Understanding Genetic Diversity and Family Tree of Onions Using DNA Markers

Jenn Hoskins
7th June, 2024

Understanding Genetic Diversity and Family Tree of Onions Using DNA Markers

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Central Agricultural University studied the genetic diversity of 95 Allium accessions using 19 SSR markers
  • They found 92 polymorphic loci with an average of 4.84 loci per marker, showing wide genetic variability
  • The study identified four main genetic clusters and 13 sub-clusters, aiding future breeding programs for better Allium crops
The genus Allium, which includes widely known crops like onions, garlic, and leeks, as well as several lesser-known species, is a cornerstone of agricultural biodiversity. These underutilized species hold immense potential for breeding programs aimed at improving resistance to various environmental stresses. However, to harness this potential, a comprehensive understanding of the genetic diversity and population structure within this genus is crucial. A recent study conducted by researchers at the Central Agricultural University has made significant strides in this area by employing nineteen Simple Sequence Repeat (SSR) markers to analyze the genetic divergence and population structure of 95 Allium accessions, including species, varieties, and interspecific hybrids[1]. The study revealed 92 polymorphic loci, with an average of 4.84 loci per SSR marker. Polymorphic Information Content (PIC) values, which measure the informativeness of a genetic marker, ranged from 0.24 to 0.98, indicating a wide variability in the genetic markers used. The cross-transferability of these SSR markers among different Allium species was relatively low, ranging from 1.33% to 10.53%. This suggests that while SSR markers are useful, their applicability across different species within the genus is limited. The genotypes analyzed were grouped into four primary clusters (A, B, C, and D) with 13 sub-clusters (I-XIII), as determined by clustering results. Population structure analysis further supported this clustering, indicating that the population is predominantly segregated into four distinct groups. This detailed genetic mapping holds promise for refining future breeding programs aimed at developing elite Allium progenies with enhanced traits. This study builds on previous research efforts aimed at understanding the genetic diversity within the Allium genus. For instance, a study on Lou onion (Allium fistulosum L. var. viviparum) in China utilized the SLAF-seq method to analyze the genetic diversity of 122 onion accessions, revealing close genetic relationships among specific accessions and providing valuable insights into the germplasm of Lou onion[2]. Similarly, research on Indian onion breeding has focused on characterizing breeding lines, varieties, hybrids, and exotic accessions for cytotype and Ms locus, which are crucial for the development of hybrid onions with high productivity and uniformity[3]. Moreover, earlier studies have also explored the genetic relationships of onion lines concerning disease resistance. For example, research on gray mold resistance in onions identified specific genes related to resistance traits, thus supporting the breeding of disease-resistant onion lines[4]. Another study reviewed the challenges posed by anthracnose and twister disease in onions, emphasizing the need for resistant varieties to improve productivity and profitability[5]. The current study by the Central Agricultural University ties together these previous findings by providing a more comprehensive understanding of the genetic diversity within the Allium genus. By employing SSR markers, the study adeptly unravels the complexities of diversity, thereby offering a robust framework for future breeding programs. These findings are particularly significant as they pave the way for developing Allium species with improved resistance to environmental stresses and diseases, ultimately contributing to sustainable agricultural practices. In summary, the study's insights into the genetic diversity and population structure of Allium species hold substantial promise for refining breeding programs. By leveraging the detailed genetic mapping provided by SSR markers, researchers can more effectively target elite progenies with desirable traits, thereby enhancing the resilience and productivity of Allium crops. This research not only builds on but also substantially advances our understanding of Allium genetics, offering a valuable resource for future agricultural innovations.

GeneticsBiochemPlant Science


Main Study

1) Deciphering genetic diversity phylogeny and assembly of Allium species through micro satellite markers on nuclear DNA.

Published 15th June, 2024 (future Journal edition)


Related Studies

2) Genome-wide assessment of population structure and genetic diversity of Chinese Lou onion using specific length amplified fragment (SLAF) sequencing.


3) Molecular marker-based characterization of cytoplasm and restorer of male sterility (Ms) locus in commercially grown onions in India.


4) Using Transcriptome Analysis to Explore Gray Mold Resistance-Related Genes in Onion (Alliumcepa L.).


5) Anthracnose of Onion (Allium cepa L.): A Twister Disease.


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