Tilling by sequencing (TbS) and association analysis in EMS induced M2 population of groundnut TMV (Gn) 13 for higher oleic acid content

The present investigation was carried out in ground nut TMV (Gn) 13 to increase its oleic acid content. Its seeds were treated with EMS (ethyl methane sulfonate) at different concentration of 10 mM, 20 mM, 30 mM, 40 mM and 50 mM. Probit analysis conducted in the M1 generation revealed an LD50 value of 39 mM. Consequently, the lower (30 mM) and upper (50 mM) limits of the LD50 were forwarded to the M2 generation. Allele-specific primers were used for screening and analysis through TILLING (Target Induced Local Lesions in Genomes), utilizing Sanger sequencing. The analysis revealed mutations in the ahFAD2A and ahFAD2B genes, which are responsible for the conversion of oleic acid to linoleic acid, resulting in improved oleic acid levels in 7 putative mutants. Additional analyses, such as correlation and path analysis, were conducted using 16 yield-contributing traits. The number of pods, pod width, number of primary branches and number of secondary branches showed a positive correlation with pod yield per plant. It was observed that oleic acid had a negative correlation with linoleic acid content. Choosing traits that have a stronger correlation with pod yield per plant would speed up the improvement program for groundnuts. Therefore, potential mutants in M2 with improved pod yield traits, characterized by high oleic and low linolenic levels, would be selected for advancement to the M3 generation.