title: Introgression of null allele of Kunitz trypsin inhibitor through marker-assisted backcross breeding in soybean (Glycine max L. Merr.).
abstract: Presence of Kunitz trypsin inhibitor (KTI) in soybean seeds necessitates pre-heat treatment of the soy-flour for its inactivation before using it in food and feed products. The heat treatment not only enhances processing costs of the soy-based foods and feeds but also affects seed-protein quality and solubility. Genetic elimination of KTI is an important and effective approach. Therefore, molecular marker-assisted backcross breeding (MABB) approach was adopted for genetic elimination of KTI from two popular soybean genotypes, DS9712 and DS9814. PI542044, an exotic germplasm line was used as donor of the kti allele which inhibits functional KTI peptide production.
  
  
  
  Foreground selection for the kti allele was performed with three closely linked SSR markers while background selection was done with 93 polymorphic SSR markers. Plants in the BC1F1 generation were found to recover 70.4-87.63 % and 60.26-73.78 % of the recurrent parent genome (RPG) of DS9712 and DS9814, respectively. Similarly, selected plants in the BC2F1 generation had 93.01-98.92 % and 83.3-91.67 % recovery of their respective RPGs. Recombinant selection was performed so as to identify plants with minimal linkage drag. Biochemical analysis of the seeds of the selected plants (ktikti) confirmed absence of KTI peptides in the seeds. Phenotypically, the selected plants were comparable to the respective recurrent parent in yield and other traits.
  
  
  
  MABB approach helped in speedy development of 6 KTI free breeding lines of soybean. Such lines will be suitable for the farmers and the soybean industries to use in production of soy-based foods and feeds without pre-heat treatment of the soy-flour. It would contribute towards wider acceptability of soy-based foods and feeds.
authors.affiliation: ICAR- Indian Institute of Soybean Research, Indore, MP, India.|Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.
authors.forename: Shivakumar
authors.initials: S
authors.lastname: Maranna
authors.affiliation: Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.
authors.forename: Khushbu
authors.initials: K
authors.lastname: Verma
authors.affiliation: Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India. atalukdar@iari.res.in.
authors.forename: Akshay
authors.initials: A
authors.lastname: Talukdar
authors.affiliation: Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.
authors.forename: Sanjay Kumar
authors.initials: SK
authors.lastname: Lal
authors.affiliation: Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.
authors.forename: Anil
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.
authors.forename: Keya
authors.initials: K
authors.lastname: Mukherjee
mesh_terms: D000483:Alleles; D017353:Gene Deletion; D007178:Inbreeding / Q000379:methods*; D018895:Microsatellite Repeats; D000069600:Plant Breeding; D012641:Selection, Genetic; D013025:Glycine max / Q000235:genetics*; D014360:Trypsin Inhibitor, Kunitz Soybean / Q000235:genetics*
chemical_list: D014360:Trypsin Inhibitor, Kunitz Soybean
keywords: Foreground and background selection; Kunitz trypsin inhibitor; Marker-assisted backcross breeding; Null allele; SSR markers