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MD Dating – Dating of wood based on its molecular decay (MD) measured using FTIR spectroscopy
Get PDFEstablishment of a field spectral library of agricultural crops in Germany for monitoring biophysical parameters at different spatial scales
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Spatiotemporal chemical cartography of plant cell wall dynamics during growth and after gravitropic stress
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Locating QTL conferring resistance against net blotch, leaf rust, and stripe rust in the wild barley nested association mapping (NAM) population HEB-25
Get PDFNet blotch, caused by the fungus Pyrenophora teres f. teres, Puccinia hordei, causing leaf rust, and Puccinia striiformis f. sp. hordei, the causal agent of stripe rust, are important fungal diseases of barley with the potential to cause severe yield losses and a reduction in feed and malting quality. The identification of QTL conferring resistance is the basis for targeted breeding approaches aiming to improve resistance of modern barley cultivars against these fungi. Initial domestication from its wild progenitor Hordeum vulgare subsp. spontaneum and extensive breeding resulted in a loss of genetic diversity in modern elite barley varieties. Many modern barley varieties are similar in their genotype resulting in an increased risk of occurrence of severe epidemics. There is an urgent need to broaden the genetic basis of resistance of modern barley cultivars to ensure a stable production. Wild barley accessions possessing high allelic richness have shown to be a valuable source of resistance alleles no longer present in the current breeding pool. In the framework of this thesis, the NAM population HEB-25 was utilized to detect QTL conferring resistance against net blotch, leaf rust, and stripe rust. Screening of HEB-25 in two-year field trials revealed the presence of a high genetic diversity within HEB-25 and allowed for the identification of HEB-lines with a high degree of resistance to one or more of the evaluated fungi. NAM applying the 9k iSelect barley chip performed independently for all three fungi resulted in the identification of a high number of QTL conferring resistance on all chromosomes with predominantly small effect. In case of net blotch six QTL, eight QTL for stripe rust and two QTL for leaf rust, are considered novel showing no overlap with previously reported resistance QTL. Estimation of parent-specific QTL effects indicates the presence of alleles with increasing or decreasing effect on genotype resistance, respectively. Leucine-rich repeat, NB-ARC, and serine/threonine-protein kinase-like genes were found at high frequency in the QTL intervals and due to their important role in plant defense response represent putative candidate genes causing the QTL effect. HEB-25 showed to be well suited for the detection of QTL conferring resistance to net blotch, leaf rust, or stripe rust and represents a valuable source for improving genetic diversity and resistance of modern barley cultivars against these fungi.Net blotch, caused by the fungus Pyrenophora teres f. teres, Puccinia hordei, causing leaf rust, and Puccinia striiformis f. sp. hordei, the causal agent of stripe rust, are important fungal diseases of barley with the potential to cause severe yield losses and a reduction in feed and malting quality. The identification of QTL conferring resistance is the basis for targeted breeding approaches aiming to improve resistance of modern barley cultivars against these fungi. Initial domestication from its wild progenitor Hordeum vulgare subsp. spontaneum and extensive breeding resulted in a loss of genetic diversity in modern elite barley varieties. Many modern barley varieties are similar in their genotype resulting in an increased risk of occurrence of severe epidemics. There is an urgent need to broaden the genetic basis of resistance of modern barley cultivars to ensure a stable production. Wild barley accessions possessing high allelic richness have shown to be a valuable source of resistance alleles no longer present in the current breeding pool. In the framework of this thesis, the NAM population HEB-25 was utilized to detect QTL conferring resistance against net blotch, leaf rust, and stripe rust. Screening of HEB-25 in two-year field trials revealed the presence of a high genetic diversity within HEB-25 and allowed for the identification of HEB-lines with a high degree of resistance to one or more of the evaluated fungi. NAM applying the 9k iSelect barley chip performed independently for all three fungi resulted in the identification of a high number of QTL conferring resistance on all chromosomes with predominantly small effect. In case of net blotch six QTL, eight QTL for stripe rust and two QTL for leaf rust, are considered novel showing no overlap with previously reported resistance QTL. Estimation of parent-specific QTL effects indicates the presence of alleles with increasing or decreasing effect on genotype resistance, respectively. Leucine-rich repeat, NB-ARC, and serine/threonine-protein kinase-like genes were found at high frequency in the QTL intervals and due to their important role in plant defense response represent putative candidate genes causing the QTL effect. HEB-25 showed to be well suited for the detection of QTL conferring resistance to net blotch, leaf rust, or stripe rust and represents a valuable source for improving genetic diversity and resistance of modern barley cultivars against these fungi
HPLC-PDA-ESI-MSn profiling of polyphenolics in different parts of Capparis spinosa and Capparis decidua as function of harvesting seasons
Get PDFHPLC-PDA-ESI-MSn analysis of different parts such as stem bark, shoot, flower, fruit and root of Capparis spinosa (C. spinosa) and Capparis decidua (C. decidua), collected in rainy and dry seasons from the Cholistan desert of Pakistan, depicted the occurrence of a wide array of phenolics with quercetin, apigenin and kaempferol derivatives along with dicaffeoylquinic acid, caffeoylquinic acid and feruloylquinic acid as the main compounds. Kaempferol-3-glucoside (28.02-167.21 μg g-1dw) was found to be the principal component in all tested parts of both species while dicaffeoylquinic acid was detected only in the flowers and roots. The roots exhibited maximum contents of flavonoids and hydroxycinnamic acid derivatives. The harvesting period significantly (p<0.05) affected the concentration of phenolics wherein the samples collected in rainy season offered greater levels of phenolics than their counterpart. The roots and fruits of both species were found to be rich sources of phenolics. The findings of this research suggest the harvesting of the selected wild Capparis species in rainy season to maximize their antioxidant and nutraceutical benefits
Sodium in the leaf apoplast does not affect growth of maize (Zea mays L.) under saline field conditions
Get PDFStudies dealing with leaf apoplastic Na+ concentration of monocots, such as maize, under actual saline soils are scarce. Therefore, the current study was aimed to investigate the growth, total ions and leaf apoplastic Na+ concentration of salt sensitive maize plants growing in saline soils. Plants were subjected to salt stress with an electrical conductivity (EC) of 3, 8 10 and 14 dS m-1 using completely randomized design (CRD) for 3 weeks. Shoot fresh weight, plant height, leaf area and leaf length of maize plants drastically decreased when plants were exposed to increasing salt stress. We found that maize could display a steep increase in Na+ concentration in the total shoot biomass with maximum 82.3 μmol g-1 FW, when plants were subjected to highest soil salinity at 14 dS m-1. As expected, other cations i.e., K+, Ca2+ and Mg2+ decreased with increasing EC of the soil compared to Na+. Surprisingly, a maximum of 17 mM Na+ were found in the leaf apoplast of maize grown under very high soil salinity at EC 14 dS m-1. Considering this lower leaf apoplastic Na+ concentration at such a high EC level in maize plants, current study does not corroborate that surplus sodium in the leaf apoplast can result in dehydration and cell death under salt stress
Hybridization between Pelargonium acetosum L’Hér. and Pelargonium xpeltatum
Get PDFPelargonium acetosum L’Hér. is a wild species from South Africa with decorative bluish foliage. Only few reports describe crossings between P. acetosum and P. peltatum L’Hér. (or P. ×peltatum). Therefore, information about hybridization barriers is limited. In this study, two different genotypes of Pelargonium acetosum (AC1 and AC2) were crossed with the diploid P. ×peltatum ‘Tornado Fuchsia’ (PTF). Embryos and F1 hybrids from the combination AC1 × PTF were hampered by chlorophyll deficiencies. Embryos and seeds of the combination AC2 × PTF were underdeveloped. The reciprocal combination PTF × AC1 did not show any fruit set. The combination PTF × AC2 resulted in low numbers of seeds, which were normally developed. Hybrids from seeds were only obtained from the combinations AC1 × PTF and PTF × AC2. Embryo rescue of the combinations AC1 × PTF and AC2 × PTF resulted in few but viable hybrids. Flowers of all hybrids had shrivelled anthers and proved to be sterile. The occurrence of most hybridization barriers varied strongly between the different combinations and depended on both the genotype and the direction of cross-breeding. The bluish leaf colour did not appear among the F1. To overcome hybrid sterility a polyploidization is suggested