U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Corn Insects and Crop Genetics Research: Ames, IA
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    Careers


        


                    Database Projects
                        MaizeGDB
                                    SoyBase
                                    PeanutBase
                                    Legume Information System
                                    Maize Newsletter
                                    Maize Mutant Phenotypes
                                    Maize Genetics Conference
                                    Shiny Soybase CNV
                                    Shiny Soybase SNP
                                    Common Bean and Alfalfa - PvGEA
                                    Common Bean and Alfalfa - AGEDSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Midwest Area Ames, Iowa Corn Insects and Crop Genetics Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            GUTIERREZ-ROJAS, ANDRES - TEXAS A&Mitem
                                            Scott, Marvinitem
                                            LEYVA, OTTO - TEXAS A&Mitem
                                            MENZ, MONICA - TEXAS A&Mitem
                                            BETRAN, JAVIER - TEXAS A&M
  Submitted to: Crop Science
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 8/3/2007
                                    Publication  Date: 9/23/2008
                                    Citation: Gutierrez-Rojas, A., Scott, M.P., Leyva, O.R., Menz, M., Betran, J. 2008. Phenotypic Characterization of Quality Protein Maize (QPM) Endosperm Modification and Amino Acid Contents in a Segregating Recombinant Inbred Population. Crop Science. 48:1714-1722. Interpretive Summary: One of the main nutritional limitations of corn is it's content of the essential amino acids lysine trypothpan and methionine.  A consequence of this limitation to meat producers is that they have to supplement animal feed with expensive sources of these amino acids.  Genetic improvements to maize can be made to increase the levels of these limiting nutrients.  One approach to doing this is with the mutation opaque2 (o2).  This mutation increases the nutritional value of corn, but decreases grain qulaity.  In order to breed for improved corn containing the o2 mutation, it is necessary to understand the relationship between nutritional quality, grain quality and the environment.  In this paper, we characterized these relationships using a collection of o2 maize lines and evaluating their amino acid content and grain quality traits in several environments.  We observed negative correlations between amino acid content and most grain quality triats.  This information will allow breeders to design more efficient selection protocols that will reduce the time required to develop lines with improved nutritional quality.  The ultimate impact of this work will be to decrease the cost of meat production.
                                Technical Abstract: The protein quality of maize can be improved by replacing normal Opaque2 alleles with non-functional recessive alleles (o2). Homozygous o2 kernels have increased levels of lysine and tryptophan. Unfortunately, the associated soft texture of the o2 kernels causes poor yield and susceptibility to diseases and insects. Breeding programs have restored the desirable ratio of hard vs. soft endosperm in o2 genotypes developing modified endosperm versions called Quality Protein Maize (QPM). QPM germplasm, developed mostly by the International Maize and Wheat Improvement Center, is currently utilized in breeding programs worldwide and has been demonstrated to be competitive in yield trials when compared to local checks. To contribute to an increased understanding of the genetics of endosperm modification, a population of 146 recombinant inbred lines (S5 to S7) derived from a cross between the o2 inbred line B73o2 and the QPM inbred line CML161 was evaluated in two Texas locations from 2004 to 2006. Four traits related to endosperm texture showed significant effect of the inbred lines, high heritability estimates (h2 = 0.83- 0.94) and high genetic correlations (GC) among them (GC= 0.81-1.0). Relative content of the essential amino acids lysine, tryptophan and methionine also showed significant effects of the lines, genetic correlations GC = 0.63-0.68, and heritabilities h2 = 0.71-0.80. Negative correlation was observed between endosperm texture traits and amino acid content. Nevertheless, favorable responses to selection would be expected for both traits if selection strategies include monitoring of both endosperm texture modification and relative content of the essential amino acids.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov