Inheritance of the Absence of the Kunitz Trypsin Inhibitor in Seed Protein of Soybeans¹

Abstract

Soybean [ Glycine max (L.) Merrill] seds from reciprocal crosses of ‘Amsoy 71’ and P.I. 157440, reciprocal crosses of P.I. 196172 and P.I. 157440, and the cross P.I. 157440 ✕ ‘Jefferson’ were analyzed using polyacrylamide gel electrophoresis to study the inheritance of the absence of the Kunitz trypsin inhibitor (SBTI‐A 2 ). Amsoy 71 has the SBTI‐A 2 , at Rf 0.79 ( Ti a ), Jefferson at Rf 0.75 ( Ti b ), P.I. 196172 at Rf 0.83 ( Ti c ), and P.I. 157440 lacks the SBTI‐A 2 , band. The F 2 and F 3 data establish that the absence of the SBTI‐A 2 , band is inherited as a recessive to the codominant alleles Ti a , Ti b , and Ti c . The allele for absence of the SBTI‐A 2 band is designated ti . The homozygous recessive condition ( ti ti ) results in the lack of SBTI‐A 2 . The lack of the SBTI‐A 2 , protein was confirmed using spectrophometric assay procedures.