Investigation of soil bioactivity and weed infestation in spring oilseed rape agrocoenosis of different density Aušra Grybaitė Field experiments were carried out in 2004 and 2005 at the Experimental Station of Lithuanian University of Agriculture to study the influence of different spring oilseed rape (Brassica napus L.) ‘Sponsor’ densities (50.1-100, 100.1-150, 150.1-200, 200.1-250, 250.1-300, 300.1-350, 350.1-400, 400.1-450 plants m-2) on soil bioactivity and weed infestation. Soil - Calc(ar)i-Endohypogleyic Luvisol. By increasing of spring oilseed rape crop urease activity in the soil didn’t chage significantly. The saccharase activity in the rape agrocoenosis with density more than 150.1 plants m-2 significantly increased in comparison with saccharase activity in the thinest rape agrocoenosis. The content of humus (r = 0.73, P < 0.05) and available phosphorus (r = 0.71, P < 0.05) influenced the saccharase activity. Spring oilseed rape crop density had no influence on number of weed species, weed sprouts and weed density before harvest. Efficiency of weed suppressing increased when weed density in crop at 3-4 leaves stage increased. This proved the small similarity indexes of weed density in crop at 3-4 leaves stage and before harvest. Rape crop density had no influence on weed species change. Significant negative relationship was found between weed air-dry biomass and rape crop density (r = -0.82, P < 0.01). Most of weeds in rape crop were therophytes. Most of them... [to full text]

Seed-placed phosphorus (P) and sulphur (S) fertilizers can reduce canola plant stands. Field studies were conducted to determine the effect of various sources and rates of seed-placed P and S fertilizers on canola plant stand, early season biomass accumulation and seed yield. Conventional granular P and S blends increased the risk of seedling damage, but increased the frequency of yield response. Liquid fertilizers were similar in seedling damage but generally less effective in increasing seed yield compared to granular fertilizers. Novel fertilizers were more seed-safe but less reliable than conventional sources in increasing seed yield. A growth room experiment was conducted to determine the effect of soils from different landscape positions on the toxicity of seed-placed ammonium sulphate (AS) and monoammonium phosphate (MAP). Canola emergence was reduced and delayed by seed-placed MAP and AS. Ammonium sulphate in particular has a high risk of NH3 toxicity on calcareous hilltop soils

Molecular markers for seed quality traits including erucic acid content genes, seed coat color genes in Brassica napus and seed coat color genes in B. rapa were developed. A single base change in the Bn-FAE1.1 gene in the A genome and a two-base deletion in the Bn-FAE1.2 gene in the C genome produce the nearly zero content of erucic acid observed in canola. The single base change was detected as single nucleotide polymorphic (SNP) marker with an ABI SNaPshot kit. A multiplexing primer set was designed by adding a polyT to the 5´ primer end to increase SNP detection throughput through sample pooling. The two-base deletion in the C genome gene was detected as a sequence characterized amplified region (SCAR) marker in an ABI 3100 Genetic analyzer. To increase the throughput, one genome specific primer was labeled with four fluorescence dyes and combined with 20 different primers to produce PCR products with different fragment sizes. These multiplexed high throughput molecular markers have been successfully implemented in our canola/rapeseed breeding programs. Trigenic inheritance was observed for seed coat color in B. napus. Three Sequenced Related Amplified Polymorphism (SRAP) markers very closely linked to the three different seed coat color genes were developed. Chromosome-walking technology was used to convert the SRAP marker into a SCAR marker and a SNP marker. Subsequently, the first seed coat color gene (Bn1) marker was converted into a SCAR marker, and the second seed coat color gene (Bn2) marker was converted into a SNP marker. Digenic inheritance was observed for seed coat color genes in B. rapa. A SRAP marker was identified as being tightly linked to the major seed coat color gene (Br1). The SRAP marker was sequenced and extended sequences were obtained using chromosome-walking technology. The flanking sequences of the SRAP marker contained 24 SNPs and a 12-bp deletion position that allowed the marker to be converted into a co-dominant SNP marker and a co-dominant SCAR marker, respectively. The SCAR marker was detected in the ABI 3100 genetic analyzer with four fluorescently labeled M13 primers integrated with different SCAR primers, which permitted pooling of PCR samples for high throughput detection.

Brassica napus is grown as an edible oil (canola) and an industrial oil (HEAR). Its fatty acid profile and chlorophyll concentration affect the quality. It is important to develop accurate and efficient methods to evaluate these traits. The first objective of this study was to improve the single nucleotide polymorphism (SNP) and sequence characterized amplified region (SCAR) molecular markers for erucic acid genotypes in the Bn-FAE1.1 and Bn-FAE1.2 genes in the A and C genomes in Brassica napus originally developed by Rahman et al. (2008). When put into practice, the error rate was unacceptably high. With the modifications that were made to the protocols, the overall accuracy remained relatively consistent indicating that further improvements are still required. The second objective was to develop a near infrared reflectance (NIR) based calibration equation for chlorophyll concentration in whole Brassica napus seeds. In this case, an equation was successfully created.

Consistency of yield and quality of seed are traits not yet optimised by the brassica seed industry in New Zealand. As of 2008, seed producers in Canterbury, New Zealand, exported approximately $18m of brassica seed. However, there is a need to increase both seed quantity and/or quality. The plant hormone group, the cytokinins, regulates many stages of plant growth and development, including cell division and enhancement of sink strength, both of which are important processes in seed development and embryonic growth. The two gene families targeted in this project play a key role in maintaining cytokinin homeostasis. Isopentenyl transferase (IPT) catalyzes the rate limiting step in the formation of cytokinins, and cytokinin oxidase/dehydrogenase (CKX) irreversibly inactivates cytokinins. The aim of this project was to identify those cytokinin gene family members expressing specifically during the early phases of pod and seed development. Initially this study used a rapid-cycling Brassica rapa (RCBr) because of its rapid life cycle, then, as the project developed, a commercial crop of forage brassica (B. napus) was studied. Reverse transcriptase PCR (RT-PCR) and BLAST analysis was used to identify putative IPT and CKX genes from RCBr and B. napus. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to measure the expression of individual gene family members during leaf, flower, pod and seed development. BrIPT1, -3, and -5, and BrCKX1, -2, -3, and -5/7 and were shown to express differentially both temporally and spatially within RCBr root, stem, leaf, seed, and pod tissues. BnIPT1, 3 and 7 and BnCKX1, 2, 5 and 7 were also differentially expressed. Particularly strong expression was shown by BrIPT3, BrIPT5 and BrCKX2 in developing seeds. Both Brand BnIPT3 expressed strongly in maturing leaves. In normal plant growth and development, biosynthesis and metabolism of cytokinin is tightly regulated by the plant. Increasing the levels of cytokinins during seed development, either by over expressing IPT3 or IPT5, or decreasing the expression of CKX2, or both, could potentially increase both seed yield and seed vigour.

Durch eine Erhöhung der Diversität in Kandidatengenen für Ölgehalt könnten sich neue Ansätze zur Erhöhung des Ölgehalts ergeben (Osborn et al., 2007; Würschum et al., 2013). Im Rahmen dieser Arbeit wurde die allele Diversität auf der Basis von DNA-Sequenzen in einer großen Anzahl von Kandidatengenloci für Ölgehalt in exotischem Rapsmaterial (Sommerrapssorten, chinesische Rapssorten und Resynthesen) im Vergleich zu Winterraps untersucht. Viele Allele wurden exklusiv in den exotischen Genotypen aufgefunden (neue Allele). Die höchste Anzahl an neuen Allelen wurde in der Resynthese “MOY4“ (Brassica rapa var. trilocularis x Brassica montana) entdeckt. Viele der Allele wiesen SNP, die zu Aminosäureaustauschen führen, sowie InDel im kodierenden Bereich der untersuchten Kandidatengenloci auf. Einige dieser Polymorphismen konnten sogar Bereichen von Proteindomänen zugeordnet werden. Im Großen und Ganzen konnte in der durchgeführten Diversitätsstudie gezeigt werden, dass die untersuchten exotischen Genotypen genutzt werden können, um die allele Diversität in Kandidatengenen für Ölgehalt zu erhöhen. Zudem weist die relativ hohe Anzahl an nicht stillen Polymorphismen in den kodierenden Bereichen der verschiedenen Kandidatengenloci darauf hin, dass einige aufgefundene Allele den Ölgehalt beeinflussen könnten. Um einen möglichen positiven Einfluss von neuen Allelen in Kandidatengenen für Ölgehalt auf den Ölgehalt zu testen, wurden diese in spaltenden F2-Populationen an jeweils drei verschiedenen Standorten untersucht. In diesem Versuch wurden neue Allele, die in der durchgeführten Diversitätsstudie entdeckt wurden, sowie neue Allele, welche bereits in dem vorigen GABI BRIDGE Projekt aufgefunden wurden, mittels Varianzanalyse auf eine Auswirkung auf den Ölgehalt getestet. In einzelnen Populationen konnten signifikante Geneffekte auf den 87 Ölgehalt an drei verschiedenen Kandidatengenloci ermittelt werden: S13 (Kandidatengen KAS III), K48 (Kandidatengen PKP2), L65 (Kandidatengen LEC2). Einzel-Locus-Genotyp x Umweltinteraktionen mit einem signifikanten Effekt auf Ölgehalt wurden an sechs Kandidatengenloci inklusive S13 von KAS III aufgefunden. Diese aufgefundenen signifikanten Effekte auf den Ölgehalt können als deutlicher Hinweis auf die Wichtigkeit der untersuchten Loci beziehungsweise des Alleles auf den Ölgehalt interpretiert werden.

Seed-placed phosphorus (P) and sulphur (S) fertilizers can reduce canola plant stands. Field studies were conducted to determine the effect of various sources and rates of seed-placed P and S fertilizers on canola plant stand, early season biomass accumulation and seed yield. Conventional granular P and S blends increased the risk of seedling damage, but increased the frequency of yield response. Liquid fertilizers were similar in seedling damage but generally less effective in increasing seed yield compared to granular fertilizers. Novel fertilizers were more seed-safe but less reliable than conventional sources in increasing seed yield. A growth room experiment was conducted to determine the effect of soils from different landscape positions on the toxicity of seed-placed ammonium sulphate (AS) and monoammonium phosphate (MAP). Canola emergence was reduced and delayed by seed-placed MAP and AS. Ammonium sulphate in particular has a high risk of NH3 toxicity on calcareous hilltop soils

Molecular markers for seed quality traits including erucic acid content genes, seed coat color genes in Brassica napus and seed coat color genes in B. rapa were developed. A single base change in the Bn-FAE1.1 gene in the A genome and a two-base deletion in the Bn-FAE1.2 gene in the C genome produce the nearly zero content of erucic acid observed in canola. The single base change was detected as single nucleotide polymorphic (SNP) marker with an ABI SNaPshot kit. A multiplexing primer set was designed by adding a polyT to the 5´ primer end to increase SNP detection throughput through sample pooling. The two-base deletion in the C genome gene was detected as a sequence characterized amplified region (SCAR) marker in an ABI 3100 Genetic analyzer. To increase the throughput, one genome specific primer was labeled with four fluorescence dyes and combined with 20 different primers to produce PCR products with different fragment sizes. These multiplexed high throughput molecular markers have been successfully implemented in our canola/rapeseed breeding programs. Trigenic inheritance was observed for seed coat color in B. napus. Three Sequenced Related Amplified Polymorphism (SRAP) markers very closely linked to the three different seed coat color genes were developed. Chromosome-walking technology was used to convert the SRAP marker into a SCAR marker and a SNP marker. Subsequently, the first seed coat color gene (Bn1) marker was converted into a SCAR marker, and the second seed coat color gene (Bn2) marker was converted into a SNP marker. Digenic inheritance was observed for seed coat color genes in B. rapa. A SRAP marker was identified as being tightly linked to the major seed coat color gene (Br1). The SRAP marker was sequenced and extended sequences were obtained using chromosome-walking technology. The flanking sequences of the SRAP marker contained 24 SNPs and a 12-bp deletion position that allowed the marker to be converted into a co-dominant SNP marker and a co-dominant SCAR marker, respectively. The SCAR marker was detected in the ABI 3100 genetic analyzer with four fluorescently labeled M13 primers integrated with different SCAR primers, which permitted pooling of PCR samples for high throughput detection.

Brassica napus is grown as an edible oil (canola) and an industrial oil (HEAR). Its fatty acid profile and chlorophyll concentration affect the quality. It is important to develop accurate and efficient methods to evaluate these traits. The first objective of this study was to improve the single nucleotide polymorphism (SNP) and sequence characterized amplified region (SCAR) molecular markers for erucic acid genotypes in the Bn-FAE1.1 and Bn-FAE1.2 genes in the A and C genomes in Brassica napus originally developed by Rahman et al. (2008). When put into practice, the error rate was unacceptably high. With the modifications that were made to the protocols, the overall accuracy remained relatively consistent indicating that further improvements are still required. The second objective was to develop a near infrared reflectance (NIR) based calibration equation for chlorophyll concentration in whole Brassica napus seeds. In this case, an equation was successfully created.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.