Seed and agronomic QTL in low linolenic acid, lipoxygenase-free soybean (<i>Glycine max</i>(L.) Merrill) germplasm

TLDR

Linolenic acid and seed lipoxygenases cause off‑flavours in soybean products. The study genotyped 5 F5 recombinant inbred lines from a cross between a low‑linolenic‑acid line (RG10) and a lipoxygenase‑free line (OX948) using SSR, RAPD, STS, and CAPS markers and evaluated seed and agronomic traits across three Ontario locations over two years. A composite map of 120 markers spanning 1247.5 cM across 18 linkage groups was constructed, locating lipoxygenase genes L‑1 and L‑2 as single major genes on LG G13‑F, L‑3 on LG G11‑E, and.

Abstract

Linolenic acid and seed lipoxygenases are associated with off flavours in soybean products. F 5 recombinant inbred lines (RILs) from a cross between a low linolenic acid line (RG10) and a seed lipoxygenase-free line (OX948) were genotyped for simple sequence repeats (SSR), random amplified polymorphic DNA (RAPD), sequence-tagged sites (STS), and cleaved amplified polymorphic sequence (CAPS) markers and evaluated for seed and agronomic traits at 3 Ontario locations in 2 years. One hundred twenty markers covering 1247.5 cM were mapped to 18 linkage groups (LGs) in the soybean composite genetic map. Seed lipoxygenases L-1 and L-2 mapped as single major genes to the same location on LG G13-F. L-3 mapped to LG G11-E. This is the first report of a map position for L-3. A major quantitative trait locus (QTL) associated with reduced linolenic acid content was identified on LG G3-B2. QTLs for 12 additional seed and agronomic traits were detected. Linolenic acid content, linoleic acid content, yield, seed mass, protein content, and plant height QTL were present in at least 4 of 6 environments. Three to 8 QTLs per trait were detected that accounted for up to 78% of total variation. Linolenic acid and lipoxygenase loci did not overlap yield QTL, suggesting that it should be possible to develop high-yielding lines resistant to oxidative degradation by marker-assisted selection (MAS).