1,721,084 research outputs found
Geographic pattern of genetic diversity among 43 Ethiopian Mustard(Brassica carinata A. Braun) accessions as revealed by RAPD analysis
No full textAs an oilseed crop, the cultivation of Ethiopian mustard (Brassica carinata) is restricted only to Ethiopia. Even though geographic diversity is a potent source of allelic diversity, the extent of genetic diversity among germplasm material of Ethiopian mustard from different countries has not been assessed. Forty-three accessions, comprising 29 accessions from eight different geographic regions of Ethiopia and 14 exotic accessions from Australia, Pakistan, Spain, and Zambia were analysed for their genetic diversity using random amplified polymorphic DNA (RAPD) technique. A set of 50 primers yielded a total of 275 polymorphic bands allowing an unequivocal separation of every Ethiopian mustard accession. The usefulness of the 50 RAPD primers in measuring heterozygousity and distinguishing accessions was variable such that polymorphic information content (PIC) varied from 0.05 to 0.40, band informativeness (BI) from 0.05 to 0.65 and primer resolving power (RP) from 0.15 to 6.83. Jaccard's similarity coefficients ranged from 0.44 to 0.87 indicating the presence of a high level of genetic diversity. On the average, Australian and Ethiopian accessions were the most similar while, Spanish and Zambian accessions were the most distant ones. Cluster analysis grouped the 43 accessions into four groups, which has quite a high fit (r = 0.80) to the original similarity matrix. With no prior molecular information, the RAPD technique detected large genetic diversity among the 43 accessions from five different countries and their grouping by dendrogram and principal coordinate analysis (PCoA) was inclined towards geographic differentiation of RAPD markers. Conversely, RAPD differentiation along geographic origin was not apparent within the Ethiopian accessions
Genetic analysis of heterosis for yield and yield components in rapeseed (Brassica napus L.) by quantitative trait locus mapping
No full textThe main objective in this research was the genetic analysis of heterosis in rapeseed at the QTL level. A linkage map comprising 235 SSR and 144 AFLP markers covering 2045 cM was constructed in a doubled-haploid population from a cross between the cultivar "Express" and the resynthesized line "R53." In field experiments at four locations in Germany 250 doubled-haploid (DH) lines and their corresponding testcrosses with Express were evaluated for grain yield and three yield components. The heterosis ranged from 30% for grain yield to 0.7% for kernel weight. QTL were mapped using three different data sets, allowing the estimation of additive and dominance effects as well as digenic epistatic interactions. In total, 33 QTL were detected, of which 10 showed significant dominance effects. For grain yield, mainly complete dominance or overdominance was observed, whereas the other traits showed mainly partial dominance. A large number of epistatic interactions were detected. It was concluded that epistasis together with all levels of dominance from partial to overdominance is responsible for the expression of heterosis in rapeseed
Glucosinolates and other seed quality traits of resynthesized Brassica napus L. derived from domesticated and wild Brassica taxa
No full textResynthesized Brassica napus L. genotypes can be used to increase the variation in the rapeseed genepool. We evaluated seed quality parameters of resynthesized lines that originated from crosses of oilseed B. rapa L. with domesticated (vegetable) B. oleracea L., and resynthesized lines that were obtained from crosses of B. rapa oilseed cultivars with wild B. oleracea ssp. oleracea and with seven Brassica species from the B. oleracea group (B. bourgeaui Kuntze, B. cretica Lam., B. incana Ten., B. hilarionis Post, B. montana Pourret, B. rupestris Raf., B. villosa Bivona-Bernardi). Twenty-three resynthesized lines and ten cultivars were grown in 1 year and six locations in Germany and the United Kingdom. The mean seed oil, phytosterole, and sinapine contents of the resynthesized lines were lower than in the cultivars, while protein, glucosinolate, and erucic acid contents were higher, respectively. Nearly all resynthesized lines derived from wild Brassica taxa showed a glucosinolate pattern very different from all cultivars and from nearly all resynthesized lines obtained from crosses with domesticated B. oleracea. The newly developed wild Brassica based resynthesized lines represent an immense source of genetic variation that has not been used to full capacity up to now
Effect of full‐sib and S2‐selection on a sweet corn population (Zea mays convar. saccharata)
No full textAbstract Sweet corn breeding goals differ from grain or silage corn. Sweet corn goals focus on marketable yield including several quality traits. This study explores the effect of a single cycle of full‐sib selection and S2 selection on improving the marketable yield of an open‐pollinated sweet corn population. The selected populations were subsequently compared in four environments for several plant‐, yield‐ and quality traits relative to the original population. Analysis of variance was used to detect selection progress and indirect effects of selection. Full‐sib and S2‐selection decreased total yield. Marketable yield was decreased more by S2‐selection than by full‐sib selection. Flowering time was changed by full‐sib selection, but not by S2‐selection. Full‐sib selection improved ear quality by increasing ear length, the diameter of the ear and the number of kernel rows. S2‐selection showed no effect or a negative effect on ear quality. The application of a single cycle of selection using either method seemed inadequate for increasing marketable yield. More cycles might be necessary to make significant improvements.Funder:
Software AG – Stiftung
https://doi.org/10.13039/50110001454
Spontaneous outcrossing in tomato depends on cultivar and environment and varies between individual flowers
No full textKnowledge about the degree of spontaneous outcrossing of diverse genotypes is essential for breeding programmes, maintenance breeding, and seed production. For tomato (Lycopersicon esculentum Mill.), very limited scientific evidence for genotypic differences is available and evidence from Europe is scarce. To close this knowledge gap, six cultivars were investigated in three Central European locations as part of the Organic Outdoor Tomato Project. To determine outcrossing rates, the monogenetic “cut‐leaf” trait, which is dominant over the “potato‐leaf” trait, was used as morphological marker. The observed range of outcrossing was 0.0%–5.2%. Outcrossing was significantly influenced by cultivar and environment. The outcrossing rate of individual flowers varied within cultivars ranging from 0% to 37%. The potential of newly opened flowers to accept foreign pollen varied largely with the cultivar. Genotypic differences could partly be linked to flower morphology traits. The potential for recombination between tomato genotypes is generally very low but can be a source for new variation in on‐farm management
Influence of Oleic Acid Content on Yield in Winter Oilseed Rape
No full textWinter oilseed rape (Brassica napus L.) with a high oleic (>75%) and/or low linolenic acid (similar to 2%) content in the seed oil is of interest for nutritional and technical purposes. We analyzed whether a change in seed fatty acid composition has a direct influence on yield. Parental lines with different fatty acid composition were crossed, the segregating F-2 populations were divided, and F-3 bulks with contrasting fatty acid profiles were tested in two experiments. In Experiment 1, we developed four bulks in each of three crosses, which varied in oleic (58 to 82%) and linolenic (2 to 11%) acid content. F-3 bulks were tested for 2 yr at three locations in Germany. In Experiment 2, two F 3 bulks each were developed in 16 segregating F-2 populations with high (74 to 79%) and low (59 to 64%) oleic acid content. F-3 bulks were tested for 1 yr at five locations. The seed linolenic acid content did not significantly affect yield. In both experiments high oleic acid content was negatively associated with yield (with a reduction of 1.7 deciton [dt] ha(-1) and 2.0 dt ha(-1) of high versus low oleic acid bulks in Experiments 1 and 2). High oleic bulks exhibited a significantly increased oil content (+0.6%). Yield was negatively correlated with leaf and seed oleic acid content (r = -0.52 and r = -0.48, respectively). Seeds with high oleic acid content showed a significantly retarded germination. Breeding high oleic varieties could be complicated by the negative correlation between yield and oleic acid content
Breeding of Brassica rapa for Biogas Production: Heterosis and Combining Ability of Biomass Yield
No full textThe use of plant biomass as substrate for biogas production has recently become of major interest in Europe. Winter Brassica rapa produces high early biomass and could be grown as a pre-crop harvested early in the year followed by a second crop such as maize. The objectives of this study were to estimate heterosis and combining ability of 15 European winter B. rapa cultivars for biomass yield at end of flowering. A half-diallel without reciprocals was conducted among cultivars to produce 105 crosses. These crosses and their parents were evaluated in two years at two locations in Northern Germany. Data collected were days to flowering (DTF), fresh biomass yield (FBY), dry matter content (DMC) and dry biomass yield (DBY). The mean DBY was 5.3 t/ha for the parental cultivars and 5.6 t/ha for their crosses. The crosses surpassed on average their parents by 7.6% for FBY and 5.9% for DBY whereas DMC was 1.4% higher in the parents. Maximum mid parent heterosis was 21.0% for FBY and 30.4% for DBY. Analysis of variance showed that genetic variance was mainly due to specific combining ability (SCA). The correlation between parental performance and general combining ability (GCA) was 0.42 for FBY and 0.53 for DBY. In conclusion, the amount of heterosis in crosses between European winter B. rapa cultivars is not very high on average, but can be up to 30% in the best crosses. Selection of parental combinations with high specific combining ability to produce synthetic cultivars can rapidly improve biomass yield.KWS Saat AG, Einbeck; FNR (Agency for Renewable Resources) German
Genetic variation in leaf and stem glucosinolates in resynthesized lines of winter rapeseed (Brassica napus L.)
Full text linkGlucosinolates are secondary components characteristic for the Brassicaceae with complex biological functions. Glucosinolates in the seeds are anti-nutritive when feeding animals and their inheritance have been extensively investigated. Much less is known about the genetics of glucosinolates in leaves and stems, which may attract some insects, while repelling others. They may also inhibit bacterial processes of importance when using green biomass for the production of biogas. The objective of this study was to analyse the genetic variation of total and individual glucosinolates in the green material of rapeseed. For this 28 resynthesized winter rapeseed lines were tested at two locations. There was a large variation in leaf glucosinolate content between 0.10 and 4.75 mu mol/g dry matter. The predominant leaf glucosinolates are the alkenyle glucosinolates progoitrin, gluconapin and glucobrassicanapin. The line R53 is exceptional, while combining a relative high content of the indole glucosinolate glucobrassicin with low alkenyle glucosinolates in the leaves. The total glucosinolate concentration in the stems and leaves is not correlated with the seed glucosinolate concentrations. Heritabilities are above hA(2)A = 0.60 for progoitrin, hA(2)A = 0.65 for gluconapin, hA(2)A = 0.30 for glucobrassicanapin and hA(2)A = 0.52 for total glucosinolate content in the leaves. In conclusion, resynthesized rapeseed is an important genetic resource to modify the leaf glucosinolate content and composition of rapeseed.Deutsche Bundesstiftung Umwelt (DBU
Selection for Phytophthora field resistance in the F2 generation of organic outdoor tomatoes
No full textTomatoes are the most important vegetable, globally as well as in Germany. Outdoor tomato production is seriously impaired due to increasing infections with evolving late blight (Phytophthora infestans) populations. Within organic agriculture, research is being conducted to develop regionally adapted and open pollinated cultivars of outdoor tomatoes with late blight field resistance. In the present experiment, three crosses, including wild, cocktail, and beefsteak tomatoes, were selected for field resistance against late blight in F2 at one location per cross. The comparison of positive and negative selection in F3 revealed the selection of single F2 plants to be efficient in all three crosses. F2 selection has proved to be a robust and efficient tool for breeding programs. The correlated response to selection in other traits, including yield, fruit weight, days to maturity, harvest period, and plant height, depended on the cross. It was evident that selection for desired traits combined with field resistance against late blight is promising, even in wide crosses. The most undesired attribute of wild tomatoes is the formation of shoots on leaves and in inflorescences. No correlation was observed between field resistance and shoot formation, allowing the selection of genotypes with improved field resistance and yield, but without morphological disadvantages
Crop Adaptation in On‐Farm Management by Natural and Conscious Selection: A Case Study with Lentil
No full textOn-farm management of landraces or older cultivars of crop plants is often recommended to combine conservation and use of genetic resources, but experimental studies on on- farm management are hard to fi nd, particu- larly in industrialized countries. To investigate whether on-farm management results in regional adaptation and enhances crop biodi- versity, an experiment with lentils (Lens culi- naris Medik.) was designed. Lentil production has almost ceased to exist in central Europe, but lentils may still be found in gene banks and have remained a popular food. Three landraces were evaluated on three farms in Germany; at each farm, three populations evolved, based on three selection methods: (i) natural selection, (ii) visual mass selection, and (iii) selection for yield of single plant progenies. These selection methods were applied for two to four years. The nine populations developed for each landrace (three methods × three locations) were grown in a comparative trial on two of the farms. In most cases, populations selected at a specifi c location were at this location superior in yield to populations selected at other locations, indi- cating that on-farm management can result in site-specifi c adaptation. Signifi cant changes in morphological and phenological traits occurred. For one landrace, natural selection increased seed weight. The response to different selec- tion methods largely depended on landrace and selection site, and no method was generally superior. In conclusion, on-farm management is a useful approach to maintain, use, and develop plant genetic resources. Natural selection as the most cost-effi cient method is recommended
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