Genetic Diversity of Phelipanche ramosa Populations Infesting Tomato and Carrot Fields Using SSR Markers

Abstract

Phelipanche ramosa is a holoparasitic weed causing severe yield losses in solanaceous and umbelliferous crops, particularly tomato and carrot. Understanding its genetic diversity is essential for developing effective management strategies. The present study assessed the genetic diversity of P. ramosa populations collected from tomato and carrot fields using simple sequence repeat (SSR) markers. Parasitic shoots were collected from different agroecological regions, and genomic DNA was extracted for PCR amplification using selected polymorphic SSR primers. The amplified products were analyzed to determine allelic variation, polymorphism levels, and genetic relationships among populations. Results revealed a high level of genetic diversity within and among P. ramosa populations, indicating significant gene flow across regions and host crops. SSR analysis generated distinct multilocus genotypes that clustered populations based on geographic origin rather than host specificity, suggesting limited host-driven genetic differentiation. However, some population structure was observed, indicating partial adaptation to local environmental conditions and cropping systems. Analysis of molecular variance (AMOVA) showed that most genetic variation occurred within populations rather than between populations. Cluster and principal coordinate analyses further confirmed the presence of genetically diverse groups with overlapping distribution patterns. The study highlights the adaptive potential of P. ramosa and its ability to persist across different host environments. These findings emphasize the importance of integrated management strategies that consider the genetic variability of the parasite, including crop rotation, resistant varieties, and sanitation practices. Overall, SSR-based molecular analysis provides valuable insights into the population structure and evolutionary dynamics of P. ramosa, contributing to improved management of this economically important parasitic weed in vegetable cropping systems.