No abstract

The oil palm (Elaeis guineensis Jacq.) is one of the major cultivated crops among the economically important palm species. It is cultivated mainly for its edible oil. For a perennial crop like oil palm, the use of Marker Assisted Selection (MAS) techniques helps to reduce the breeding cycle and improve the economic products. Genetic and physical maps are important for sequencing experiments since they show the exact positions of genes and other distinctive features in the chromosomal DNA. This review focuses on the role of genome mapping in oil palm breeding. It assesses the role of genome mapping in oil palm breeding and discusses the major factors affecting such mapping. Generating a high-density map governed by several factors, for instance, marker type, marker density, number of mapped population, and software used are the major issues treated. The general conclusion is that genome mapping is pivotal in the construction of a genetic linkage map. It helps to detect QTL and identify genes that control quantitative traits in oil palm. In perspective, the use of high-density molecular markers with a large number of markers, a large number mapping population, and up-to-date software is necessary for oil palm genome mapping.

Good knowledge about genome properties of the populations helps to optimize breeding methods, particularly genomic selection (GS). In oil palm (Elaeis guineensis Jacq.), the first global source of vegetable oil, GS gave promising results. The present study considered two complex oil palm breeding populations, Deli and La Mé, with 943 individuals and 7,324 single-nucleotide polymorphisms (SNPs) from genotyping-by-sequencing. Linkage disequilibrium (LD), haplotype sharing, effective size (Ne), and fixation index (Fst) were investigated. A genetic linkage map was constructed, including 4,252 SNPs and spanning 1,778.52 cM, with an average recombination rate of 2.85 cM/Mbp. The LD at r²=0.3, considered as the minimum to get reliable results for genomic predictions, spanned over 1.05 cM/0.22 Mbp in Deli and 0.9 cM/0.21 Mbp in La Mé. The significant degree of differentiation existing between Deli and La Mé was confirmed by the high Fst value (0.53), the pattern of correlation of SNP heterozygosity and allele frequency among populations, and the decrease of persistence of LD and of haplotype sharing among populations with increasing SNP distance. However, the level of resemblance between the two populations over short genomic distances (correlation of r values between populations >0.6 for SNPs separated by <0.5 cM or <1 kbp and percentage of common haplotypes >40% for haplotypes <3,600 bp or <0.20 cM) likely explains the superiority of GS models ignoring the parental origin of marker alleles over models taking this information into account. The two populations had low Ne (<5). Population-specific genetic maps and reference genomes are needed for future studies.

The discovery of the CRISPR-Cas genome editing technology has opened up new opportunities for crop improvement through precise genetic modifications. This new technology has shown great promise in improving crop yields, quality, and resilience to biotic and abiotic stresses. This review presents the recent advances in CRISPR-Cas technology, including new tools and techniques for precise genome editing, as well as the challenges associated with off-target effects and unintended consequences. It explores the applications of CRISPR-Cas-based genome editing in different crops, including maize, rice, wheat, and tomato, highlighting the progress achieved in improving important traits such as disease resistance, drought tolerance, and nutrient content. The regulatory concerns around CRISPR-Cas-based genome editing, as well as the ethical considerations associated with this technology are also adressed. Finally, insights into the potential impact of CRISPR-Cas-based genome editing on crop breeding and food security, and the challenges that need to be addressed to fully realize its potential are provided. This review thus highlights the potential of CRISPR-Cas-based genome editing in crop improvement and emphasizes the importance of continued research in this area for sustainable agricultural production.