonstrate that SSR markers are highly effective in discriminating Fusarium oxysporum f. sp. ciceri isolates and reveal significant genetic diversity within the pathogen population. This information is valuable for understanding pathogen evolution and for the development of durable wilt resistant chickpea varieties.