Tryptophan and methionine levels in quality protein maize breeding germplasm

dc.contributor.author Scott, M. P.
dc.contributor.author Bhatnagar, S.
dc.contributor.author Scott, Marvin
dc.contributor.author Betran, J.
dc.contributor.department Agronomy
dc.date 2018-02-18T15:33:38.000
dc.date.accessioned 2020-06-29T23:03:06Z
dc.date.available 2020-06-29T23:03:06Z
dc.date.issued 2004-01-01
dc.description.abstract <p>Because maize (Lea mays L.) is often used either as food for humans or as feed for monogastric animals, essential amino acid levels are important. Maize kernels containing the opaque-2 (o2) mutation have improved amino acid balance and poor agronomic qualities including opaque kernels that are soft and susceptible to mechanical and biological damage. Quality Protein Maize (QPM) developed through plant breeding has improved amino acid balance conferred by the opaque-2 (o2) mutation, but lacks the agronomic deficiencies normally associated with this mutation. To characterize the amino acid balance in QPM breeding germplasm, we determined the levels of nutritionally limiting amino acids tryptophan and methionine. Tryptophan levels were negatively correlated with endosperm translucence, a measure of kernel hardness suggesting the process of selection for hard-kernels reduces tryptophan levels. On average, germplasm containing the o2/ o2 mutation had lower methionine levels than 02/ 02 germ plasm regardless of kernel hardness, suggesting methionine levels could be reduced by the o2/ o2 mutation. A series of inbred lines was test-crossed to the o2/o2 soft endosperm inbred line Tx804. The predictive value of the characteristics of the inbred line for the characteristics of the hybrids was examined. The amino acid levels of the inbred lines were significantly correlated with those of the hybrids, although the predictive value was low (1{2 = 0.13 and 0.27 for methionine and t1yptophan, respectively). The reduction in tryptophan during conversion to the hard-kernel phenotype and the reduction in methionine in o2 germplasm both reduce the nutritional value of QPM. It may be possible to correct these deficiencies by breeding and selection for levels of tryptophan and methionine.</p>
dc.description.comments <p>This article is published as Scott, M. P., Sandeep Bhatnagar, and Javier Betran. "Tryptophan and methionine levels in quality protein maize breeding germplasm." <em>Maydica</em> 49 (2004): 303-311.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/agron_pubs/169/
dc.identifier.articleid 1175
dc.identifier.contextkey 10441575
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath agron_pubs/169
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/4498
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/agron_pubs/169/2004_Scott_TryptophanMethionine.pdf|||Fri Jan 14 21:07:45 UTC 2022
dc.subject.disciplines Agricultural Science
dc.subject.disciplines Agronomy and Crop Sciences
dc.subject.disciplines Plant Breeding and Genetics
dc.subject.keywords Tryptophan
dc.subject.keywords Methionine
dc.subject.keywords Quality protein maize
dc.title Tryptophan and methionine levels in quality protein maize breeding germplasm
dc.type article
dc.type.genre article
dspace.entity.type Publication
relation.isAuthorOfPublication 97acee5f-1291-4c27-8929-a8e1617c411d
relation.isOrgUnitOfPublication fdd5c06c-bdbe-469c-a38e-51e664fece7a
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