Identification of low lectin mutants in soybean

Lectin is one of the known antinutritional factors that deteriorate the soybean protein quality and development of cultivars with low lectin content will help to improve nutritional quality of soybean Glycine max (L.) Merrill]. Therefore, attempts were made to induce mutations for low lectin content in the cultivar ‘MACS 450’. Soybean cultivar ‘MACS 450’ was subjected to combination treatments of γ‐rays and ethyl methane sulphonate (EMS) with an objective to induce variability for low lectin content. The treatments of different combinations of γ‐rays and EMS were 50 Gy + 0.2% EMS, 50 Gy + 0.4% EMS, 100 Gy + 0.2% EMS and 100 Gy + 0.4% EMS. Of the 3200 treated M₁ seeds sown, 16 400 M₂ plants were raised. In M_2, 72 plants were identified for low lectin content <40 × 10⁵ haemagglutination unit (HAU)/mg] and were carried up to M₅ generation. In M₅ generation, lectin content in ‘MACS 450’ was 39.23 to 50.0 × 10⁵ HAU/mg, and was compared with the nine true breeding lines identified having low lectin content, ranging from 2.3 × 10⁵ to 27.46 × 10⁵ HAU/mg. Three mutants were found to possess very low lectin content (ranging from 2.0 × 10⁵ to 3.0 × 10⁵ HAU/mg). Thus, the identified mutant lines with low lectin content will greatly improve soybean protein quality, thereby reducing financial burden on the soybean industry for processing soybean meal and also making it suitable for human consumption. All the mutants showed normal seed development, having soluble protein content similar or higher than that in the parent (32.0 mg/ml). This indicates that the change in lectin content does not have any negative impact on the plant growth and protein content.