Genetic Elimination of Off-Flavour Generating Lipoxygenase-2 Gene of Soybean through Marker Assisted Backcrossing and Its Effect on Seed Longevity

Lipoxygenase-2 present in soybean seeds is the prime contributor to off-flavour generated during the processing of soy products. Genetic elimination of this undesirable component is important as the heat inactivation not only incurs extra cost but also affects the protein solubility. The present study was aimed at eliminating lipoxygenase-2 from cultivar ‘JS97-52’ through marker assisted introgression of null allele of Lox2 from PI596540 (lox2lox2). Foreground selection in BC1F1, BC2F1 and BC3F1 of the cross ‘JS97-52’ × PI596540 was carried out using lox2 specific marker, while lox2 specific marker in combination with SSR marker Satt656 tightly linked with Lox2 locus was employed for identification of homozygous recessive plants (lox2lox2) in BC2F2 and BC3F2. Background selection performed using 150 polymorphic markers resulted in development of 12 Lox2-free soybean lines (BC3F2:3 seeds) exhibiting recurrent parent genome content in the range of 97.66-98.66%. Qualitative and quantitative assays confirmed the absence of Lox2 in introgressed lines (ILs). The ILs were at par in days-to-flowering, days-to-maturity,100-seeds weight, yield and protein content with the recurrent parent but showed significant improvement in seed longevity over the latter.