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71.
Jonathan Mühleisen Hans-Peter Piepho Hans Peter Maurer Carl Friedrich Horst Longin Jochen Christoph Reif 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2014,127(2):309-316
Key message
We present experimental data for wheat, barley, and triticale suggesting that hybrids manifest on average higher yield stability than inbred lines.Abstract
Yield stability is assumed to be higher for hybrids than for inbred lines, but experimental data proving this hypothesis is scarce for autogamous cereals. We used multi-location grain yield trials and compared the yield stability of hybrids versus lines for wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and triticale (×Triticosecale Wittmack). Our study comprised three phenotypic data sets of 1,749 wheat, 96 barley, and 130 triticale genotypes, which were evaluated for grain yield in up to five contrasting locations. Yield stability of the group of hybrids was compared with that of the group of inbred lines estimating the stability variance. For all three crops we observed a significantly (P < 0.05) higher yield stability of hybrids compared to lines. The enhanced yield stability of hybrids as compared to lines represents a major step forward, facilitating coping with the increasing abiotic stress expected from the predicted climate change. 相似文献72.
M Gowda Y Zhao T Würschum C FH Longin T Miedaner E Ebmeyer R Schachschneider E Kazman J Schacht J-P Martinant M F Mette J C Reif 《Heredity》2014,112(5):552-561
The accuracy of genomic selection depends on the relatedness between the members of the
set in which marker effects are estimated based on evaluation data and the types for which
performance is predicted. Here, we investigate the impact of relatedness on the
performance of marker-assisted selection for fungal disease resistance in hybrid wheat. A
large and diverse mapping population of 1739 elite European winter wheat inbred lines and
hybrids was evaluated for powdery mildew, leaf rust and stripe rust resistance in
multi-location field trials and fingerprinted with 9 k and 90 k SNP arrays.
Comparison of the accuracies of prediction achieved with data sets from the two marker
arrays revealed a crucial role for a sufficiently high marker density in genome-wide
association mapping. Cross-validation studies using test sets with varying degrees of
relationship to the corresponding estimation sets revealed that close relatedness leads to
a substantial increase in the proportion of total genotypic variance explained by the
identified QTL and consequently to an overoptimistic judgment of the precision of
marker-assisted selection. 相似文献
73.
Hybrid wheat: quantitative genetic parameters and consequences for the design of breeding programs 总被引:2,自引:0,他引:2
Carl Friedrich Horst Longin Manje Gowda Jonathan Mühleisen Erhard Ebmeyer Ebrahim Kazman Ralf Schachschneider Johannes Schacht Martin Kirchhoff Yusheng Zhao Jochen Christoph Reif 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2013,126(11):2791-2801
Key message
Commercial heterosis for grain yield is present in hybrid wheat but long-term competiveness of hybrid versus line breeding depends on the development of heterotic groups to improve hybrid prediction.Abstract
Detailed knowledge of the amount of heterosis and quantitative genetic parameters are of paramount importance to assess the potential of hybrid breeding. Our objectives were to (1) examine the extent of midparent, better-parent and commercial heterosis in a vast population of 1,604 wheat (Triticum aestivum L.) hybrids and their parental elite inbred lines and (2) discuss the consequences of relevant quantitative parameters for the design of hybrid wheat breeding programs. Fifteen male lines were crossed in a factorial mating design with 120 female lines, resulting in 1,604 of the 1,800 potential single-cross hybrid combinations. The hybrids, their parents, and ten commercial wheat varieties were evaluated in multi-location field experiments for grain yield, plant height, heading time and susceptibility to frost, lodging, septoria tritici blotch, yellow rust, leaf rust, and powdery mildew at up to five locations. We observed that hybrids were superior to the mean of their parents for grain yield (10.7 %) and susceptibility to frost (?7.2 %), leaf rust (?8.4 %) and septoria tritici blotch (?9.3 %). Moreover, 69 hybrids significantly (P < 0.05) outyielded the best commercial inbred line variety underlining the potential of hybrid wheat breeding. The estimated quantitative genetic parameters suggest that the establishment of reciprocal recurrent selection programs is pivotal for a successful long-term hybrid wheat breeding. 相似文献74.
75.
76.
Population structure, genetic diversity and linkage disequilibrium in elite winter wheat assessed with SNP and SSR markers 总被引:3,自引:0,他引:3
Tobias Würschum Simon M. Langer C. Friedrich H. Longin Viktor Korzun Eduard Akhunov Erhard Ebmeyer Ralf Schachschneider Johannes Schacht Ebrahim Kazman Jochen C. Reif 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2013,126(6):1477-1486
Modern genomics approaches rely on the availability of high-throughput and high-density genotyping platforms. A major breakthrough in wheat genotyping was the development of an SNP array. In this study, we used a diverse panel of 172 elite European winter wheat lines to evaluate the utility of the SNP array for genomic analyses in wheat germplasm derived from breeding programs. We investigated population structure and genetic relatedness and found that the results obtained with SNP and SSR markers differ. This suggests that additional research is required to determine the optimum approach for the investigation of population structure and kinship. Our analysis of linkage disequilibrium (LD) showed that LD decays within approximately 5–10 cM. Moreover, we found that LD is variable along chromosomes. Our results suggest that the number of SNPs needs to be increased further to obtain a higher coverage of the chromosomes. Taken together, SNPs can be a valuable tool for genomics approaches and for a knowledge-based improvement of wheat. 相似文献
77.
Bacillus subtilis F0F1 ATPase: DNA sequence of the atp operon and characterization of atp mutants. 总被引:3,自引:4,他引:3 下载免费PDF全文
M Santana M S Ionescu A Vertes R Longin F Kunst A Danchin P Glaser 《Journal of bacteriology》1994,176(22):6802-6811
We cloned and sequenced an operon of nine genes coding for the subunits of the Bacillus subtilis F0F1 ATP synthase. The arrangement of these genes in the operon is identical to that of the atp operon from Escherichia coli and from three other Bacillus species. The deduced amino acid sequences of the nine subunits are very similar to their counterparts from other organisms. We constructed two B. subtilis strains from which different parts of the atp operon were deleted. These B. subtilis atp mutants were unable to grow with succinate as the sole carbon and energy source. ATP was synthesized in these strains only by substrate-level phosphorylation. The two mutants had a decreased growth yield (43 and 56% of the wild-type level) and a decreased growth rate (61 and 66% of the wild-type level), correlating with a twofold decrease of the intracellular ATP/ADP ratio. In the absence of oxidative phosphorylation, B. subtilis increased ATP synthesis through substrate-level phosphorylation, as shown by the twofold increase of by-product formation (mainly acetate). The increased turnover of glycolysis in the mutant strain presumably led to increased synthesis of NADH, which would account for the observed stimulation of the respiration rate associated with an increase in the expression of genes coding for respiratory enzymes. It therefore appears that B. subtilis and E. coli respond in similar ways to the absence of oxidative phosphorylation. 相似文献
78.
Longin CF Utz HF Reif JC Wegenast T Schipprack W Melchinger AE 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,115(4):519-527
Early testing prior to doubled haploid (DH) production is a promising approach in hybrid maize breeding. We (1) determined
the optimum allocation of the number of S1 families, DH lines, and test locations for two different breeding schemes, (2) compared the maximum selection gain achievable
under both breeding schemes, and (3) investigated limitations in the current method of DH production. Selection gain was calculated
by numerical integration in two-stage breeding schemes with evaluation of testcross progenies of (1) DH lines in both stages
(DHTC), or (2) S1 families in the first and DH lines within S1 families in the second stage (S1TC-DHTC). Different assumptions were made regarding the budget, variance components, and time of DH production within S1 families. Maximum selection gain in S1TC-DHTC was about 10% larger than in DHTC, indicating the large potential of early testing prior to DH production. The optimum
allocation of test resources in S1TC-DHTC involved similar numbers of test locations and test candidates in both stages resulting in a large optimum number
of S1 families in the first stage and DH lines within the best two S1 families in the second stage. The longer cycle length of S1TC-DHTC can be compensated by haploid induction of individual S1 plants instead of S1 families. However, this reduces selection gain largely due to the current limitations in the DH technique. Substantial increases
in haploid induction and chromosome doubling rates as well as reduction in costs of DH production would allow early testing
of S1 lines and subsequent production and testing of DH lines in a breeding scheme that combines high selection gain with a short
cycle length.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
79.
In this study we provide experimental evidence of transmission of growth anomalies (GAs) between corals. Twenty-four aquaria (16 experimental, 8 containing only apparently healthy corals) were set-up on Negros Island, Philippines, to test for direct-contact and waterborne transmission of GAs. Within seven weeks, two of 16 apparently healthy colonies placed in direct contact with colonies having GAs developed multiple GA lesions whose size and number increased over time. One of 16 apparently healthy colonies in experimental aquaria not touching any diseased colony also developed a GA, exhibiting a single lesion that did not increase in size. Apparently healthy colonies (n=24) in aquaria without a diseased colony remained unchanged. 相似文献
80.