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

[摘要] ENGLISH ABSTRACT: The international demand for wheat production is placing pressure on breeders toincrease 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 % ofglobal 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 wheatgrowing 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 pyramidFHB 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 thesegregating 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 resistancehave on the bread baking properties. Phenotyping the presence of rust and FHB QTL through inoculating the population with rust and fusarium isolates.

[发布机构] Stellenbosch University