Classical and Molecular Approaches for Mapping of Genes and Quantitative Trait Loci in Peanut

Abstract

Advances in availability of genomic resources coupled with genetic resources have accelerated the process of developing better understanding of cytogenetics and genetics of peanut using modern technologies. The cytogenetic studies provided greater insights on chromosomal structures and behaviour of different Arachis species along with their genetic relationship with each other. Researchers are moving faster now in using single nucleotide polymorphism (SNP) markers in their genetic studies as simple sequence repeats (SSRs) did not provide optimum genome density for genetic mapping studies in peanut. Due to availability of reference genome of diploid progenitors, resequencing of some genotypes and soon to be available tetraploid genome, a high-density genotyping array with 58 K SNPs is now available for conducting high-resolution mapping in peanut. ICRISAT has developed next generation genetic mapping populations such as multi-parent advanced generation intercross (MAGIC) and nested association mapping (NAM) populations for conducting high-resolution trait mapping for multiple traits in one go. Affordability of sequencing also encouraged initiation of sequence-based trait mapping such as QTL-seq for dissecting foliar disease resistance trait. Few successful examples are available in peanut regarding development of diagnostic markers and their deployment in breeding to develop improved genotypes, which may see a significant increase in coming years for developing appropriate genomics tools for breeding in peanut.