title: Improving hybrid seed production in corn with glyphosate-mediated male sterility.
abstract: BACKGROUND
  Hybrid corn varieties exhibit benefits associated with heterosis and account for most of the corn acreage in the USA. Hybrid seed corn is produced by crossing a female parent which is male-sterile and therefore incapable of self-pollination with a male parent as the pollen donor. The majority of hybrid seed corn is produced by mechanical detasseling which involves physically removing the tassel, a process that is laborious and costly.
  
  
  RESULTS
  Glyphosate-resistant corn was developed via expression of a glyphosate insensitive 5-enolpyruvyl-shikimate 3-phosphate synthase enzyme (CP4-EPSPS). Experimentation with molecular expression elements resulted in selective reduction of CP4-EPSPS expression in male reproductive tissues. The resulting plant demonstrated sterile tassel following glyphosate application with little to no injury to the rest of the plant. Using (14)C-glyphosate as a marker, we also examined the translocation of glyphosate to the tassel via spray application in a track sprayer to simulate field application. The results allowed optimization of spray parameters such as dose, spray timing and target to maximize tassel delivery of glyphosate for efficient sterilization.
  
  
  CONCLUSIONS
  The Roundup hybridization system (RHS) is a novel process for hybrid seed production based on glyphosate-mediated male sterility. RHS replaces mechanical detasseling with glyphosate spray and greatly simplifies the process of hybrid seed corn production.
authors: Monsanto Co., 800 N. Lindbergh Blvd, St., Louis, MO, 63167, USA.
authors: Paul C C
authors: PC
authors: Feng
authors: Youlin
authors: Y
authors: Qi
authors: Tommy
authors: T
authors: Chiu
authors: Martin A
authors: MA
authors: Stoecker
authors: Christopher L
authors: CL
authors: Schuster
authors: Scott C
authors: SC
authors: Johnson
authors: Augustine E
authors: AE
authors: Fonseca
authors: Jintai
authors: J
authors: Huang
mesh_terms: D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D005818:Genetic Engineering / Q000379:methods*; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006540:Herbicides / Q000494:pharmacology; D006824:Hybridization, Genetic / Q000187:drug effects*; D051479:Plant Infertility / Q000187:drug effects* / Q000235:genetics; D030821:Plants, Genetically Modified; D021381:Protein Transport / Q000187:drug effects; D012639:Seeds / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D013997:Time Factors; D003313:Zea mays / Q000187:drug effects / Q000235:genetics* / Q000502:physiology*; D000097797:Glyphosate
chemical_list: D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase; D005998:Glycine; D006540:Herbicides; D000097797:Glyphosate
keywords: Roundup; corn; glyphosate; hybrid seed; male sterility