Show simple item record

dc.contributor.advisorAwika, Joseph M
dc.creatorGawde, Archana Jairam
dc.date.accessioned2013-10-03T15:12:57Z
dc.date.available2015-05-01T05:57:10Z
dc.date.created2013-05
dc.date.issued2013-04-30
dc.date.submittedMay 2013
dc.identifier.urihttp://hdl.handle.net/1969.1/149617
dc.description.abstractOne of the many ways to address health, obesity and hunger issues is genetic bio-fortification, a strategy of breeding or transforming staple crops with micronutrients and vitamins. This dissertation details efforts to bio-fortify bioactive compounds (phenols, antioxidants, condensed tannins, flavonoids and anthocyanins) in Vigna unguiculata, a staple legume grain crop. Approaches included screening of genetic variation in polyphenolic compositions to identify potential varieties and phenotypes, evaluating the impact of environment (drought stress) on these compositions and elucidating the underlying genetics of their inheritance. Our screening showed significant diversity among genotypes for phenols (2.05 –15.48 mg GAE/g), condensed tannin (0.05 -15.29 mg CE/g) and antioxidant activity (4.0 -201.8 µM TE/g). The highest levels of phenols and antioxidant activity were observed in genotypes with light brown, black and red seed coat color, and those with smooth texture and medium maturity (70-90 days). Red and black phenotypes showed the highest content of flavan-3-ols, flavonols and phenolic acids among all color groups, with values of 169 µg CE/g, 26.17 µg QHE/g, 27.14 µg GAE/g for red and 281 µg CE/g, 23 µg QHE/g and 25 GAE/g for black phenotypes. When studying the impact of drought stress, genotypeXtreatment and treatmentXyear interactions for bioactive compounds were significant when tested under irrigated and drought stress conditions. Anthocyanins showed a 14 % decrease under drought stress. The genotypes that were stable to drought stress are favorable for breeding programs in preparation towards climate change. An FTNIR method was established for high-throughput, non-destructive quantification of bioactive compounds. This was used in inheritance studies of bioactive compounds. Phenols, condensed tannins and flavonoids showed heterosis in F1 and exhibit transgressive segregation in F2 populations. The information presented in this manuscript will be useful for nutritional improvement of cowpeas, where potential genotypes and phenotypes with health benefits offered by enhanced contents of bioactive compounds can be improved further upon.en
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.subjectphenolsen
dc.subjecttanninsen
dc.subjectflavonoidsen
dc.subjectanthocyaninsen
dc.subjectFTNIRen
dc.titleBreeding for Bioactive Compounds in Vigna Unguiculata L. (WALP.)en
dc.typeThesisen
thesis.degree.departmentSoil and Crop Sciencesen
thesis.degree.disciplineMolecular and Environmental Plant Sciencesen
thesis.degree.grantorTexas A&M Universityen
thesis.degree.nameDoctor of Philosophyen
thesis.degree.levelDoctoralen
dc.contributor.committeeMemberHays, Dirk B
dc.contributor.committeeMemberDuncan, Robert W
dc.contributor.committeeMemberMurray, Seth C
dc.contributor.committeeMemberSingh, Bir B
dc.type.materialtexten
dc.date.updated2013-10-03T15:12:57Z
local.embargo.terms2015-05-01


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record