Labuschagne, M. T.Osthoff, G.Viljoen, C. D.Gemelal, Adugna Wakjira2018-04-052018-04-052002-11http://hdl.handle.net/11660/8118English: The study was carried out to assess the genetic diversity of 60 linseed accessions mainly collected from Ethiopia in different environments using morphological and amplified fragment length polymorphism (AFLP) markers from 2000 to 2002. AFLP and morphological characterization were conducted under glasshouse conditions at the University of the Free State in South Africa. Similarly, morphological evaluations were undertaken under field conditions at Holetta Research Centre in Ethiopia during 2000 and 2001 cropping seasons. The main objectives of the study were to determine the levels and patterns of genetic diversity along with other genetic parameters using both morphological descriptors and the AFLP markers, and to compare the usefulness and relationships of these two methods in discriminating the accessions of linseed by applying univariate, bivariate and multivariate statistical analyses. The analysis of variance for the glasshouse experiment showed highly significant difference (P < 0.01) among the accessions for Il quantitative traits measured, indicating the presence of high genetic diversity. This result was also confirmed by the principal component analysis (PCA) and cluster analysis (CA). PCA displayed that days to flowering, maturity and seeds/boil accounted for 20% of the total variability. CA grouped the accessions into Il main clusters, consisting one to 24 accessions each. No correspondence was found between clustering and geographic origins of the accessions. Estimation of broad sense heritability and predicted genetic gains (as percent of mean) were also computed to forecast the possible genetic advance in the future. Heritability ranged from 15.60% for seed yield/plant to 85.82% for initial days to flowering, whereas predicted genetic gains varied from 3.16% for days to maturity to 24.26% for plant height. The analysis of variance for the field experiments revealed highly significant differences (P < 0.01) among the accessions for Il characters. PCA and CA also denoted the same thing, showing the presence of a wide range of genetic variations between the accessions studied. CA clustered the accessions into nine classes, each consisting one to 39 accessions. The clustering was independent of collection areas. Phenotypic coefficient of variation ranged from 6.26% (days to maturity) to 54.97% (seed yield/plant), while genotypic coefficient of variation differed from 5.46% to 50.18% for the same characters. Heritability (broad sense) was in the range of 67.38% to 91.38%, whereas the predicted genetic gain varied from 9.38% to 94.37%. In both cases, the highest value was estimated for seeds/ball, while the lowest was for days to maturity. A combined analysis of variance of 10 quantative traits across four environments (two localities and two years) displayed highly significant differences (P < 0.01) among the accessions for all characters. There was also significant difference between the localities, years and their interactions for most characters, indicating the differential responses of the accessions across environments. PCA and CA also confirmed the differences between accessions and the prevalence of diversity among the accessions. PCA displayed that secondary branches/plant, plant height, days to flowering and seed yield/plant played major roles in differentiating the accessions. CA grouped the accessions into nine major clusters based on their mean performance rather than their geographic origins. Broad sense heritability and expected genetic advance were found higher across multi-environments than for the single one, indicating the importance of evaluating germplasm under different and appropriate environments. Both parameters were highest for plant height and days to flowering, indicating the effectiveness of selection for these traits. Diversity analyses for oil content, oil yield and fatty acid profiles generally indicated significant (P < 0.01) variations among the studied accessions. Oil content varied from about 29 to 36%, while oil yield ranged between 1443 and 3276 g/m2. The highest oil yield was obtained from Belay-96, followed by CDCVG (3212 g/m2), an introduction from Canada, which was identified as one the most promising genotypes in this study. Fatty acids that are principally grouped into two main groups (saturated and unsaturated) showed wide ranges of variation. Saturated fatty acids (palmitic and stearic) ranged from about 8 to 12%, whereas the unsaturated (oleic, linoleic and linolenic) ones significantly (P < 0.01) varied from 85 to 91%. The highest variation was recorded for oleic acid (14-29%), followed by linolenic (47-59%) and linoleic (10-16%) fatty acids. The accessions were grouped into six cluster based on their oil content, oil yield and linolenic acid, but into 10classes based on all their fatty acid profiles. Associations of characters were analysed across different environments to determine the extent and consistency of correlations and to identify major yield attributes of linseed. The degrees of correlation varied across years and locations due mainly to climatic factors, such as temperature, moisture regime and disease incidences. Seed yield was significantly (P < 0.01) and positively correlated with yield/plant, boils/plant and 1000-seed weight. These three traits were also strongly and positively related with plant height, branches/plant and days to maturity. Oil yield was significantly and positively associated with polyunsaturated (linoleic and linolenic) fatty acids, while it was negatively correlated with saturated (palmitic and stearic) fatty acids. The results generally showed tremendous variations in correlations of characters in response to the growing environments. The current accessions of linseed were assessed for their genetic variation by using AFLP markers. The estimated genetic distance for the entire pairwise accessions varied from 0.29 to 0.71. The top three pairs of accessions with the highest genetic distance were 22 and 57, 25 and 57 and 20 and 45. High levels of polymorphism were also observed for the analysed accessions, indicating the prevalence of genetic diversity in both exotic and local collections. Collections from central and northwest regions of Ethiopia revealed considerable variations, implying further explorations in these areas. Cluster analysis grouped the accessions into 13 classes, each consisting one to 14 accessions. AFLP was found effective in discriminating and grouping the accessions for more predictable breeding and efficient management of genetic resource in the future. Combining phenotypic and genotypic assessment of genetic diversity could help in acquiring more reliable genetic information for discriminating germplasm and cultivars. To this end, morphological and AFLP data were employed to investigate the levels and patterns of variation existing in linseed accessions and to compare the two methods. Analyses of ANOVA, PCA and CA revealed the existence of wide range of genetic diversity among the accessions. The average genetic distance of all pairwise accessions was 0.6684 for morphology and 0.5734 for AFLP markers. Higher level of variation was noted for morphology than for AFLP. Correlation between the two distances was very weak and their clustering patterns were also different. In fact, clustering patterns were variable based number of traits and environments tested. In spite of this disparity, however, both methods were found independently adequate and useful in germplasm characterization and/ or cultivar identification based on circumstances, like the availability of research facilities, fund and other essential resources.Afrikaans: Hierdie studie is uitgevoer om die genetiese diversiteit te bepaal van 60 lynsaad genotipes wat hoofsaaklik uit Etiopië afkomstig is, met die gebruik van morfologiese en AFLP (amplified fragment length polymorphism) merkers in die tydperk 2000 tot 2002. AFLP en morfologiese karakterisering is gedoen onder glashuis toestande by die Universiteit van die Vrystaat. Morfologiese evaluasies is ook gedoen onder veld toestande by die Holetta Navorsingsstasie in Etiopië in die 2000 en 2001 groeiseisoene. Die hoof doelwitte van die studie was die bepaling van vlakke en patrone van genetiese diversiteit en die gebruik van ander genetiese parameters wat beide morfologiese eienskappe en AFLP merkers insluit, en om hierdie metodes te vergelyk vir bruikbaarheid en die onderskeiodings vermoë binne die lynsaad genotipes deur die gebruik van monovariate en multivariate statistiese analise. Variansie analise van die glashuis eksperiment het hoogs betekenisvolle verskille (P<0.01) tussen inskrywings aangetoon vir die Il kwantitatiewe eienskappe gemeet, wat 'n aanduiding gee van hoë genetiese diversiteit. Die resultate is bevestig met PCA (principle component) analise en CA (cluster analysis). PCA het aangedui dat dae tot blom, rypwording en sade per bol 20% van variabiliteit verklaar het. CA het die inskrywings in Il hoof groepe ingedeel, wat uit een tot 24 inskrywings bestaan het. Geen ooreenkoms is gevind tussen groeperings en geografiese oorsprong van inskrywings nie. Die bepaling van breë sin oorerflikheid en voorspelde genetiese vordering (as persent van die gemiddeld) is gedoen om moontlike genetiese vooruitgang te voorspel. Oorerflikheid het gewissel van 15.6% vir saad opbrengs per plant tot 85.82% vir dae tot blom. Voo~spelde genetiese vordering het gevarieër van 3.16% vir dae tot ryp tot 24.6% vir plant hoogte. Variansie analise vir die veld proefhet betekenisvolle (p<0.01) verskille aangetoon tussen inskrywings vir die Il eienskappe. PCA en CA het dieselfde aangetoon, wat 'n wye reeks van genetiese variasie aandui vir die inskrywings. CA het die inskrywings in nege groepe gedeel wat een tot 39 inskrywings gehad het. Die groeperings was onafhanklik van versamelings plekke. Fenotipiese koeffisiënt van variasie het gewissel van 6.26% (dae tot ryp) tot 54.97% (saad opbrengs per plant). Genotipiese CV het gewissel van 5.46% tot 50.18% vir dieselfde eienskappe. Oorerflikheid (breë sin) het gewissel van 67.38% tot 91.38%, en die verwagte genetiese vordering het gewissel van 9.38% tot 94.37%. In beide gevalle was die hoogste waarde vir saad per bol, en die laagste vir dae tot rypheid. 'n Gekombineerde variansie analise vir 10 kwantitatiewe eienskappe oor vier omgewings (twee lokaliteite en twee jare) het betekenisvolle verskille (P<0.01) tussen inskrywings vir alle karakters getoon. Daar was ook betekenisvolle verskille tussen lokaliteite, jare en hulle interaksie vir meeste eienskappe, wat differensiële response van inskrywings oor omgewings aantoon. PCA en CA het ook die verskille tussen inskrywings beklemtoon, en die teenwoordigheid van diversiteit tussen inskrywings. PCA het gewys dat sekondêre vertakkings per plant, plant hoogte, dae tot blom en saad opbrengs per plant 'n groot rol speel in die differensiasie van die inskrywings. CA het inskrywings in nege groepe verdeel gebaseer op gemiddelde prestasie eerder as geografiese oorsprong. . Breë sin oorerflikheid en verwagte genetiese vordering was hoër oor omgewings as in enkele omgewings, wat die belangrikheid onderstreep om kiemplasma te evalueer onder verskillende en geskikte omgewings. Beide hierdie parameters was die hoogste vir plant hoogte en dae tot blom wat aandui dat hierdie eienskappe effektief geselekteer kan word. Diversiteits analise vir olie inhoud, olie opbrengs en vetsuur profiele het oor die algemeen betekenisvolle (P<0.01) variasies tussen inskrywings getoon. Olie inhoud het gewissel tussen 29% tot 36%, en olie opbrengs tussen 1443 tot 3276 g/m2. Die hoogste olie opbrengs is gekry van Belay-96, gevolg deur CDC-VG (3212g/m2), 'n introduksie van Kanada, wat identifiseer is as een van die mees belowende genotipes in hierdie studie. Vetsure wat gegroepeer is in twee hoof groepe (versadig en, onversadig) het groot variasie getoon. Versadigde vetsure (palmities en stearien suur) het gewissel van 8% tot 12%, en onversadigde (oleïen, linoïen en linoleen) vetsure het betekenisvol gevarieër van 85% tot 91%. Die hoogste variasie is aangetoon vir oleïensuur (14-29%), gevolg deur linoleensuur (47-59%) en Iinoïen (10-16%) vetsure. Die inskrywings is gedeel in ses groepe gebaseer op olie inhoud, olie opbrengs en linoleensuur, maar in 10klasse gebaseer op vetsuur profiele. Assosiasie van karakters is geanaliseer oor verskillende omgewings om die omvang en herhaalbaarhied van korrelasies vas te stel, en om die grootste bydraers van opbrengs by lynsaad te bepaal. Die graad van korrelasie het gewisseloor jare en lokaliteite a.g.v. klimatiese faktore soos temperatuur, vog en siekte insidensie. Saad opbrengs was betekenisvol (P<0.01) en positief gekorreleer met opbrengs per plant, kapsules per plant en 1000 saad gewig. Hierdie drie eienskappe was ook sterk positief gekorreleer met plant hoogte, vertakkings per plant en dae tot rypheid. Olie opbrengs was betekenisvol en positief gekorreleer met polionversadigde (linoïen en linoleen) vetsure, terwyl dit negatief gekorreleer is met versadigde (palmitiese en stearien) vetsure. Die resultate het oor die algemeen geweldige variasie gewys in korrelasies van karakters in reaksie op omgewings toestande. Met die gebruik van AFLP is die lynsaad inskrywings geëvaleer vir genetiese variasie. Die genetiese afstand vir paarsgewyse vergelykings het gewissel van 0.29 tot 0.71. Die top drie paar inskrywings met die grootste genetiese afstande was 22 en 57, 25 en 57 en 20 en 45. 'n Hoë vlak van polimorfisme is waargeneem vir die geanaliseerde inskrywings wat heelwat genetiese diversiteit aantoon in beide eksotiese en plaaslike versamelings. Versamelings van sentraal en die noordwestelike areas van Etiopië het aansienlike variasie getoon, dus moet hierdie gebiede verder ondersoek word. Groep analise het die inskrywings in 13 klasse gedeel, met elk een tot 14 inskrywings. AFLP's was effektief om inskrywings te onderskei en te groepeer vir meer effektiewe teling en beter bestuur van genetiese bronne in die toekoms. Gekombineerde fenotipiese en genotipiese assessering van genetiese diversiteit kan help om meer betroubare genetiese inligting te kry om kiemplasma en cultivars te onderskei. Om dit te doen is morfologiese en AFLP data gebruik om die vlakke en patrone van variasie in lynsaad genotipes te bepaal en om die twee metodes te vergelyk. ANOVA, PCA en CA analises het wye genetiese diversiteit aangetoon in inskrywings. Die gemiddelde genetiese afstand vir alle paarsgewyse vergelykings was 0.6684 vir morfologiese en 0.5734 vir AFLP merkers. 'n Hoër vlak van variasie was teenwoordig vir morfologie as vir AFLP. Korrelasie tussen die twee afstande was swak, en groeperings patrone was verskillend. Ten spyte van verskille, is beide metodes effektief gevind om afsonderlik gebruik te word vir kiemplasma karakterisering en/of cultivar identifikasie afhangend van omstandighede soos die beskikbaarheid van navorsings geriewe, fondse en ander belangrike hulpbronne.enFlax -- BreedingFlax -- GeneticsThesis (Ph.D. (Plant Sciences (Plant Breeding))--University of the Free State, 2002ThesisUniversity of the Free State