The inheritance and influence of low molecular weight glutenin subunits on the breadmaking quality of South African wheat cultivars

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Date
2001-05
Authors
Du Preez, Elizabeth Adriana
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University of the Free State
Abstract
English: 1 The aim of this study was to study: a) The inheritance of LMW-GS in 50 F2 lines of eight different Tugela crosses. b) The effect of the different LMW-GS on breadmaking quality using F2:3 derived lines in order to determine the usability of the LMW-GS as markers for baking quality. c) The usability of F2:3 derived lines in early generation selection for the improvement of breadmaking quality. 2 a) The cultivar and the F2 progeny of the eight crosses were screened in a gliadin-free background using a simplified one-dimensional procedure of Singh et al (1991). The HMW and LMW glutenins were run on a single gel. b) The F2:3 derived lines of eight different Tugela crosses were evaluated for breadmaking quality using the procedures of the American Association of Cereal Chemistry (AACC). 3 The results were as follows: a) Only four percent of the F2 progeny of the eight Tugela crosses, contained no bands on the A genome. b) Banding patterns were expressed simultaneously in the F2 progeny and in the pure breeding cultivars. This contrasted with the findings of Gupta and Shepherd (1990b), who found that only one banding pattern for each chromosome was expressed in pure breeding cultivars. c) Due to interaction between the parent types, new banding patterns were formed by recombination. d) Some cultivars had no matching combinations in the B- and 0 genome. Polymorphisms are common in wheat and new banding combinations are quite possible. e) It would seem that none of the "normal" inheritance patterns (eo-dominant) were followed, but rather that there is some kind of suppression of banding patterns in the F2 lines on some of the genomes. f) The quality results showed many differences between the crosses of Tugela and the parent, Tugela. It was already possible in the early generation (F 2:3) to observe an improvement in the reduction of the stability of the dough of Tugela. g) The complexity of the LMW-GS patterns made it difficult to correlate between certain LMW-GS and certain quality parameters. 4 The conclusions from this study: a) The inheritance of LMW-GS in South African wheat material is much more complex than expected. b) The South African material did not always follow the inheritance and banding patterns as described in the nomenclature of Gupta and Shepherd (1990b). c) The differences in LMW-GS composition should explain most of the differences in breadmaking quality in the Tugela crosses, because there was little or no differences in the HMW-GS composition. d) Early generation quality tests (F2:3) could give an indication of the advances made in the improvement of breadmaking quality, although it is very difficult and much more research is needed. e) The unexpected segregation patterns in the F2 progeny, together with multiple combination expression will make marker-assisted-selection on ground of LMW-GS difficult at this early stage. f) The contribution by the parents to the LMW-GS were so diverse, that no single banding pattern could be identified, which definitely influenced the baking quality. g) Until the nomenclature system of Gupta and Shepherd (1990b) is updated with these possible unique South African LMW-GS patterns, the correlation of LMW-GS data with quality results will be very difficult.
Afrikaans: 1 Die doel van die studie was om: a) Die oorerflikheid van die LMW gluteniene in 50 F2 nageslagte van agt verskillende Tugela kruisings te bepaal. b) Die effek van verskillende LMW gluteniene op broodbakkwaliteit te bepaal, deur F2:3 ontwikkelde lyne te gebruik. So word dan bepaal wat die bruikbaarheid van die LMW gluteniene is as merkers vir broodkwaliteit. c) Die bruikbaarheid van F2:3 ontwikkelde lyne in vroeë generasie seleksies vir verbeterde broodbakkwaliteit te bepaal. 2 a) Verskillende cultivars is geëvalueer in 'n agtergrond wat vry was van gliadiene. 'n Vereenvoudigde een-dimensionele metode van Singh et al (1991) is gebruik. Die HMW en LMW gluteniene is op 'n enkele gel geëvalueer. b) Die F2:3 ontwikkelde lyne van agt verskillende Tugela kruising is geëvalueer vir broodbakkwaliteit deur gebruik te maak van die metodes van die "American Association of Cereal Chemists" (AACC). 3 Die resultate was as volg: a) Slegs vier persent uit die F2 nageslagte van die agt Tugela kruisings, het geen bande op die A genoom bevat nie. b) Meer as een bandpatroon is terselfdetyd uitgedruk in die F2 nageslag en in suiwertelende cultivars. Dit was kontrasterend met die bevindinge van Gupta en Shepherd (1990b). Hulle het bevind dat slegs een bandpatroon op elke chromosoom in In suiwertelende cultivar uitgedruk word. c) As gevolg van interaksies tussen ouertipes word nuwe bandpatrone gevorm deur middel van rekombinasie. d) Sekere kultivars het geen ooreenstemmende bandpatrone op die B- en Dgenome getoon nie. Polimorfismes is algemeen in koring en nuwe bandkombinasies is moontlik. e) Dit wil voorkom of daar geen van die normale oorerflikheidspatrone (kodominansie) gevolg is nie, maar dat daar eerder In tipe van onderdrukking van bandpatrone in die F2 lyne was. f) Die kwaliteit resultate het baie verskille tussen die Tugela kruisings en Tugela getoon. Dit was alreeds moontlik om in die vroeë generasies In verbetering in die stabiliteit (minder oorstabiel) in die deeg waar te neem. g) Die kompleksiteit van die LMW-GS het dit bemoeilik om sekere LMW glutenien patrone met sekere kwaliteits parameters te korreleer. 4. Die volgende afleidings kan gemaak word: a) Die oorerflikheid van LMW gluteniene in Suid-Afrikaanse koringmateriaal is baie meer kompleks as wat verwag is. b) Die Suid-Afrikaanse materiaal het nie altyd die oorerflikheidspatrone en bandpatrone gevolg soos voorgeskryf deur die nomenklatuur van Gupta en Shepherd (1990b) nie. c) Die verskille in LMW glutenien samestelling moet die verskille in broodbakkwaliteit verduidelik, want daar was min tot geen verskille in die samestelling van die HMW gluteniene nie. d) Vroeë generasie kwaliteitstoetse (F2:3) kon alreeds 'n aanduiding gee van die vordering wat gemaak is in die verbetering van die broodbakkwaliteit. e) Die onverwagse segregasie patrone tesame met die veelvudige uitdrukking van kombinasies in die F2 qenerasies sal merkerondersteunde seleksie op grond van LMW gluteniene moeilik maak in die vroeë stadium. f) Die bydrae van ouers tot die LMW gluteniene was so divers, dat nie een bandpatroon geïdentifiseer kon word, wat spesifieke bakkwaliteits eienskappe beïnvloed nie. g) Totdat die nomenklatuur sisteem van Gupta en Shepherd (1990b) opgegradeer is met die moontlike uniek Suid-Afrikaanse LMW glutenien patrone, sal die korrelasie van LMW glutenien data met kwaliteits resultate baie moeilik wees.
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Plant proteins, Wheat genetics, Wheat -- Breeding -- South Africa, Dissertation (M.Sc. Agric. (Plant Breeding))--University of the Free State, 2001
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