When testing nine different sunflower cultivars in 32 South African environments (location x year), an Additive Main Effects and Multiplicative Interaction analysis (AMMI) identified sizeable genotype by environment (GxE) interaction. The first two Interaction Principal Components Axes (IPCA1 and IPCA2) were highly significant (p<0.001), but all the factors responsible for the GxE interaction could not be identified, as the causes of interaction seems to be of complex nature. IPCA1 captured 34% of the interaction SS with only 15.3% of the degrees of freedom, while IPCA2 captured 22.5% of the interaction SS with 14.5% of the degrees of freedom. This indicates that the AMMI2 model fits the data well and is parsimonious. Both cultivars and environments grouped together in quadrants according to their length of season when their respective IPCA1 and IPCA2 scores were plotted against each other. Environments from the warmer dry Western and Northern regions, including the Dry Highveld Grassland, Northern Arid and Central Bushveld, grouped in opposite quadrants, 1 and 3, while environments from the cooler moist Eastern regions, including the Moist Highveld Grassland grouped in opposite quadrants, 2 and 4. The factors responsible for the division between quadrants 1 and 3, as well as those responsible for the division between quadrants 2 and 4 could not be identified. The long-season cultivars were better adapted to the Northern and Western environments, while the medium-season cultivars were better adapted to the Eastern environments. Each quadrant was dominated by a different cultivar. Because the environments and cultivars could not be sufficiently described according to the factors responsible for the observed GxE interaction, cultivars can not be advised for specific environments. It is therefore presently recommended that cultivars which are more widely adapted to South African conditions, be selected. / Dissertation (MSc (Genetics))--University of Pretoria, 2004. / Genetics / unrestricted

The low and varying protein content and high crude fibre content of sunflower oil cake produced from sunflower seed create problems for the South African oil expelling industry. This prompted research into factors that may affect the seed quality for processing purposes. The seed quality characteristics are the seed oil and protein contents and the hullability. Analysis of the kernel-rich fraction produced after dehulling gives an indication of the potential oil yield, oil cake yield and oil cake protein and crude fibre contents and thus the processed value. Seed hullability and potential losses of oil and protein were affected by seed moisture content and seed size. Drying seed resulted in increased hullability, and sifting it into size classes proved to be a mechanism for differentiating in terms of oil cake quality. The effects of cultivar, environment and selected environmental variables on seed yield and processing quality were investigated by means of field trials. Seed yield and quality were more affected by environment than by cultivar. Seed size and hullability, and as a result also the protein content of the potential oil cake, were affected by plant population, with lower populations associated with better quality. Increased nitrogen application improved seed yield and seed protein content but lowered seed oil content, with no effect on hullability. Boron fertilisation improved seed yield in one trial but suppressed yield in a second trial. Hullability declined in one trial due to boron fertilisation. A mild water stress during the grain-filling stage reduced seed yield by 23% and hullability by 14%. Optimising the seed oil:seed protein ration through breeding may be the most advisable option for improving seed quality for processing. Due to the need for a seed grading system based on seed quality, regression analyses between easily measurable seed characteristics and seed quality parameters were done. The relatively low mean deviation between measured and predicted values indicate that seed oil content, protein content and hullability can be estimated with reasonable accuracy. These relationships must still be validated. / Dissertation (PhD (Plant Production: Agronomy))--University of Pretoria, 2002. / Plant Production and Soil Science / unrestricted

Made available in DSpace on 2016-08-12T19:15:25Z (GMT). No. of bitstreams: 1 YuriLM_DISSERT.pdf: 1834297 bytes, checksum: 18de998f0bae1fa89ee6958f2d2c2528 (MD5) Previous issue date: 2012-02-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this work was to characterize the agronomic performance of two sunflower genotypes grown under climatic conditions of salinity and water deficit by phenological, physiological and biochemical markers. In this sense, Catissol 01 and Helio 253 sunflower genotypes were cultivated during 3 months in two different areas in the RN state, a salt area (Ipanguaçu-RN IPÇ) and a water deficient area (Parnamirim-RN PAR). After 50 days of the emergency, 30 plants were selected to agronomic analysis like sunflower reproductive period (initial flowering date - DFI, full of bloom date DFP and physiological maturity date DMF), growth indicators and agronomic yield (height AP, diameter chapter DC, number of sheets NF, mass of achenes and grain yield per 1000 RG). Apical leaves from 10 plants were submitted to physiological and biochemical analysis like leaf water status indicators (relative content of water CRA, percentage of moisture %U) and membrane damage (electrolyte leakage VE). In apical, middle and basal leaves were made analysis like ionic stress indicators (Na+, K+, and Cl-) and osmotic adjustment (total soluble sugars-AST, reducing sugars AR, non-reducing sugars ANR, total free amino acids AALT and proline PRO). In PAR it was observed that the plants had their reproductive periods DFI, DFP and DMF retarded with respect to IPÇ to the two genotypes studied. In PAR, Catissol 01 and Helio 253 showed significant reductions in the variables AP (33 and 34%), DC (14 and 21%), NF (10 and 25%), mass of 1000 achenes (31 and 18%), RG (51 and 70%) and CRA (13 and 17%), respectively, compared to IPÇ. The VE was more pronounced in IPÇ than in PAR for both genotypes. It was noted that in PAR, K+ concentrations were higher in all leaves when compared to IPÇ for the two genotypes. Na+ and Cl- levels were higher in IPÇ than on PAR in all leaves for Catissol 01 and Helio 253. Both IPÇ and PAR and for both genotypes, it was not identified ion toxicity by K+/Na+ relation. It was observed that genotype Helio 253 has higher concentrations of AST in the leaves in IPÇ than in PAR. From the pool of AST, it was observed higher concentration of AR in the basal and apical leaves, while ANR was higher in median leaves. The Helio 253 genotype showed higher concentrations of AR in all leaves in PAR. The content of AST of Catissol 01 was higher in IPÇ than PAR, showing higher concentrations of AR in all leaves for the two places of cultivation. The genotype Helio 253 showed higher concentrations of AALT (apical and medians leaves) and PRO in IPÇ than in PAR. The genotype Catissol 01 did not provide significant differences in the content of AALT among IPÇ and PAR, with the exception of median leaves. But this genotype showed higher concentration of PRO in IPÇ (for basal and median leaves) than in PAR. Thus, we concluded that the genotypes showed better performance in IPÇ, that the concentrations of salts in IPÇ were not toxic, but caused signs of damage to the metabolism of both genotypes, that the water deficiency in PAR caused damage and disturbances at the growth and yield in two genotypes, but the variation of osmolytes seems to be associated with metabolic damage instead of the osmotic adjustment, there is evidence that the response of plants to environmental conditions depends on the genotype / O objetivo desse trabalho foi caracterizar, por meio de marcadores fenológicos, fisiológicos e bioquímicos, o desempenho agronômico de dois genótipos de girassol cultivados em condições edafoclimáticas de déficit hídrico e salinidade. Para tanto, os genótipos de girassol Helio 253 e Catissol 01 foram cultivados durante 3 meses, em uma área com presença de sais (Ipanguaçu-RN IPÇ) e outra com deficiência hídrica (Parnamirim-RN PAR) no RN. Após 50 dias da emergência, 30 plantas foram submetidas a análises agronômicas: período reprodutivo do girassol (data de floração inicial - DFI, data de floração plena DFP e data da maturação fisiológica DMF) e indicadores de crescimento e rendimento agronômico (altura AP, diâmetro do capítulo DC, número de folhas NF, massa de 1000 aquênios e rendimento de grãos RG); e 10 plantas foram submetidas a análises de variáveis fisiológicas e bioquímicas das folhas apicais: indicadores de status hídrico (conteúdo relativo de água CRA, percentual de umidade %U) e danos de membrana (vazamento de eletrólitos VE); e em folhas apicais, medianas e basais: indicadores de estresse iônico (Na+, K+ e Cl-) e ajustamento osmótico (açúcares solúveis totais AST e não-redutores ANR, aminoácidos livres totais AALT e prolina PRO). Ao avaliar os períodos reprodutivos do girassol, nos dois genótipos estudados, observou-se que em PAR, as plantas tiveram os seus períodos reprodutivos DFI, DFP e DMF retardados em relação aos de IPÇ. Ao avaliar os dois genótipos cultivados em PAR, observou-se que as plantas apresentaram reduções significativas nas variáveis AP (33 e 34%), DC (21 e 14%), NF (10 e 25%), massa de 1000 aquênios (31 e 18%), RG (70 e 51%) e CRA (13 e 17%), para Catissol 01 e Helio 253, respectivamente, comparadas a IPÇ. O VE foi mais pronunciado em IPÇ, para Catissol 01 (35%) e Helio 253 (54%), do que em PAR. Em PAR, para os dois genótipos, as concentrações de K+ foram maiores, em todas as folhas, quando comparada a IPÇ. Para os dois genótipos, os níveis de Na+ e Cl-, foram maiores em IPÇ do que em PAR, em todas as folhas. Tanto em IPÇ quanto em PAR, nos dois genótipos, não foi verificada toxicidade por íons pela relação K+/Na+. Foi observado, no genótipo Helio 253 em IPÇ, maiores concentrações de AST nas folhas do que em PAR. Do pool total de AST, observou-se maior concentração de AR nas folhas apicais e basais, enquanto que os ANR concentraram-se nas folhas medianas. Em PAR, o Helio 253 apresentou maiores concentrações de AR em todas as folhas. Ao analisar os AST no Catissol 01, observou-se maior concentração em IPÇ quando comparada a PAR, com maiores concentrações de AR nas duas microrregiões em todas as folhas. Em IPÇ, o Helio 253 apresentou maiores concentrações de AALT nas folhas apicais e medianas e de PRO em todas as folhas quando comparado a PAR. O Catissol 01 não apresentou diferenças significativas para o acúmulo de AALT entre IPÇ e PAR, com exceção das folhas medianas, mas apresentou valores superiores na concentração de PRO em IPÇ (folhas medianas e basais), quando comparadas a PAR. Conclui-se assim, que os genótipos apresentaram melhores desempenhos em IPÇ; as concentrações de sais em IPÇ não foram tóxicas, mas causaram indícios de danos ao metabolismo dos genótipos; a deficiência hídrica em PAR causou distúrbios e danos aos processos de crescimento e rendimento nos dois genótipos; a variação dos osmólitos parece estar associada a danos às vias metabólicas e não ao possível ajustamento osmótico; e ainda, há evidências de que a reação das plantas às condições ambientais depende do genótipo

Made available in DSpace on 2016-08-12T19:18:45Z (GMT). No. of bitstreams: 1 YuriLM_DISSERT.pdf: 1834297 bytes, checksum: 18de998f0bae1fa89ee6958f2d2c2528 (MD5) Previous issue date: 2012-02-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this work was to characterize the agronomic performance of two sunflower genotypes grown under climatic conditions of salinity and water deficit by phenological, physiological and biochemical markers. In this sense, Catissol 01 and Helio 253 sunflower genotypes were cultivated during 3 months in two different areas in the RN state, a salt area (Ipanguaçu-RN IPÇ) and a water deficient area (Parnamirim-RN PAR). After 50 days of the emergency, 30 plants were selected to agronomic analysis like sunflower reproductive period (initial flowering date - DFI, full of bloom date DFP and physiological maturity date DMF), growth indicators and agronomic yield (height AP, diameter chapter DC, number of sheets NF, mass of achenes and grain yield per 1000 RG). Apical leaves from 10 plants were submitted to physiological and biochemical analysis like leaf water status indicators (relative content of water CRA, percentage of moisture %U) and membrane damage (electrolyte leakage VE). In apical, middle and basal leaves were made analysis like ionic stress indicators (Na+, K+, and Cl-) and osmotic adjustment (total soluble sugars-AST, reducing sugars AR, non-reducing sugars ANR, total free amino acids AALT and proline PRO). In PAR it was observed that the plants had their reproductive periods DFI, DFP and DMF retarded with respect to IPÇ to the two genotypes studied. In PAR, Catissol 01 and Helio 253 showed significant reductions in the variables AP (33 and 34%), DC (14 and 21%), NF (10 and 25%), mass of 1000 achenes (31 and 18%), RG (51 and 70%) and CRA (13 and 17%), respectively, compared to IPÇ. The VE was more pronounced in IPÇ than in PAR for both genotypes. It was noted that in PAR, K+ concentrations were higher in all leaves when compared to IPÇ for the two genotypes. Na+ and Cl- levels were higher in IPÇ than on PAR in all leaves for Catissol 01 and Helio 253. Both IPÇ and PAR and for both genotypes, it was not identified ion toxicity by K+/Na+ relation. It was observed that genotype Helio 253 has higher concentrations of AST in the leaves in IPÇ than in PAR. From the pool of AST, it was observed higher concentration of AR in the basal and apical leaves, while ANR was higher in median leaves. The Helio 253 genotype showed higher concentrations of AR in all leaves in PAR. The content of AST of Catissol 01 was higher in IPÇ than PAR, showing higher concentrations of AR in all leaves for the two places of cultivation. The genotype Helio 253 showed higher concentrations of AALT (apical and medians leaves) and PRO in IPÇ than in PAR. The genotype Catissol 01 did not provide significant differences in the content of AALT among IPÇ and PAR, with the exception of median leaves. But this genotype showed higher concentration of PRO in IPÇ (for basal and median leaves) than in PAR. Thus, we concluded that the genotypes showed better performance in IPÇ, that the concentrations of salts in IPÇ were not toxic, but caused signs of damage to the metabolism of both genotypes, that the water deficiency in PAR caused damage and disturbances at the growth and yield in two genotypes, but the variation of osmolytes seems to be associated with metabolic damage instead of the osmotic adjustment, there is evidence that the response of plants to environmental conditions depends on the genotype / O objetivo desse trabalho foi caracterizar, por meio de marcadores fenológicos, fisiológicos e bioquímicos, o desempenho agronômico de dois genótipos de girassol cultivados em condições edafoclimáticas de déficit hídrico e salinidade. Para tanto, os genótipos de girassol Helio 253 e Catissol 01 foram cultivados durante 3 meses, em uma área com presença de sais (Ipanguaçu-RN IPÇ) e outra com deficiência hídrica (Parnamirim-RN PAR) no RN. Após 50 dias da emergência, 30 plantas foram submetidas a análises agronômicas: período reprodutivo do girassol (data de floração inicial - DFI, data de floração plena DFP e data da maturação fisiológica DMF) e indicadores de crescimento e rendimento agronômico (altura AP, diâmetro do capítulo DC, número de folhas NF, massa de 1000 aquênios e rendimento de grãos RG); e 10 plantas foram submetidas a análises de variáveis fisiológicas e bioquímicas das folhas apicais: indicadores de status hídrico (conteúdo relativo de água CRA, percentual de umidade %U) e danos de membrana (vazamento de eletrólitos VE); e em folhas apicais, medianas e basais: indicadores de estresse iônico (Na+, K+ e Cl-) e ajustamento osmótico (açúcares solúveis totais AST e não-redutores ANR, aminoácidos livres totais AALT e prolina PRO). Ao avaliar os períodos reprodutivos do girassol, nos dois genótipos estudados, observou-se que em PAR, as plantas tiveram os seus períodos reprodutivos DFI, DFP e DMF retardados em relação aos de IPÇ. Ao avaliar os dois genótipos cultivados em PAR, observou-se que as plantas apresentaram reduções significativas nas variáveis AP (33 e 34%), DC (21 e 14%), NF (10 e 25%), massa de 1000 aquênios (31 e 18%), RG (70 e 51%) e CRA (13 e 17%), para Catissol 01 e Helio 253, respectivamente, comparadas a IPÇ. O VE foi mais pronunciado em IPÇ, para Catissol 01 (35%) e Helio 253 (54%), do que em PAR. Em PAR, para os dois genótipos, as concentrações de K+ foram maiores, em todas as folhas, quando comparada a IPÇ. Para os dois genótipos, os níveis de Na+ e Cl-, foram maiores em IPÇ do que em PAR, em todas as folhas. Tanto em IPÇ quanto em PAR, nos dois genótipos, não foi verificada toxicidade por íons pela relação K+/Na+. Foi observado, no genótipo Helio 253 em IPÇ, maiores concentrações de AST nas folhas do que em PAR. Do pool total de AST, observou-se maior concentração de AR nas folhas apicais e basais, enquanto que os ANR concentraram-se nas folhas medianas. Em PAR, o Helio 253 apresentou maiores concentrações de AR em todas as folhas. Ao analisar os AST no Catissol 01, observou-se maior concentração em IPÇ quando comparada a PAR, com maiores concentrações de AR nas duas microrregiões em todas as folhas. Em IPÇ, o Helio 253 apresentou maiores concentrações de AALT nas folhas apicais e medianas e de PRO em todas as folhas quando comparado a PAR. O Catissol 01 não apresentou diferenças significativas para o acúmulo de AALT entre IPÇ e PAR, com exceção das folhas medianas, mas apresentou valores superiores na concentração de PRO em IPÇ (folhas medianas e basais), quando comparadas a PAR. Conclui-se assim, que os genótipos apresentaram melhores desempenhos em IPÇ; as concentrações de sais em IPÇ não foram tóxicas, mas causaram indícios de danos ao metabolismo dos genótipos; a deficiência hídrica em PAR causou distúrbios e danos aos processos de crescimento e rendimento nos dois genótipos; a variação dos osmólitos parece estar associada a danos às vias metabólicas e não ao possível ajustamento osmótico; e ainda, há evidências de que a reação das plantas às condições ambientais depende do genótipo