A study of pod constriction in a peanut population with mixed wild and cultivated genetics

Abstract

AbstractWild relatives comprise a diverse genetic source from which to introduce beneficial alleles for peanut breeding. However, when using wild species for breeding, unadapted agronomic characteristics are often co‐inherited along with favorable traits. Previously, an advanced backcross population was developed from a cross between Arachis hypogaea and the wild‐derived induced allotetraploid (Arachis batizocoi × Arachis stenosperma)4x to incorporate nematode resistance genes into elite peanut. We observed additional wild alleles unintentionally inherited throughout the genome, possibly causing variation in several pod and seed characteristics. To identify the wild introgressions controlling the variation in pod constriction (PC), a critical trait for peanut's acceptability and marketability, we performed an association analysis using 419 SNPs and phenotypic data of 72 BC3F2/3 families. An introgression on the top of chromosome B08 (pod constriction‐quantitative trait locus [PC‐QTL], 3.7 Mbp) derived from A. batizocoi was found to be controlling 47.3% of the PC variation. To confirm the PC‐QTL, six BC3F4 families harboring the wild loci in a homozygous or heterozygous state were selected and used for segregation analysis. All progenies from the backcross families carrying the homozygous allele had severely constricted pods, whereas progenies from families with the heterozygous allele were segregated for PC. Finally, analyses using end‐point genotyping with four linked SNP assays confirmed the association of the PC‐QTL with PC. The present work studied PC and developed DNA markers to assist the selection against constricted pods while retaining the new and beneficial wild‐derived genes.