Agronomic performance of soybean with seed lipoxygenase nulls and low linolenic acid content

Oxidation of linolenic acid (LA) is catalyzed by lipoxygenase (LX) and is associated with off-flavours of soybean [Glycine max (L.) Merrill] products. Low LA (LLA, <50 g kg-1 LA) and LX triple null (3lx) soybean lines have been developed to improve the oxidative stability of soybean oil and reduce off-flavours. The objective of this study was to evaluate the agronomic performance of recombinant inbred line (RIL) soybean population derived from the reciprocal crosses between a LLA line, RG10, and a 3lx line, OX948 and low LA, LX triple null (LLA.3lx) lines selected from these populations. Evaluation of RIL populations for seed and agronomic characteristics at three Ontario locations (Harrow, Ridgetown and Woodslee) in 2000 and 2001 indicated that reduction of LA and removal of seed LX did not cause any obvious detrimental effects agronomic traits including yield. Several RILs that combine LLA content (<30 g kg-1) with 3lx were obtained from these crosses and evaluated for a number of seed and agronomic traits at four Ontario locations (Harrow, Ridgetown, Woodslee and Woodstock) in 2001. The LLA.3lx lines had higher than average seed weight and protein content, but were 21 to 31% lower yielding than typical cultivars for these regions. Compared with parental lines, the LLA.3lx lines were 5 to 18% lower yielding. However, comparisons of LLA.3lx lines with lines combining high linolenic acid and all three seed lipoxygenases (HLA.3LX) indicated no yield difference between the two groups of lines in these populations. The results suggest that it should be possible to use this novel germplasm to develop competitive soybean cultivars that are resistant to oxidative degradation. Key words: Soybean, lipoxygenase null, low linolenic acid, performance