Improvement of rust resistance and FHB resistance QTL in wheat through the application of an integrated biotechnology approach

Meintjes, Schalk Willem (2017-03)

Thesis (MSc)--Stellenbosch University, 2017.

Thesis

ENGLISH ABSTRACT: The international demand for wheat production is placing pressure on breeders to increase and develop elite cultivars which are adapted to meet specific criteria such as high grain quality and high yield potential (Francki and Appels, 2002). Unfortunately these cultivation and agronomical demands are not the only factor for breeders to think about when it comes to food security. More specifically, abiotic and biotic stressor influence food security significantly. Each year 10-16 % of global harvest is lost due to plant diseases (Oerke, 2006). Based on a Molecular Plant Pathology survey taken in 2012, the top 10 fungal pathogens affecting crop production was taken and Puccinia species where listed third, followed by Fusarium graminearum (FHB) in fourth place (Dean et al., 2012). The wheat rust fungi (leaf, stem and stripe rust) have become economical important diseases worldwide. Puccinia have the ability to mutate, migrate and recombinate, these abilities are predominantly the reason why wheat rust epidemics are a serious concern in wheat growing areas around the world (Sing et al., 2002). FHB occurs in a number of wheat growing regions (Asia, Australia, Canada, Kenya, Europe, North and South America and South Africa) (Waalwjik et al., 2003; Guo et al., 2008; Karugia et al. 2009). The first FHB report on wheat in South Africa was in 1980 in the North-West Province (Scott et al., 1988). FHB produces mycotoxins that contaminate grain, causing lower yield and quality (Leonard and Bushnell, 2003). The challenge however is to pyramid FHB QTL and rust genes into one cultivar for durable resistance. The aim of the study was to pyramid rust genes and FHB QTL in to one genotype by performing the male sterility mediated marker assisted recurrent selection scheme (MS-MARS). A segregating F1 population was provided for the MS-MARS cycle 1 from an existing pre-breeding nursery. Molecular markers were successfully implemented to determine the gene frequenciesof rust genes (Sr2, Sr31, Sr24, Sr26, Lr34,Lr37 and Lr19) in the segregating F1 population. The cross was between a rust male donor and a FHB male donor population to produce two independent subpopulations in MS-MARS cycle 1. The gene frequencies of the rust male donors were known. The gene frequencies of the FHB male donor population were successfully determined through molecular characterization. The FHB QTL of interest was (Qfhs.ifa-5A, 7AQTL and Qfhs.ndsu-3BS). The gene frequencies of 40 %, 92 %, 0.8 %, 48 %, 1.68 %, 69 % and 9.45 % were observed for Sr2, Sr24, Sr26, Sr31, Lr19, Lr34 and Lr37 respectively in the segregating F1 base population of cycle 1. The gene frequencies of 83.30 %, 17 % and 66.67 % were observed for Qfhs.ndsu-3BS, 7A QTL and Qfhs.ndsu-5A-1 respectively in the FHB male donor population. Future studies will include the development of a double haploid population with pyramided rust genes and FHB resistant QTL. Determine the effect FHB resistance have on the bread baking properties. Phenotyping the presence of rust and FHB QTL through inoculating the population with rust and fusarium isolates.

AFRIKAANSE OPSOMMING: Die internasionale aanvraag na koringproduksie plaas druk op koringtelers vir ‘n toename en die ontwikkeling van elite kultivars wat aangepas is om hoër graankwaliteit en opbrengste te lewer (Francki en Appels, 2002). Ongelukkig is die vraag na hoër en beter koringopbrengste nie die enigste probleem vir telers as dit kom by voedselsekuriteit nie. Meer spesifiek, abiotiese en biotiese faktore speel ook ‘n beduidende rol in voedselsekuriteit. Elke jaar word 10-16 % van die wêreld se koring produksie gekelder deur plantsiektes (Oerke, 2006). ‘n Molekulêre Plant Patologiese opname in 2012, het aangedui dat ten opsigte van die top 10 patogene wat gewasproduksie benadeel, Puccinia species was algeheel in die derde plek, gevolg deur Fusarium graminearum (FHB) in die vierde plek (Dean et al., 2012). Die koringroes swamme (blaar-, stam- en streep-roes) het ‘n ekonomiese belangrike siekte geword wêreldwyd. Puccinia besit die vermoë om te muteer, migreer en te kan rekombineer. Hierdie vaardighede is hoofsaaklik die rede hoekom koringroes epidemies so ‘n ernstige probleem is in die koringproduksie areas regoor die wêreld (Singh et al., 2002). FHB kom voor in verskeie koring produksie streke (Asië, Australië, Kanada, Kenya, Europa, Noord en Suid Amerika en Suid-Afrika) (Waalwjik et al., 2003; Guo et al., 2008; Karugia et al. 2009). Fusarium is vir die eerste keer op koring in Suid-Afrika waargeneem gedurende 1980 in die Noord-Wes Provinsie (Scott et al., 1988). FHB vervaardig mikotoksiene wat koring kontamineer en so doende die kwaliteit en obrengs verlaag (Leonard and Bushnell, 2003). Die uitdaging bestaan dus om FHB QTL en roes gene te stapel in een kultivar vir duursame weerstand. Die doel van die studie was om roes gene en FHB QTL te stapel deur die manlike steriele bemiddelde merker assisterende herhalende seleksie skema uit te voer (MS-MARS). ‘n Segregerende F1 populasie was verskaf vir die MS-MARS siklus 1 vanaf ‘n bestaande voor-telende kwekery. Molekulêre merkers was suksesvol geimplimenteer vir die bevestiging van geen frekwensies vir die volgende roes gene (Sr2, Sr31, Sr24, Sr26, Lr34,Lr37 and Lr19) in die segregerende F1 populasie. Die kruisings was tussen ‘n manlike roes donor en manlike FHB donor populasies om twee onafhanklike sub-populasies te produseer in MS-MARS siklus 1. Die manlike roes donor geen frekwensies is bepaal. Slegs die manlike FHB donor geen frekwensies was bepaal deur molekulêrekarakterisering. Die FHB QTL van belang was (Qfhs.ifa-5A, 7AQTL and Qfhs.ndsu-3BS). Die geen frekwensies van 40 %, 92 %, 0.8 %, 48 %, 1.68 %, 69 % and 9.45 % was waargeneem vir Sr2, Sr24, Sr26, Sr31, Lr19, Lr34 and Lr37 respektiewelik vir die segregerende F1 basis populasie van MS-MARS cycle 1. Die geenfrekwensies van 83.30 %, 17 % and 66.67 % was bepaal vir Qfhs.ndsu-3BS, 7A QTL and Qfhs.ndsu-5A- 1 respektiewelik vir die manlike FHB donor populasies. Toekomstige studies sal fokus op die ontwikkeling van verdubbelde haploïdes met gestapelde roes gene en FHB weerstand QTL’s. Evalueer die die effek wat FHB weerstand het op die bak kwaliteit van brood. Bevestig die teenwoordigheid van roes gene en FHB QTL’s deur die populasie te inokuleer met roes- en fusarium isolate.

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