Proanthocyanidins (PAs), also known as condensed tannins (CTs), are oligomers or polymers of flavan-3-ols. They have a very important role in plant-environment interactions, such as defense against herbivory and pathogens. They may also be important for light stress tolerance. In poplar, PAs can make up as much as 30% of the leaf dry weight. The synthesis of PAs in poplar was demonstrated to be inducible by both abiotic and biotic stresses. The B-ring hydroxylation pattern of flavan-3-ols directly affects the structure of PAs, and many studies have shown that B-ring hydroxylation of PAs is associated with their biological functions, including effects on leaf litter decomposition rate and anti-herbivore activity. Anthocyanins are very important colour pigments in plants, and share the intermediate leucoanthocyanidin with PAs. The role of anthocyanins in plant pollination, light stress tolerance, and seed dispersal has been well studied. A change in B-ring hydroxylation pattern can modify the colour of anthocyanins dramatically and also change their biological function. Flavonoid 3’-hydroxylase and flavonoid 3’, 5’-hydroxylase (F3’H and F3’5’H) are the two enzymes involved in determining the B-ring hydroxylation pattern of both PAs and anthocyanins. The objective of this study is to characterize the possible role of flavonoid 3’, 5’-hydroxylase in PA and anthocyanin biosynthesis in poplar. A candidate F3’5’H was identified in the Populus trichocarpa genome database based on previous expression profile experiments, and called PtF3’5’H1. The predicted protein shares high sequence similarity with previously characterized F3’5’H proteins from other plants. To test the function of PtF3’5’H1 directly, transgenic hybrid poplar plants overexpressing PtF3’5’H1 were generated. Preliminary LC-MS analysis showed that the hydroxylation pattern of the PA in the transgenic poplars was not significantly modified. Likewise, overexpression of PtF3’5’H1 in poplar did not change the overall amount of PAs. These results suggest that overexpression of PtF3’5’H1 in poplar is not sufficient to modify the B-ring hydroxylation pattern of PA, and that additional factors may be required. By contrast, the transgenic PtF3’5’H1 overexpressing poplar did show an alteration in anthocyanin profile. In leaves of transgenic poplars, several putative delphinidin derivatives were observed at greater levels than in the wild type, indicating that PtF3’5’H1 participates in the anthocyanin production in poplar. However, transiently introducing PtF3’5’H1 into Nicotiana benthamiana had no effect on the anthocyanin profile in this plant. I conclude that PtF3’5’H1 is very likely to be involved in the anthocyanin synthesis in poplar, while the function of PtF3’5’H1 in poplar PA synthesis has yet to be demonstrated. / Graduate

A study was conducted to determine if sainfoin, a condensed tannin (CT) containing legume, fed to beef cattle as hay or silage during a western Canadian winter would result in a reduction in methane (CH4) emissions without compromising animal performance. Forty yearling beef steers were fed four diets in a factorial design consisting of two legume forage species (sainfoin or alfalfa) and two preservation methods (silage or hay) over 15 weeks (wks). For each sample wk, animal weight, 24-h CH4 expiration and rumen fluid samples were obtained. Rumen methanogens were characterized using terminal restriction fragment length polymorphisms analysis. Specific bacteria were quantified with real-time polymerase chain reaction analysis. Sainfoin silage (SS) and sainfoin hay (SH) contained 11.9 and 10.5 mg g-1 of CT respectively and supported an acceptable growth rate for backgrounding steers. A decline (P < 0.05) in enteric CH4 formation could only be detected from SH-fed animals compared to alfalfa hay (AH) fed animals when CH4 was expressed as L d-1 or L kg BW-1. The rumen archaeal community structure of experimental animals remained stable regardless of diet type or sample wk. Structural carbohydrate-fermenting bacteria were suppressed in silage diets. Methanogens were less abundant in the rumen fluid samples of steers fed SS but not SH.

A study was conducted to determine if sainfoin, a condensed tannin (CT) containing legume, fed to beef cattle as hay or silage during a western Canadian winter would result in a reduction in methane (CH4) emissions without compromising animal performance. Forty yearling beef steers were fed four diets in a factorial design consisting of two legume forage species (sainfoin or alfalfa) and two preservation methods (silage or hay) over 15 weeks (wks). For each sample wk, animal weight, 24-h CH4 expiration and rumen fluid samples were obtained. Rumen methanogens were characterized using terminal restriction fragment length polymorphisms analysis. Specific bacteria were quantified with real-time polymerase chain reaction analysis. Sainfoin silage (SS) and sainfoin hay (SH) contained 11.9 and 10.5 mg g-1 of CT respectively and supported an acceptable growth rate for backgrounding steers. A decline (P < 0.05) in enteric CH4 formation could only be detected from SH-fed animals compared to alfalfa hay (AH) fed animals when CH4 was expressed as L d-1 or L kg BW-1. The rumen archaeal community structure of experimental animals remained stable regardless of diet type or sample wk. Structural carbohydrate-fermenting bacteria were suppressed in silage diets. Methanogens were less abundant in the rumen fluid samples of steers fed SS but not SH.

There is interest in increasing the content of omega-3 (n-3; e.g., linolenic acid [C18:3n3]) fatty acids and conjugated linoleic acid (CLA) in bovine milk, primarily because of their beneficial effects on human health. One strategy to alter bovine milk fatty acid composition is the dietary inclusion of flaxseed, which is a rich source of C18:3 n-3. The aim of this study was to evaluate the effects of extrusion processing of flaxseed and the inclusion of condensed tannins (CT) in a flaxseed supplement on omasal flow of nutrients, ruminal fermentation characteristics, animal performance, and milk fatty acid profiles in dairy cattle. Eight multiparous Holstein cows (712.7 ± 92.3 kg body weight; 116.5 ± 17.5 days-in-milk at the beginning of the study) were assigned to four dietary treatments in a replicated 4 x 4 Latin square design consisting of 28-d periods with 20 d of dietary adaptation. Four cows in one Latin square were ruminally-cannulated to allow ruminal and omasal sampling. Cows were fed either a control diet (CTL) or one of 3 treatment diets that consisted of the daily substitution of 3 kg (DM basis) of the CTL concentrate pellet with 3 kg (DM basis) of either a non-extruded flaxseed and pea product (55% flax¬seed, 36% peas, 8% alfalfa, 1% antioxidant; designated RAW), a extruded flaxseed and pea product (55% flaxseed, 36% peas, 8% alfalfa, 1% anti¬oxidant; designated LPR), or a extruded flaxseed and high-tannin fava bean product (55% flaxseed, 36% high-tannin faba beans, 8% alfalfa, 1% antioxidant; designated LPF). Diets were fed twice daily as total mixed rations. Omasal flow of nutrients was estimated using the omasal sampling technique using iNDF as the single indigestible marker. Dry matter intake was lower (P = 0.01) in cows fed the flaxseed diets (24.0 kg/d) compared to those fed CTL (25.9 kg/d). Milk yield was higher (P = 0.02) in cows fed the LPR diet ( 44.4 kg/d) compared to those fed the RAW diet ( 42.3 kg/d); and tended to be higher (P = 0.07) in cows fed the flaxseed diets compared to those fed the CTL diet. Milk fat yield was unaffected by dietary treatment (P = 0.94), whereas milk protein yield tended (P = 0.10) to increase in cows fed the flaxseed diets compared to those fed the CTL diet. No detrimental effects of dietary treatments on ruminal fermentation and omasal flow of microbial protein were observed. The omasal flow of C18:3 n-3 was higher in cows fed the flaxseed diets compared to those fed the CTL diet (P = 0.04), with the RAW diet (56.9 g/d) having the highest flow of C18: 3n-3 compared to the other diets (LPR = 14.0 g/d; LPF = 14.8 g/d). The omasal flow of total CLA isomers were higher (P = 0.03) in cows fed the LPF diet (6.06 g/d) compared to those fed the LPR diet (3.70 g/d). The C18:3 n-3 content in milk fat (% of fatty acid methyl esters) was higher in cows fed the LPR diet (0.950%) compared to those fed the RAW diet (0.745%). The level of total CLA isomers in milk was also higher in cows fed the LPR diet (0.845%) compared to those fed the RAW diet (0.308%). These results demonstrated that feeding extruded flaxseed products is more effective than feeding whole flaxseed at improving the fatty acid composition of milk fat without negatively impacting animal performance and ruminal fermentation; however, the inclusion of CT in the extruded flaxseed product had no additional benefit.

Amongst cereals, sorghum is one of the major sources of phenolic compounds. South African cultivars have not been profiled for their phenolic content and antioxidant activity to highlight their potential benefits. Thus, South African sorghum cultivars representing different sorghum types were evaluated for total phenolic content, condensed tannin content and antioxidant activity and the effect of cultivar on their antioxidant activity. The presence of phenolic antioxidants in the different sorghum cultivars, created an opportunity to develop a sorghum product as a vector of the antioxidants. Cookies were a product of choice due to their shelf stability and high nutrient density. Sorghum cookies were produced from 70%, 90% and 100% extraction rate flours. The effects of flour extraction rates and cultivar on the total phenolic content, condensed tannin content and antioxidant activity of the cookies were determined. Consumer sensory evaluation was used to evaluate sorghum cookie acceptability against a wheat flour cookie. Total phenolic content of the cultivars, determined by the Folin-Ciocalteu method was 0.20 to 1.42 g catechin equivalents (CE)/100 g. The total phenolic content was 3 to 7 times higher in condensed tannin cultivars than in tannin-free cultivars. Using the modified Vanillin-HCl method, condensed tannins were only measurable in the condensed tannin cultivars. They ranged between 5.16 and 8.39 g CE/100 g. Subsequently, the antioxidant activity of the condensed tannin cultivars measured by the ABTS radical scavenging assay was up to 4 times higher than in the tannin-free cultivars. The high phenolic content and antioxidant activity of condensed tannin cultivars was attributed to the contribution of condensed tannins. Therefore, condensed tannin cultivars are a major source of antioxidants compared to tannin-free cultivars. For each sorghum cultivar, cookies of 100% extraction rate flours had 2 to 3 times higher total phenolics compared to those of 70% extraction rate flours, while antioxidant activity was 2 to 10 times higher. Cookies of the condensed tannin sorghum had 2 to 5 times more phenolics compared to those of condensed tannin-free sorghum. Antioxidant activity was 145 to 227 ìMol Trolox equivalents (TE)/g in cookies of condensed tannin sorghum compared to 10 to 102 ìMol TE/g in those of condensed tannin-free sorghum. Processing sorghum flours to cookies seemed to reduce phenolic and antioxidant activity, but considering the flour component in the formula, cookie antioxidant activity was slightly higher than that of flours. The texture of all sorghum cookies was less acceptable compared to that of wheat cookies. The consumers showed a slight overall liking of the condensed tannin-free sorghum and wheat flour cookies. The cookies from condensed tannin flours were neither liked nor disliked. Since generally wheat flour is used for making cookies, the similarities in the overall liking of the condensed tannin-free sorghum cookies and the wheat flour cookies indicate strong potential of sorghum flour for cookie making. Therefore, sorghum cookies have a potential as a functional ready-to-eat snack, with target consumers such as school children in feeding schemes to improve their health and nutrition status. / Dissertation (MSc)--University of Pretoria, 2009. / Food Science / unrestricted

O presente estudo foi realizado em duas etapas com os seguintes objetivos: (i) avaliar os efeitos da suplementação com leguminosa tropical em comparação ao concentrado em gramínea tropical na ingestão de nutrientes por cordeiros; (ii) avaliar a inclusão de leguminosa tropical em pastagem de gramínea sobre o consumo de nutrientes por cordeiros recebendo polietileno glicol 4000. O delineamento experimental foi em blocos ao acaso e no segundo experimento em parcela subdividida. No primeiro estudo (capítulo III), 72 cordeiros foram alocados em 12 piquetes (0,1 ha cada) de capim Aruana (Panicum maximum cv. IZ-5) e submetidos aos tratamentos por 90 dias: 1) S0,0 – sem suplementação; 2) S1,5 - suplementação com concentrado a 1,5% de PV; 3) S2,5 -suplementação com concentrado a 2,5% PV, 4) SFG - suplementação com pastejo controlado em 0,1 ha de feijão Guandu (Cajanus cajan cv. Anão) por três horas/dia. No segundo experimento (capítulo IV), 54 cordeiros foram alocados em nove piquetes (0,2 ha cada) submetidos aos tratamentos por 84 dias: 1) Aruana – somente capim Aruana; 2) AFG - consórcio de feijão Guandu e capim Aruana, em faixa, 3) Guandu - somente feijão Guandu, cada tratamento foi subdividido em parcelas com e sem PEG (polietileno glicol 4000). No experimento 1, as variáveis de comportamento ingestivo, consumo e digestibilidade de nutrientes foram influenciadas pelos tratamentos (P < 0,05), tendo os cordeiros do grupo S2,5 apresentado melhor ingestão de nutrientes e o grupo SFG consumo intermediário. Em geral, o grupo SFG apresentou resultados semelhantes ao S1,5. No segundo experimento, as variáveis de comportamento ingestivo não foram influenciadas pelos tratamentos e pelo uso do PEG (P > 0,05). Houve interação entre os sistemas de alimentação e uso de PEG para a ingestão de nutrientes e digestibilidade (P > 0,05), com os melhores resultados para os grupos sem PEG (P < 0,05). Em geral, os animais que não receberam PEG e que foi incluído Guandu na dieta, apresentaram aumento no consumo de nutrientes. Assim, o feijão Guandu pode substituir o concentrado em nível de até 1,5% do PV como suplemento para o capim Aruana. A inclusão da leguminosa tropical com presença de taninos condensados favorece o consumo de nutrientes por cordeiros criados em pastagem tropical. / This study was performed in two stages with the following objectives: (i) to evaluate the effects of topical legume supplementation compared with the concentrate in tropical grass in the intake of nutrients by lambs; (ii) to evaluate the inclusion of tropical legume in grass pasture on intake of nutrients for lambs receiving polyethylene glycol 4000 (PEG). A randomized block design was use in the first experiment and split plot design was use in the second experiment. In the first study (Chapter III), 72 lambs were divided into 12 paddocks (0.1 ha each) of Aruana grass de (Panicum maximum cv. IZ-5) and subjected to treatments for 90 days: 1) S0,0 - only Aruana grass; 2) S1.5 - supplementation with concentrated to 1.5% of lamb BW; 3) S2.5 - supplementation with concentrated to 2.5% of lamb BW; 4) SFG – supplementation with controlled grazing on 0.1 ha of pigeon pea (Cajanus cajan cv. Anão) for three h / d. In the second study (Chapter IV), 54 lambs were divided into nine paddocks (0.2 ha each) and subjected to treatments for 84 days: 1) Aruana – only Aruana grass; 2) AFG - consortium with Aruana grass and pigeon pea; 3) Guandu – only pigeon pea, where each treatment was divided into plots with or without PEG (polyethylene glycol 4000). In the experiment 1, the ingestive behavior variables, intake and digestibility of nutrients were affect by treatments (P < 0.05) with the lambs of the group S2.5 presented better intake of nutrients and the group SFG intake intermediate. In general, the SFG group showed similar results to S1.5. In the second experiment, the ingestive behavior variables were not affected by the treatments and the use of PEG (P>0.05). There was interaction between the feeding systems and use of PEG for intake of nutrients and digestibility (P < 0.05), with the best result for the treatments without PEG (P < 0.05). In general, animals that did not receive PEG and that included pigeon pea in the diet, showed an increase in the intake of nutirents. Thus, pigeon pea can substitute the concentrate at a level of 1,5% PV as a supplement for the Aruana grass. The inclusion of the tropical legume with presence of condensed tannin favors the intake of nutrients by lambs raised in tropical pasture.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-02-13T15:14:35Z No. of bitstreams: 1 Marco Hamilton Barros da Costa Filho.pdf: 2573105 bytes, checksum: f63c114b9f31e4964f056d2413f14839 (MD5) / Made available in DSpace on 2017-02-13T15:14:35Z (GMT). No. of bitstreams: 1 Marco Hamilton Barros da Costa Filho.pdf: 2573105 bytes, checksum: f63c114b9f31e4964f056d2413f14839 (MD5) Previous issue date: 2016-07-29 / The gastrointestinal helminth infections represent one of the main causes in limiting the production of small ruminants around the world. In the search for new alternatives for effective control of these gastrointestinal nematodes, phytotherapy is presented as a promising sector in an attempt to reduce the use of chemical treatments. Making the study of plants with the potential taninífero an alternative anthelmintic control. Once these tannins identified and isolated, it becomes increasingly more practical in its real potential anthelmintic activity. In this sense, we chose species Black Jurema (Mimosa tenuiflora (Willd) Poiret), red angico (Anadenanthera macrocarpa (Benth.) Brenan) and catingueira (Poincianella pyramidalis Tul.) For chemical-bromatological characterization and quantification of the condensed tannin levels in the different fractions of the plant. These Fabaceae were collected in Caatinga area preserved the Sertânia municipality in semiarid region of Pernambuco. Leaf samples were collected with stem and bark of each species and quantification of condensed tannins in the Fabaceae study used the butanol-HCl method. Data were analyzed using descriptive statistics. In this sense, combining obtaining the purified extract of condensed tannin, held anthelmintics trials through larval development tests (TDL) in vitro fecal material collected from Saanen goats naturally infected under management of concentrations in treatments (37.5, 75, 150, 300 and 350 mg/ml) in four replicates each of purified extract of tannins, together with control treatment, positive and negative, with levamisole hydrochloride at a concentration of 7.5 mg / ml and distilled water, respectively. Mimosa tenuiflora (Willd) Poiret. He stood between native Fabaceae with the highest total concentration of tannin, in all fractions of the plant. In anthelmintic activity, significant effect, making it an excellent alternative for controlling gastrointestinal nematodes in small ruminants. / As infecções por nematódeos gastrintestinais correspondem a uma das principais causas limitantes na produção de pequenos ruminantes em todo o mundo. Na busca por novas alternativas de controle efetivo desses parasitos, a fitoterapia se apresenta como um setor promissor na tentativa de reduzir a utilização de tratamentos químicos. Tornando o estudo de plantas com potencial taninífero uma alternativa ao controle anti-helmíntico. Uma vez esses taninos identificados e isolados, torna-se cada vez mais concreto seu real potencial na atividade anti-helmíntica. Neste sentido, escolheu-se as espécies jurema preta (Mimosa tenuiflora (Willd) Poiret), angico vermelho (Anadenanthera macrocarpa (Benth.) Brenan) e catingueira (Poincianella pyramidalis Tul.) para caracterização químico-bromatológica e quantificação dos teores de taninos condensados nas diferentes frações da planta. Estas fabaceas foram coletadas em área de Caatinga preservada do município de Sertânia na região Semiárida de Pernambuco. Foram coletadas amostras de folhas com haste e casca de cada espécie, e para quantificação dos taninos condensados das fabaceas em estudo foi utilizado o método do butanol-HCl. Os valores obtidos foram analisados através de estatística descritiva. Nesse sentido, aliando a obtenção do extrato purificado de tanino condensado, realizou-se ensaios anti-helmínticos por meio de testes de desenvolvimento larval (TDL) in vitro de material fecal coletado de caprinos da raça Saanen, naturalmente infectados, sob administração das concentrações nos tratamentos (37,5; 75; 150; 300 e 350 mg/mL) em quatro repetições para cada tratamento de extrato purificado de taninos condensados, acrescidos de tratamento controle, positivo e negativo, com cloridrato de levamisol na concentração de 7,5 mg/mL e água destilada, respectivamente. A Mimosa tenuiflora (Willd) Poiret. se destacou entre as fabaceas nativas com a maior concentração de taninos totais, para todas as frações da planta. Na atividade anti-helmíntica, apresentou efeito significativo, tornando-se uma excelente alternativa no controle de nematódeos gastrintestinais em pequenos ruminantes.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-02-20T14:19:44Z No. of bitstreams: 1 Rayanne Thalita de Almeida Souza.pdf: 2435652 bytes, checksum: d445e67d5f3ef4f0224c8375ec031fcb (MD5) / Made available in DSpace on 2017-02-20T14:19:44Z (GMT). No. of bitstreams: 1 Rayanne Thalita de Almeida Souza.pdf: 2435652 bytes, checksum: d445e67d5f3ef4f0224c8375ec031fcb (MD5) Previous issue date: 2015-08-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The chemical characterization and the determination of secondary compounds in native legumes are very important for enabling better use these plants as raw material for various segments in the industry. This study aimed to characterize the chemical-bromatological bark and leaves with stems of two native legumes, quantify and characterize the fractions of condensed tannins. The species were collected: ‗Jurema preta‘ (Mimosa tenuiflora (Willd) Poiret) and ‗Angico vermelho‘ (Anadenanthera macrocarpa (Benth) Brenan.), in three cities of the northeastern semiarid: Arcoverde / PE, Patos / PB and Delmiro Gouveia / AL. The chemical analysis performed were: dry matter (DM), mineral matter (MM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF), neutral detergent insoluble nitrogen (NDIN) and acid detergent insoluble nitrogen (ADIN) and lignin digested in acid (LDA) and condensed tannins by the methodologies of HCl-Butanol and phenols by the precipitable protein (PPP). The chemical-composition data and fractions of condensed tannins were analyzed using descriptive statistics, and to compare the methods of quantification of the total condensed tannins was used the t test, at 5% significance level. They were obtained values of DM, CP and PIDA to the leaves with stems of Jurema preta e angico vermelho respectively: 435.2; 428.83 g / kg MN, 159.3; 199.6 g / kg DM, 60.1; 66.64 g / kg CP. As for total condensed tannins through the HCl-Butanol methodologies and phenols by precipitable protein, respectively, 165.32 and 258.70 g / kg DM for leaves with stems and 456.64 and 360.97 for the shells. And for the Angico vermelho: 52.62 and 162.26 g / kg DM to the leaves with stems and 168.04 and 376.03 for the shells. Concluding that a portion of the crude protein of legumes studied is unavailable because it is connected to the ADF and condensed tannins. Jurema preta was the species that showed higher total condensed tannins content. And the PPP methodology is considered the most efficient quantification of condensed tannins. / A caracterização química e a determinação de compostos secundários em leguminosas nativas são de grande importância por possibilitar um melhor uso dessas plantas como matéria prima para diversos seguimentos na indústria. A realização deste estudo teve como objetivo caracterizar químico-bromatologicamente as cascas e folhas com hastes de duas leguminosas nativas, quantificar e caracterizar as frações de taninos condensados. Foram coletadas as espécies: Jurema preta (Mimosa tenuiflora (Willd) Poiret) e Angico vermelho (Anadenanthera macrocarpa (Benth.) Brenan) em três municípios do Semiárido nordestino: Arcoverde/PE, Patos/PB e Delmiro Gouveia/AL. As análises químico-bromatológicas realizadas foram: matéria seca (MS), matéria mineral (MM), proteína bruta (PB), fibra em detergente neutro (FDN) e fibra em detergente ácido (FDA), nitrogênio insolúvel em detergente neutro (NIDN) e nitrogênio insolúvel em detergente ácido (NIDA) e lignina digerida em ácido (LDA) e de taninos condensados pelas metodologias do HCl-Butanol e a dos fenóis precipitáveis por proteína (PPP). Os dados químico-bromatológicos e frações de taninos condensados foram analisados através de estatística descritiva, e para a comparação dos métodos de quantificação dos taninos condensados totais foi utilizado o teste t, ao nível de 5% de significância. Foram obtidos valores de MS, PB e PIDA para as folhas com hastes de jurema preta e angico vermelho, respectivamente: 435,2; 428,83 g/kg MN, 159,3; 199,6 g/kg MS, 60,1; 66,64 g/kg PB. Já para taninos condensados totais através das metodologias do HCl-Butanol e Fenóis precipitáveis por proteína, respectivamente: 165,32 e 258,70 g/kg MS para folhas com hastes e 456,64 e 360,97 para as cascas. E para o Angico vermelho: 52,62 e 162,26 g/kg MS para as folhas com hastes e 168,04 e 376,03 para as cascas. Concluindo que, uma parte da proteína bruta das leguminosas estudadas está indisponível, pois se encontra ligada à FDA e taninos condensados. A Jurema preta foi a espécie que apresentou maiores teores de taninos condensados totais. E a metodologia PPP é considerada a mais eficiente na quantificação de taninos condensados.

Seed coat biochemistry and colour are highly variable in common bean (Phaseolus vulgaris) (syn. dry bean). Genetic studies of dry bean seed coat chemistry and colour have important implications in breeding efforts for improving nutrition and seed quality for consumer acceptance. The results of this thesis detail the phenotypic and genotypic characterization of seed coat post harvest darkening (PHD) in parents and progeny of crosses among them as well as the phenotypic characterization of seed coat condensed tannin (CT) accumulation in five genotypes of bean.<p> Seed coat PHD represents a problem for producers and consumers of several different market classes of dry bean. There are three post harvest darkening phenotypes: (i) non-darkening (ND), (ii) slow darkening (SD) and (iii) regular darkening (RD). The inheritance of PHD was determined by evaluating 28 populations derived from crosses between RD, SD and ND genotypes. Results suggest that at least two major, unlinked genes control the PHD trait in dry bean. Recessive epistasis with three phenotypic classes best explains the segregation ratios observed in populations from crosses between SD and ND parents. One gene, J, is responsible for whether a bean will darken and seeds of plants that are jj do not darken at all. Another gene, SD, influences the rate a seed coat will darken with seed from sdsd individuals darkening more slowly that those with the dominant SD allele. Quantitative evaluation of seed coat PHD demonstrated that there was a wide range of darkening within any given PHD phenotype. Crosses made between the ND x ND cross class resulted in F2 progeny that were all ND, however, a wide range of seed coat background colours was noted in the progeny. In several of the crosses made between ND x RD and SD x RD classes the resulting F1 progeny were all RD; however, a wide range of RD phenotypes were observed in the F2 progeny. These phenotypes are not likely due to quantitative trait loci (QTL) associated with the PHD trait, but rather a result of other chemical reactions occurring in the seed coat. Condensed tannins (CT; syn. proanthocyanidins), kaempferols, polyphenol oxidase (PPO) and possibly other compounds or enzymes may be interacting and causing this quantitative range within any given genotype as a function of environmental variability, genotype and their interaction. CT have been associated with PHD but are not responsible for the major difference between RD and SD lines. They may, however be responsible for the quantitative nature of the phenotype.<p> Condensed tannins can be harmful or beneficial to human health and the environment depending on the amount present and where it is found in the plant. Manipulating the production, accumulation and form of CT in the seed coat of dry bean would be beneficial to bean producers, consumers and breeders. This experiment quantitatively and qualitatively evaluated differences in patterns of CT accumulation in the seed coats of five genotypes of dry bean which exhibited low, medium or high concentrations of CT in their seed coats at maturity. Condensed tannin content was assessed from seeds harvested every other day from 6 40 days after flowering (DAF) using a modified BuOH-HCl assay. Results illustrated that CT accumulated as early in low CT genotypes as in high CT genotypes. CT content stabilized after 14 DAF in low CT genotypes. By contrast, CT content peaked then leveled off 30 DAF in moderate and high CT genotypes. A reduction in CT content in the higher CT lines was observed in the final stages of seed development.

Seed coat biochemistry and colour are highly variable in common bean (Phaseolus vulgaris) (syn. dry bean). Genetic studies of dry bean seed coat chemistry and colour have important implications in breeding efforts for improving nutrition and seed quality for consumer acceptance. The results of this thesis detail the phenotypic and genotypic characterization of seed coat post harvest darkening (PHD) in parents and progeny of crosses among them as well as the phenotypic characterization of seed coat condensed tannin (CT) accumulation in five genotypes of bean.<p> Seed coat PHD represents a problem for producers and consumers of several different market classes of dry bean. There are three post harvest darkening phenotypes: (i) non-darkening (ND), (ii) slow darkening (SD) and (iii) regular darkening (RD). The inheritance of PHD was determined by evaluating 28 populations derived from crosses between RD, SD and ND genotypes. Results suggest that at least two major, unlinked genes control the PHD trait in dry bean. Recessive epistasis with three phenotypic classes best explains the segregation ratios observed in populations from crosses between SD and ND parents. One gene, J, is responsible for whether a bean will darken and seeds of plants that are jj do not darken at all. Another gene, SD, influences the rate a seed coat will darken with seed from sdsd individuals darkening more slowly that those with the dominant SD allele. Quantitative evaluation of seed coat PHD demonstrated that there was a wide range of darkening within any given PHD phenotype. Crosses made between the ND x ND cross class resulted in F2 progeny that were all ND, however, a wide range of seed coat background colours was noted in the progeny. In several of the crosses made between ND x RD and SD x RD classes the resulting F1 progeny were all RD; however, a wide range of RD phenotypes were observed in the F2 progeny. These phenotypes are not likely due to quantitative trait loci (QTL) associated with the PHD trait, but rather a result of other chemical reactions occurring in the seed coat. Condensed tannins (CT; syn. proanthocyanidins), kaempferols, polyphenol oxidase (PPO) and possibly other compounds or enzymes may be interacting and causing this quantitative range within any given genotype as a function of environmental variability, genotype and their interaction. CT have been associated with PHD but are not responsible for the major difference between RD and SD lines. They may, however be responsible for the quantitative nature of the phenotype.<p> Condensed tannins can be harmful or beneficial to human health and the environment depending on the amount present and where it is found in the plant. Manipulating the production, accumulation and form of CT in the seed coat of dry bean would be beneficial to bean producers, consumers and breeders. This experiment quantitatively and qualitatively evaluated differences in patterns of CT accumulation in the seed coats of five genotypes of dry bean which exhibited low, medium or high concentrations of CT in their seed coats at maturity. Condensed tannin content was assessed from seeds harvested every other day from 6 40 days after flowering (DAF) using a modified BuOH-HCl assay. Results illustrated that CT accumulated as early in low CT genotypes as in high CT genotypes. CT content stabilized after 14 DAF in low CT genotypes. By contrast, CT content peaked then leveled off 30 DAF in moderate and high CT genotypes. A reduction in CT content in the higher CT lines was observed in the final stages of seed development.