Genetic Diversity Assessment in Crop Germplasm Improvement

Genetic diversity underpins the capacity of crop populations to adapt to environmental change and to meet evolving agricultural demands. Assessment of this diversity within germplasm collections employs a combination of phenotypic characterisation, molecular marker analysis and increasingly high-throughput genomic approaches. Molecular markers such as SSRs, ISSRs and start-codon-targeted (SCoT) loci reveal allelic variation, while next-generation sequencing and SNP arrays permit genome-wide surveys of polymorphism. Quantitative indices—Nei’s genetic diversity, Shannon’s information index and polymorphism information content—provide standardised measures of variation. By assembling core collections through maximisation algorithms, breeders and conservationists can focus on representative subsets that capture the breadth of allelic resources. Such efforts support the discovery of novel alleles for disease resistance, drought tolerance and yield enhancement, inform marker-assisted and genomic selection strategies, and ensure the long-term resilience of global food systems.

Research from Nature Portfolio

A comprehensive analysis of eight olive cultivars from a key production region combined morphological, chemical and anatomical traits with both inter-simple-sequence repeat (ISSR) and SCoT markers. The integrated approach detected high levels of polymorphism, with polymorphism information content values around 0.48 for ISSRs and 0.44 for SCoTs, and resolved cultivars into two principal genetic clusters. Concordance between molecular and phenotypic dendrograms demonstrated the complementary power of marker systems and traditional characterisation. The study highlighted SCoT markers as an efficient, informative tool for elucidating relationships among closely related cultivars and for guiding selection of parent lines in breeding programmes.

Genetic Diversity Assessment in Crop Germplasm Improvement publication trend

The graph below shows the total number of articles in genetic diversity assessment in crop germplasm improvement across all publications each year (not limited to Nature Index journals).

Technical terms

Germplasm: The hereditary material of crop species and their wild relatives maintained in collections for breeding and conservation.

Molecular marker: A DNA sequence variation used to detect genetic differences among individuals or populations.

Polymorphism Information Content (PIC): A measure of the discriminating power of a genetic marker based on allele frequency.

Core collection: A representative subset of germplasm chosen to maximise genetic diversity while minimising redundancy.

Start-Codon-Targeted (SCoT) marker: A gene-targeted marker system that amplifies regions surrounding the ATG start codon to reveal polymorphisms.

References

1. Genetic diversity analysis in wheat cultivars using SCoT and ISSR markers, chloroplast DNA barcoding and grain SEM. BMC Plant Biology (2023).
2. Genetic diversity, chemical constituents and anatomical analysis of eight popular Olive (Olea europaea L.) cultivars in Al-Jouf region, Saudi Arabia. Scientific Reports (2024).
3. Genetic Diversity, Conservation, and Utilization of Plant Genetic Resources. Genes (2023).
4. Utilization of Molecular, Phenotypic, and Geographical Diversity to Develop Compact Composite Core Collection in the Oilseed Crop, Safflower (Carthamus tinctorius L.) through Maximization Strategy. Frontiers in Plant Science (2016).