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The peanut rich in oleic acid in seed oil, also known as high oleic peanut, renders its products superior in human healthy diet, long shelf life and high oxidative stability in food and oil processing. High oleic peanut varieties in China are derived from a handful of high oleic donors with limited genetic background. Improvement of high oleic peanut cultivars by integrating key target traits is crucial for both food security and germplasm enhancement. Several superior high oleic peanut lines have been developed by marker assisted backcrossing in our breeding program. The objective of present study is to characterize bacterial wilt disease resistance and yield related traits in these novel peanut lines. The two-year disease nursery survival rates were used as an indicator for bacterial wilt resistance, and the diagnostic markers identified by QTL mapping were used for molecular verification. Genetic background of high oleic peanut lines was estimated by 40 K genotyping by target sequencing (GBTS) SNP panel. Preliminary and regional yield tests were performed for selected breeding lines in 2021. As a result, an elite high oleic peanut accession Yuhua183 was identified, inheriting the superior characteristics of its recurrent parent such as resistance to bacterial wilt, high shelling percentage and early maturity. The development of Yuhua183 broadened the genetic background of high oleic peanut germplasm, providing valuable genetic resources for peanut breeding and further utilization. [ABSTRACT FROM AUTHOR]

Key message: A major QTL, qBWA12, was fine mapped to a 216.68 kb physical region, and A12.4097252 was identified as a useful KASP marker for breeding peanut varieties resistant to bacterial wilt. Bacterial wilt, caused by Ralstonia solanacearum, is a major disease detrimental to peanut production in China. Breeding disease-resistant peanut varieties is the most economical and effective way to prevent the disease and yield loss. Fine mapping the QTLs for bacterial wilt resistance is critical for the marker-assisted breeding of disease-resistant varieties. A recombinant inbred population comprising 521 lines was used to construct a high-density genetic linkage map and to identify QTLs for bacterial wilt resistance following restriction-site-associated DNA sequencing. The genetic map, which included 5120 SNP markers, covered a length of 3179 cM with an average marker distance of 0.6 cM. Four QTLs for bacterial wilt resistance were mapped on four chromosomes. One major QTL, qBWA12, with LOD score of 32.8–66.0 and PVE of 31.2–44.8%, was stably detected in all four development stages investigated over the 3 trial years. Additionally, qBWA12 spanned a 2.7 cM region, corresponding to approximately 0.4 Mb and was fine mapped to a 216.7 kb region by applying KASP markers that were polymorphic between the two parents based on whole-genome resequencing data. In a large collection of breeding and germplasm lines, it was proved that KASP marker A12.4097252 can be applied for the marker-assisted breeding to develop peanut varieties resistant to bacterial wilt. Of the 19 candidate genes in the region covered by qBWA12, nine NBS-LRR genes should be further investigated regarding their potential contribution to the resistance of peanut against bacterial wilt. [ABSTRACT FROM AUTHOR]