Labuschagne, M. T.Koekemoer, F. P.Mamuya, Ibrahim Ndekurusa2018-05-172018-05-172000-05http://hdl.handle.net/11660/8297English: The primary aim of this study was to examine the effect of environment, genotype and their interaction on bread-making quality characteristics of irrigated spring wheat cultivars. The wheat samples were obtained from trials conducted in irrigation areas by the Small Grain Institute (Breeding Department), during 1997 and 1998. The trials were conducted at six localities in 1997 and seven in 1998. Among the localities five were in cooler and two in warmer irrigation areas. For the cultivars nine were common in both years but two were added in 1997, and one in 1998 making a total of 11 and 10 respectively. The source of cultivars was Small Grain Institute (5) and Sensako (7). Trials were conducted at experimental stations or farms of collaborators where the soil and climate are representative of a specific area. A randomised block design with four replications was used. Interrow spacing was maintained at 0.17 m and planting rate varied according to 1000 kernel mass of a specific cultivar. This was to ensure that a uniform stand of plants per m-2 is achieved. Fertilizers were applied according to recommendations on the basis of individual soil analyses. Other management practices were performed as required and a net plot of six rows (5.1 m-2) was harvested. The samples were analysed for a total of 21 quality characteristics, important for bread-making. The statistical analysis of the results showed that both genotype, environment and their interaction had significant influence on quality characteristics. This implied presence of variations among genotypes, environmental conditions as well as interaction effects in their response to quality parameters. However, above all, environment was the most dominant factor, which contributed to the variation for' most of the characteristics. Protein content (particularly flour) closer to 12% (optimum) and with good quality was very important. This character together with higher grain filling to ensure optimum starch-protein interaction were necessary for cultivars, sites and interaction effects to show good quality characteristics. Generally climatic conditions particularly temperature showed interference with quality parameters especially in warmer areas. This is due to the fact that high temperature has an influence on protein composition and definitely the ratios of glutenin-ta-gliadin part of the protein. However, for cooler areas, the protein quality was probably not affected, but the higher grain filling realised at some of the sites caused protein content to be low. This is again due to the fact that in high potential environments, nitrogen (N) is first utilised for maximum plant growth and yield. Thereafter the excess N is then translocated to the grain for storage as protein. Considering the quality parameters themselves, some showed negative correlations with others. This indicates that improvement of one characteristic will have a negative influence on the other, and this is the cause of breeders delay in releasing new cultivars. By using the canonical variate analysis (cómponent of AMMI), it was possible to see which characteristics group together in discriminating among genotypes, locations and interaction effects. Therefore with this analysis it was possible to determine which characters need appropriate genotype, environment or interaction effects to get optimum values. From the study results we can recommend that, T4, which ranked lower for most of the quality parameters may be risky for very large commercial production. However, this genotype may be used as a donor parent for improvement of alveograph P/L ratio for which it showed good results. Other genotypes, which also showed less potential, include, SST65, SSTSS, SST876 and Palmiet. These genotypes should be grown under conditions where they are expected to perform well. An example is Palmiet at Loskop, Koedoeskop and BullHill where it showed positive environment interactions for loaf volume at 12% protein. Also with environment protein yield closer to optimum (not very low), Palmiet may perform intermediately for most of the parameters. SST55 and SST65 showed higher loaf volumes at 12% protein and may be used to improve this parameter. Nevertheless they were lower in other parameters particularly mixograph development time, mixograph point score and SDS-sedimentation. Kariega ranked lower for alveograph P/L ratio in both years and may need improvement for this parameter. However, this genotype together with SST38, SST57, SST822, SST825, Inia and Marico showed intermediate to higher rank for most of the characteristics. Therefore they may be reliable at most of the sites unless environment becomes less optimal or negative environment interactions occur. For the locations, Loskop was the site that showed the most contrast with other sites. This is due to the fact that this site had values for mixograph development time, and to a lesser extent mixograph point score above recommended values for both years. Also the high protein realised at this site implies management practices should be aimed at reducing fertility and thus nitrogen yield. Therefore at Loskop, Koedoeskop (warmer areas) and Barkly West, cultivar selection and timing of seeding are necessary to ensure that grain filling is not influenced or does not coincide with higher temperatures. The higher hectoliter and kernel masses at most of the sites except Loskop implies higher grain yields and this was the main cause of realised low protein content. Therefore for other sites in addition to cultivar selection, management practices to increase fertility and thus protein content are necessary particularly at Prieska. Also since leaching may lose fertility, there is a need to control the irrigation water. Genotype x environment interactions were observed for protein content and related parameters. Grain filling was also responsible for this interaction particularly for the parameters influenced by starch-protein interaction. However, Prieska, and to a lesser extent Douglas showed less environment interactions compared to other sites. Therefore at Loskop, Koedoeskop, Hopetown, BullHilI and Barkly West identification of genotypes with positive environment interactions will be necessary. The canonical variate analyses for genotypes showed that 10 parameters were mainly responsible for the variations among genotypes. Mixograph development time, mixograph point score, alveograph P/L ratio, alveograph strength, loaf volume at 12% protein, SDS-sedimentation, breakflour yield, kernel mass (TKM and SKCS-W) and SKCS-diameter were responsible for genotype variation. Therefore for all these parameters, identification of cultivars, which will give desirable values, is important. Breeders may give them priority when making selection in their programmes. The canonical variate analysis for environments showed more parameters, about 13 being influenced by the environment variations. However, most of them were associated with protein content and grain filling. Most of the characteristics, which discriminated the interaction effects, were those under genotype and environment. Therefore identification of cultivars, which will give good results, and management to ensure higher protein with good quality and higher grain filling, are necessary. Taking into account the grading of wheat Prieska and Douglas showed to be stable and may give a BSS grade for most of the cultivars. BuIIHilI, Hopetown, Barkly West and Koedoeskop had intermediate stability and gave BS1 and BS2 grade for most of the cultivars particularly in 1998 due to low protein content. Loskop was alone showing to be highly unstable as it gave BS2 in 1997 for all cultivars, and in 1998 they were BPS and BP1. However, for this site despite the grade being higher, quality characteristics may show low values. Therefore cultivar selection and management are important to ensure that the grades are maintained and quality characteristics to be closer to optimum. Also mixing the products, particularly from Loskop and to a lesser extent BuIIHilI, Barkly West, Hopetown and Koedoeskop when the environments are not optimal with those of Prieska and Douglas will improve the quality. The probable cultivars to be mixed are SST825, Inia, SST822, SST57, SST38 and to a lesser extent Marico and Kariega. Therefore there is a need for processing industries and particularly researchers and farmers to work closer together. This will help to identify which cultivars and management practices need to be implemented at certain locations in order to have good quality crops. Also, since farmers are risk takers, despite following all the recommendations, environmental deviation may cause their products to have reduced/poor quality. In such a case, the government and processing industries should have a programme of supporting such farmers.Afrikaans: Die primêre doel van hierdie studie was om die effek van die omgewing, genotipe en die interaksie daarvan te bepaal op broodbak kwaliteit eienskappe van lente besproeiings koring cultivars. Die koring cultivars is verkry vanaf proewe wat in die besproeiings areas gedoen is deur die Kleingraan Instituut (telings afdeling) gedurende 1997 en 1998. Die proewe is uitgevoer in ses lokaliteite in 1997 en sewe in 1998. Vyf van die lokaliteite was in die koeler en twee in die warmer besproeiings areas. Nege cultivars was gemeenskaplik vir albei jare, maar daar was twee ekstra iii 1997, en een in 1998, wat 'n totaal van 11 cultivars vir 1997 en 10 vir 1998 gee. The bron van cultivars was die Kleingraan Instituut (5) en Sensako (7). Proewe is gedoen op navorsings plase of plase van samewerkers waar die grond en klimaat verteenwoordigend is van die spesifieke area. 'n Gerandomiseerde blok ontwerp met vier herhalings is gebruik. Interry spasiëring was 0.17 m en plant digtheid is bereken volgens die 1000 korrel massa van die cultivars sodat 'n univorme plant stand per area verkry is. Bemesting is gedoen volgens grond analises. Ander bewerkings praktyke is uitgevoer soos nodig, en uiteindelik is ses rye (5 m') geoes. Die monsters is geanaliseer vir 'n totaal van 21 kwaliteits eienskappe wat belangrik is vir broodbak kwaliteit. Die statistiese analise van die resultate het aangetoon dat beide genotipe, omgewing en hulle interaksie 'n betekenisvolle invloed het op kwaliteits eienskappe. Dit het die aanwesigheid van variasie aangetoon tussen genotypes, omgewing en die interaksie effekte in hulle reaksie op kwaliteits eienskappe. Omgewing was die .dorninante faktor wat bygedra het tot variasie vir meeste van die eienskappe. Proteïen inhoud (veral meel proteïen) na aan 12% (optimum) en met goeie kwaliteit, was baie belangrik. Hierdie eienskap, tesame met hoër graanvul wat optimum stysel-proteïen interaksie gee, was nodig vir cultivars, omgewings en interaksie effekte voordat goeie kwaliteits eienskappe getoon is. Oor die algemeen het omgewing, en veral temperatuur 'n groot invloed gehad op kwaliteits eienskappe, veral in die warmer areas. Dit is omdat hoë temperatuur 'n invloed het op proteïen samestelling en veral die glutenien tot gliadien verhouding. Maar vir die koeler areas is ·die proteïen kwaliteit waarskynlik nie beïnvloed nie, maar die hoër graanvul wat gerealiseer is by party areas het laer proteïen inhoud veroorsaak. Dis weereens a.g.v. die feit dat in hoë potensiaalomgewings stikstof (N) eerste gebruik word om maksimum plant groei en opbrengs te verseker. Daarna word die orige N gebruik om proteïen te stoor. Vir die kwaliteits eienskappe was daar 'n aantal negatiewe korrelasies. Dus sal seleksie vir een eienskap 'n ander negatief beïnvloed, wat veroorsaak dat teling vertraag word. Deur die gebruik van 'n kanoniese variaat analise ('n komponent van AMMI), was dit moontlik om te sien watter eienskappe saam groepeer tussen genotypes, omgewings en interaksie effekte. Met hierdie analise was dit moontlik om te sien watter eienskappe sekere genotipes, omgewings of interaksie benodig om optimum waardes te kry. N.a.v. hierdie studie word aanbeveel dat T4, wat laag op die rangorde was vir meeste kwaliteits eienskappe riskant is vir kommersiële produksie. Die cultivar kan wel gebruik word vir die verbetering van alveogram PIL verhouding, waar dit goeie waardes gehad het. Ander genotypes wat ook swak vertoon het was, 88T65, 88T55, 88T876 en Palmiet. Hierdie genotipes moet net in omgewings geplant word waar dit goed sal presteer. Bv. Palmiet by Loskop, Koedoeskop en BuIIHilI waar dit positiewe omgewings interaksie getoon het vir brood volume by 12% proteïen. Ook waar proteïen inhoud optimaal is (nie te laag nie) sal Palmiet gemiddeld presteer vir meeste eienskappe. 88T55 en 88T65 het hoër brood volumes getoon by 12% proteïen en kan gebruik word om hierdie eienskap te verbeter. Maar hulle het weer swakker presteer vir ander eienskappe veral miksogram ontwikkelings tyd en punt waarde en 8D8 sedimentasie. Kariega het laer waardes gehad vir PIL verhouding in beide jare en hierdie eienskap sal waarskynlik verbeter moet word. Tog het hierdie genotipe saam met 88T38, 88T57, 88T822, 88T825, Inia en Marico gemiddeld tot effens beter vertoon vir meeste eienskappe. Hulle mag daarom betroubaar wees in meeste omgewings behalwe as die ongewing verswak of negatiewe interaksies met die omgewing voorkom. Vir die omgewings het Loskop die meeste kontras met die ander getoon. Dit was a.g.v. die feit dat hierdie omgewing waardes bo die aanbevole waardes gehad het vir miksogram ontwikkelingstyd en tot 'n mindere mate die punt waarde vir beide jare. Die hoë proteïen inhoud wat gerealiseer is vir hierdie omgewing dui aan dat bestuurspraktyke gerig moet wees daarop om die grond vrugbaarheid te verlaag sodat N opbrengs verlaag kan word. Daarom by Loskop, Koedoeskop (warmer areas) en Barkly Wes is dit nodig om planttyd te reel sodat graanvul periode nie beïnvloed word of ooreenstem met die warmste tye nie. Die hoër hektoliter massa en korrel massas by meeste lokateite behalwe Loskop dui hoër graan opbrengs aan, wat die hoof rede was vir verlaagde proteïen inhoud. Daarom, vir hierdie lokaliteite, behalwe vir cultivar seleksie, moet bestuurs praktyke aangepas word om grondvrugbaarheid te verhoog, en gevolglik proteïen inhoud. Stikstof mag verlore gaan a.g.v. loging, en besproeiing moet daarom effektief toegedien word. Genotipe x omgewing interaksies is gesien vir proteïen inhoud en verwante eienskappe. Graanvul was ook verantwoordelik vir hierdie interaksie veral vir eienskappe wat beïnvloed is deur stysel-proteïen interaksie. Maar, Prieska, en tot 'n mindere mate Douglas het minder interaksies aangetoon in vergelyking met ander lokaliteite. Daarom, by Loskop, Koedoeskop, BuIIhilI en Barkly Wes is identifikasie van cultivars met positiewe omgewings interaksies nodig. Die kanoniese variaat analise vir genotypes het aangetoon dat 10 eienskappe verantwoordelik is vir variasie tussen genotipes. Miksogram ontwikkelingstyd en punt waarde, alveogram PIL verhouding, alveogram sterkte, brood volume by 12% protein, 8D8-sedimentasie, breekmeel opbrengs, korrel massa (TKM en 8KC8-W) en 8KC8 deursnee was verantwoordelik vir die variasie. Daarom, vir al hierdie eienskappe is identifikasie van genotipes nodig wat gewenste waardes sal gee. Telers moet voorkeur hieraan gee as seleksies in programme gemaak word. Die kanoniese variaat analise vir omgewings toon dat ongeveer 13 eienskappe verantwoordelik is vir omgewings variasies. Meeste van hulle was geassosieer met proteïen inhoud en graanvul. Meeste van die eienskappe wat gediskrimineer het tussen interaksie effekte was dieselfde as die vir genotipe en omgewing. Daarom sal identifikasie van cultivars wat goeie resultate sal gee, sowel as bestuurspraktyke om hoër proteïen met goeie kwaliteit en hoër graanvul te gee, noodsaaklik'. Met die gradering was cultivars by Prieska en Douglas stabiel en sal dit B88 graad gee vir meeste cultivars. BuIIhilI, Hopetown, Barkly Wes en Koedoeskop gee gemiddelde stabiliteit met BS1 en BS2 gradering vir meeste cultivars, veral in 1998 a.g.v. lae proteïen. Loskop was hoogs onstabiel met BS2 gradering in 1997 vir alle cultivars, en in 1998 BPS en BP1. Ten spyte van hoër gradering kan sekere kwaliteits eienskappe swak wees. Daarom is cultivar seleksie en bestuur blangrik om te verseker dat grade behou word, en dat kwaliteits eienskappe nabyoptimum is. Produkte kan vermeng word vir Loskop, en tot 'n mindere mate ook BuIIhilI, Barkly Wes, Hopetown en Koedoesop met Prieska en Douglas om kwaliteit te verbeter as die omgewings nie optimaal is nie. Die waarskynlike cultivars wat gemeng moet word is SST825, lnia, SST822, SST57, SST38 en tot 'n mindere mate Marico en Kariega. Daar is gevolglik 'n behoefte aan samewerking tussen die prosesserinqs bedryf, die navorsers en die boere. Dit sal help om goeie cultivars en bestuurspraktye te identifiseer vir sekere lokaliteite om goeie kwaliteit koring te produseer. Boere is risiko nemers, en al volg hulle aanbevelings, kan ongewings afwykings veroorsaak dat hulle produkte swak of verlaagde kwaliteit het. In hierdie geval moet die staat en die industrie 'n ondersteunings program hé vir sulke boere.enWheatWheat -- ProcessingGenotype-environment interactionDissertation (M.Sc. (Agric. (Plant Breeding))--University of the Free State, 2000DissertationUniversity of the Free State