Van Deventer, C. S.Labuschagne, M. T.Aucamp, J. C.2018-04-042018-04-042003http://hdl.handle.net/11660/8090English: The objectives of this research were to assess South African winter and facultative bread wheat cultivars for milling quality, to study the effect of genotype x environment interaction on the stability of the wheat quality and to characterise the cultivars for milling performance. Thirteen hard red varieties were planted at six localities throughout the Free Sate at two planting dates, during 1997 to 1999. Betta-DN, Gariep, Molen, SST 367, SST 966 and Tugela-DN were planted at the first planting date. Betta-DN, Caledon, Elands, Gariep, Limpopo, PAN 3235, PAN 3349, SST 124, SST 972 and Tugela-DN were planted at the second date. Material was evaluated for test weight, thousand kernel weight, kernel diameter, kernel hardness, moisture content, vitreous kernels, break flour yield, flour yield, flour colour and flour protein content. Combined ANOVA's for the characteristics was performed over environments. Cultivar differences were determined by means of the least significant difference at individual localities. The analysis indicated highly significant differences among genotypes, environments and GXE interactions, for most of the measured traits. Genotypes contributed significantly to the variance in BFLY, DIAM, TKW and Hl. Environment had a large effect on TW, MOIST, VK, FLY, FCL and FPC. Significant GXE interactions were present for most of the quality traits. Canonical variate analysis was used to differentiate between cultivar groups and indicated that TKW, DIAM, HI, BFLY and TW could effectively differentiate between cultivars. The groups observed with regard to the mentioned characteristics were Gariep with Betta-DN and Molen with SST 966. Tugela-DN and SST 367 were not similar to any other cultivars. At the second planting date, Tugela-DN grouped with SST 124. Betta-DN, Caledon, Elands, Gariep, Limpopo and PAN 3235 formed a group. SST 972 and PAN 3349 were not similar to each other or to the other cultivars. The correlation matrix was performed, to calculate phenotypic relationships between quality traits. TKW had positive correlations with DIAM and these two characteristics indicated positive correlations with MOIST. HI correlated positively to TW and also correlated positively to VK. HI and VK correlated negatively to BFLY. High negative correlations were found between HI and FLY. FLY had positive correlations with BFLY, but correlated negatively with FLC. Stepwise multiple regressions indicated that only small percentages of the variation in TW, HI, BFLY, FLY and FLC could be explained by the other kernel and milling characteristics. HI explained the variation in the TW the most effectively. VK and MOIST could be regarded as the most important variance predictors for HI. Predictors for BFLY were kernel size and HI. These characteristics could define 41.6 to 63.3% of the variation in BFLY. Kernel hardness measurements, HI, BFLY and VK were the most definable for flour yield, together they interpreted up to 50.0% of the variation in FLY. TW explained less than 4% of the variation in FLY; therefore TW is not always reliable in predicting flour extraction. The kernel size explained less than 9.6 to 20.7% of the variation in FLY, illustrating the difficulty of predicting flour yield by indirect calculations. The most important variable in predicting FCL was FLY. AMMI analysis of variance was performed to investigate the influence of the GXE interaction on milling quality. Every locality by year combination was treated as a separate environment. Analysis confirmed differences in genotype performance, that there were varying growth conditions among the localities and the presence of GXE interactions. Interaction effects on TW, percentage VK, FLY, FCL and FPC, were large. IPCA 1 stability scores were compared to the AMMI stability values. Molen was the most stable cultivar at the first planting date. At the second planting date, PAN 3235 and Limpopo were the stable cultivars. Betta-DN, SST 124 and Caledon were also quite stable. Tugela-DN, PAN 3349, as well as the hybrid cultivars SST 966 and SST 972, were unstable with regard to milling quality. Milling performance, as calculated by flour extraction, ash contents and flour colour in various formulas, revealed Gariep and Betta-DN as the high performing cultivars (first planting date), while Molen and Tugela-DN reflected poorer performances. The most effective performing cultivars at the second planting dates were SST 124, PAN 3235, Betta-DN and Limpopo. PAN 3349, SST 972 and Tugela-DN indicated poorer milling performances.Afrikaans: Die doel van hierdie studie was om Suid Afrikaanse winter en fakultatiewe broodkoring kultivars te bestudeer ten opsigte van hul maalkwaliteit. Die effek van die kultivar x omgewing interaksie op die graan- en maalkwaliteit is ook ondersoek, gevolglik is die kultivars dan ook gekarakteriseer volgens maalprestasie. Dertien kultivars is gedurende 1997 tot 1999 op ses lokaliteite, by twee plantdatums in die Vrystaat aangeplant. Betta-DN, Gariep, Molen, SST 367, SST 966 en Tugela-DN is ingesluit by die eerste aanplanting. Betta-DN, Caledon, Elands, Gariep, Limpopo, PAN 3235, PAN 3349, SST 124, SST 972 en Tugela-DN is ingesluit in die tweede aanplanting. Die material is geëvalueer vir hektolitermassa, duisendkorrelmassa, korreldeursnit, hardheid, voginhoud, horingagtige korrels, breekmeelopbrengs, meelekstraksie, meelkleur en proteïeninhoud van die meel. Gesamentlike variansie analises vir al die eienskappe, oor die verslillende lokaliteite, is uitgevoer. Kultivar verskille op elke lokaliteit is bepaal met behulp van die kleinste betekenisvolle verskil tegniek. Die analise het verskille tussen genotipes, omgewings en genotipe x omgewing (GXE) interaksies vir die meeste eienskappe aangedui. Genotipes het grootliks bygedra tot die variasie in breekmeelopbrengs, korreldeursnit, duisendkorrelmassa en hardheid. Hektolitermassa, voginhoud, horingagtige korrels, ekstraksie, meelkleur en proteïeninhoud is hoofsaaklik deur die omgewing beïnvloed. Daar was ook betekenisvolle interaksie tussen die genotipes en die omgewing vir die meeste kwaliteitseienskappe wat bepaal is. CVA analises is gebruik om verskille tussen kultivargroepe uit te wys. Hierdie analises het duisendkorrelmassa, korreldeursnit, breekmeelopbrengs, hardheid en hektolitermassa uitgesonder as die eienskappe wat effektief tussen groepe kultivars kan onderskei. Groepe wat hiervolgens aangedui is, was Gariep met Betta-DN en Molen met SST 966 by die eerste aanplanting. Tugela-DN en SST 367 het nie ooreenkomste met mekaar of enige van die ander kultivars gehad nie. By die tweede aanplanting het Tugela-DN en SST 124 saam gegroepeer, terwyl Betta-DN, Caledon, Elands, Gariep, Limpopo en PAN 3235 'n groep gevorm het. SST 972 en PAN 3349 het van mekaar en ook van al die ander kultivars verskil. Korrelasiematrikse om die fenotipiese verwantskappe tussen die kwaliteitseienskappe te bepaal is uitgevoer. Duisendkorrelmassa het positief met korreldeursnit gekorreleer. Hierdie twee eienskappe het ook positiewe verwantskappe met voginhoud gehad. Hektolitermassa en hardheid was positief gekorreleerd, so ook het hardheid en die persentasie horingagtige korrels positiewe korrelasies getoon. Hardheid en die persentasie horingagtige korrels was negatief gekorreleerd met breekmeelopbrengs. Daar was 'n hoë negatiewe korrelasie tussen ekstraksie en hardheid. Ekstraksie was positief gekorreleerd met breekmeelopbrengs en negatief met meelkleur. Stapsgewyse meervoudige regressies is ingespan om die variasie in hektolitermassa, hardheid, breekmeelopbrengs, meelekstraksie en meelkleur te bepaal. Dit het aangedui dat die ander graan- en maaleienskappe slegs 'n klein persentasie van die variasie in die vaste eienskap kon verklaar. Hektolitermassa variasies is die beste deur hardheid beskryf. Horingagtige korrels en voginhoud kan beskou word as die belangrikste voorspellers vir variasie in die graan hardheid. Pitgrootte en hardheid het 41.6 tot 63.3% van die variasie in breekmeelopbrengs verklaar. Hardheidsbepalers, naamlik die horingagtige korrels, breekmeelopbrengs en hardheidsindeks, was die mees verklarende eienskappe vir die variasie in ekstraksie en het soveel as 50% van die variasie in ekstraksie verklaar. Hektolitermassa het egter minder as 4% van die variasie in meelopbrengs verklaar en wys dat hektolitermassa nie altyd 'n betroubare voorspeller van ekstraksie is nie. Pitgrootte het slegs 9.6 tot 20.7% van die variasie verklaar en dui verder op die ingewikkeldheid van ekstraksie bepalings d.m.v. indirekte metodes. Die belangrikste veranderlike in die bepaling van meelkleur was ekstraksie, maar minder as 32% van die variasie is só verklaar. Die AMMI analise is uitgevoer om GXE interaksies se invloed op maalkwaliteit te ondersoek. Elke lokaliteit en jaar kombinasie is as 'n individuele omgewing beskou. Die analise het verskille tussen genotipes en omgewings bevestig en die teenwoordigheid van interaksies aangedui. GXE interaksies het 'n betekenisvolle invloed op hektolitermassa, horingagtige korrels, ekstraksie, meelkleur en meelproteïen gehad. Die IPCA 1 stabiliteitswaardes is met die AMMI stabiliteitswaardes vergelyk. Molen was die stabielste kultivar t.o.v. die meeste eienskappe, by die eerste aanplanting. By die tweede aanplanting was PAN 3235 en Limpopo die stabiele kultivars, Betta-DN, SST 124 en Caledon was ook betreklik stabiel. Tugela-DN en PAN 3349 het onstabiele kwaliteitseienskappe getoon, terwyl die basters, SST 966 en SST 972 ook onstabiel was. Maalprestasies is bereken met formules wat meelopbrengs, as-inhoud en meelkleur bevat. Gariep en Betta-DN was die mees effektiewe presteerders (eerste aanplanting), terwyl Molen en Tugela-DN die laagste rangordes ingeneem het. Kultivars met die beste maalprestasies, by die tweede aanplanting, was SST 124, PAN 3235, Betta-DN en Limpopo. PAN 3349, SST 972 en Tugela-DN het laer prestasiewaardes getoon.enBread wheatCorrelationsEnviromentGenotypeGXE interactionKernel and flour characteristicsMilling performanceMilling qualityWheat -- MillingWheat -- QualityGenotype-environment interactionDissertation (M.Sc.Agric. (Plant Sciences (Plant Breeding))--University of the Free State, 2003DissertationUniversity of the Free State