Browsing by Person "Kessel, Bettina"

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Exploiting genetic diversity in two European maize landraces for improving Gibberella ear rot resistance using genomic tools
(2021) Gaikpa, David Sewordor; Kessel, Bettina; Presterl, Thomas; Ouzunova, Milena; Galiano-Carneiro, Ana L.; Mayer, Manfred; Melchinger, Albrecht E.; Schön, Chris-Carolin; Miedaner, Thomas
Fusarium graminearum (Fg) causes Gibberella ear rot (GER) in maize leading to yield reduction and contamination of grains with several mycotoxins. This study aimed to elucidate the molecular basis of GER resistance among 500 doubled haploid lines derived from two European maize landraces, “Kemater Landmais Gelb” (KE) and “Petkuser Ferdinand Rot” (PE). The two landraces were analyzed individually using genome-wide association studies and genomic selection (GS). The lines were genotyped with a 600-k maize array and phenotyped for GER severity, days to silking, plant height, and seed-set in four environments using artificial infection with a highly aggressive Fg isolate. High genotypic variances and broad-sense heritabilities were found for all traits. Genotype-environment interaction was important throughout. The phenotypic (r) and genotypic (rg) correlations between GER severity and three agronomic traits were low (r= − 0.27 to 0.20; rg = − 0.32 to 0.22). For GER severity, eight QTLs were detected in KE jointly explaining 34% of the genetic variance. In PE, no significant QTLs for GER severity were detected. No common QTLs were found between GER severity and the three agronomic traits. The mean prediction accuracies (p) of weighted GS (wRR-BLUP) were higher than p of marker-assisted selection (MAS) and unweighted GS (RR-BLUP) for GER severity. Using KE as the training set and PE as the validation set resulted in very low p that could be improved by using fixed marker effects in the GS model.
Intercontinental trials reveal stable QTL for Northern corn leaf blight resistance in Europe and in Brazil
(2020) Galiano-Carneiro, Ana L.; Kessel, Bettina; Presterl, Thomas; Miedaner, Thomas
Northern corn leaf blight (NCLB) is one of the most devastating leaf pathogens in maize (Zea mays L.). Maize cultivars need to be equipped with broad and stable NCLB resistance to cope with production intensification and climate change. Brazilian germplasm is a great source to increase low NCLB resistance levels in European materials, but little is known about their effect in European environments. To investigate the usefulness of Brazilian germplasm as NCLB resistance donors, we conducted multi-parent QTL mapping, evaluated the potential of marker-assisted selection as well as genome-wide selection of 742 F1-derived DH lines. The line per se performance was evaluated in one location in Brazil and six location-by-year combinations (= environments) in Europe, while testcrosses were assessed in two locations in Brazil and further 10 environments in Europe. Jointly, we identified 17 QTL for NCLB resistance explaining 3.57–30.98% of the genotypic variance each. Two of these QTL were detected in both Brazilian and European environments indicating the stability of these QTL in contrasting ecosystems. We observed moderate to high genomic prediction accuracies between 0.58 and 0.83 depending on population and continent. Collectively, our study illustrates the potential use of tropical resistance sources to increase NCLB resistance level in applied European maize breeding programs.
Multi-parent QTL mapping reveals stable QTL conferring resistance to Gibberella ear rot in maize
(2021) Galiano-Carneiro, Ana L.; Kessel, Bettina; Presterl, Thomas; Gaikpa, David Sewordor; Kistner, Maria Belen; Miedaner, Thomas
Maize production is on risk by Gibberella ear rot (GER) caused by Fusarium graminearum. This is one of the most important ear rot diseases in temperate zones as it leads to yield losses and production of harmful mycotoxins. We investigated, for the first time, the potential use of Brazilian tropical maize to increase resistance levels to GER in temperate European flint germplasm by analyzing six interconnected biparental populations. We assessed GER symptoms in Brazil and in Europe in up to six environments (= location × year combinations) during the growing seasons of 2018 and 2019. We conducted multi-parent QTL and biparental QTL mapping, and identified four QTLs with additive gene action, each explaining 5.4 to 21.8% of the total genotypic variance for GER resistance. Among them, QTL q1 was stable across test environments, populations, and between inbred lines and testcrosses. The accuracies of genomic prediction ranged from 0.50 to 0.59 depending on the resistance donor and prediction model. Jointly, our study reveals the potential use of Brazilian resistance sources to increase GER resistance levels by genomics-assisted breeding.
Multi‐parental QTL mapping of resistance to white spot of maize (Zea mays) in southern Brazil and relationship to QTLs of other foliar diseases
(2021) Kistner, María Belén; Galiano‐Carneiro, Ana Luísa; Kessel, Bettina; Presterl, Thomas; Miedaner, Thomas
Maize white spot (MWS) is one of the most important foliar diseases in Brazil causing significant yield losses. Breeding genotypes with MWS resistance is the most sustainable alternative for managing such losses; however, their genetic control is poorly understood. Our objectives were to identify genomic regions controlling MWS resistance and to explore the presence of common regions controlling resistance to MWS, grey leaf spot (GLS) and northern corn leaf blight (NCLB). We performed a multi‐parental QTL mapping for MWS and GLS resistance with a total of 474 testcrosses and phenotypic data collected in southern Brazil. Six QTLs for MWS resistance on bins 1.03, 1.04, 6.02, 8.05, 1.03, and 10.06 were detected. These findings were compared with previously reported QTLs for NCLB in the same populations, and a common QTL region (bin 8.05) controlling MWS and NCLB resistances was identified. Our findings contribute to a better understanding of MWS resistance by revealing three QTLs (bin 6.02, 1.03, and 10.06), to the best of our knowledge, not yet described in the literature, that are valuable for improving MWS resistance and one promising candidate region for multiple disease resistance.