Biochemical screening for trypsin inhibitor factors and morphomolecular characterization of soybean (Glycine max L. Merr.)

A set of 101 diverse soybean genotypes were biochemically analyzed for trypsin inhibitor (TI) contents, and were characterized with morphological and molecular markers. The TI content in the seeds ranged from 14.65 to 175.52 mg g⁻¹ soymeal. The Indian soybean varieties were found to contain higher amount of TI (58.79–126.78 mg g⁻¹ soymeal) while PI542044, an exotic germplasm was found to contain the least (14.65 mg g⁻¹ soymeal). Morphological characterization with 16 qualitative and quantitative traits revealed significant variations and grouped the genotypes in to three major groups with overall mean dissimilarity value of 0.30. Genetic diversity study conducted with 100 simple sequence repeat (SSR) markers detected higher level of polymorphism (71%). Of the total 221 alleles amplified, 65 were rare (frequency <0.2). The mean polymorphism information content (PIC) of the markers was 0.27 while the value for gene diversity was 0.44. UPGMA-based cluster analysis grouped the genotypes into four major clusters of which I, II and III were occupied by genotypes containing higher and moderate level of TI. PI542044, which was free from Kunitz trypsin inhibitor (KTI), grouped singly. Such genotype would be suitable for use in breeding program directed towards development of varieties with zero KTI.