Enhancing oleic acid content in two commercially released peanut varieties through marker-assisted backcross breeding

Two elite cultivars of peanut (Arachis hypogaea L.), GPBD 4 and G 2-52, with high productivity, oil content, resistance to late leaf spot [Phaeoisariopsis personata (Berk. & Curt) V. Arx.] (LLS) and rust (Puccinia arachidis Speg.) diseases were improved for oleic acid content using marker-assisted backcrossing. Since both the recurrent parents already possessed the mutant allele at AhFAD2A, only mutant allele at AhFAD2B was transferred from the donor 'SunOleic 95R' (oleate of 80.6%). Three rounds of backcrossing with foreground selection using allele-specific polymerase chain reaction (PCR) and Kompetitive allele-specific PCR (KASP) assay identified a large number of plants homozygous for the mutant allele at AhFAD2B in BCnF2 generations. Evaluation of the advanced generations could identify six and 10 lines with significantly higher oleate than GPBD 4 and G 2-52, respectively. Considering the yield, shelling percentage, oil, and oleate content, the most promising lines HOBC(2)GPS_7 and HOBC(2)G2S_5 were selected with 112 and 142% oleate recovery over GPBD 4 and G 2-52, respectively. Double digest restriction-site-associated DNA sequencing of these superior lines showed background genome recovery of 77.5 and 69.0%, respectively. These advanced breeding lines with high oleate (similar to 80%), resistance to LLS and rust and high productivity are under further trials for possible release as varieties for commercial cultivation.

Automated summary

Two elite cultivars of peanut were improved for oleic acid content using marker-assisted backcrossing, resulting in the development of high oleic, high-yielding, disease-resistant new varieties. The most promising breeding lines are currently undergoing further trials for potential release as commercial cultivation varieties.