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M. L. Warburton J. M. Ribaut J. Franco J. Crossa P. Dubreuil F. J. Betrán 《Euphytica》2005,142(1-2):97-106
Characterization of genetic diversity among maize inbred lines can facilitate organization of germplasm and improve efficiency of breeding programs. A set of 218 phenotypically diverse inbred maize lines developed at CIMMYT for hybrid production was characterized using 32 RFLP markers to: (1) analyze the genetic diversity present; (2) define potential heterotic groups based on clusters formed with marker data; and (3) identify the most representative testers for each potential heterotic group. Lines were clustered using five different genetic distance measurements to find consensus non-hierarchical clusters. Dendrograms were produced to study hierarchical classification within smaller groups of lines. A very high average allelic diversity was seen in this germplasm. Lines did not cluster based on phenotype, environmental adaptation, grain color or type, maturity, or heterotic response (as determined based on hybrid performance with testers), but lines related by pedigree usually did cluster together. Previously defined testers from opposite heterotic groups were not genetically differentiated, and did not represent well their heterotic group. Discrete clusters were difficult to find; thus, potential heterotic groups will be difficult to suggest using RFLP markers alone. However, suggestions on how to use molecular markers and cross performance information to refine heterotic groups and select representative testers are presented. 相似文献
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Dan?MakumbiEmail author Javier?F.?Betrán Marianne?B?nziger Jean-Marcel?Ribaut 《Euphytica》2011,180(2):143-162
Drought and low soil fertility are considered the most important abiotic stresses limiting maize production in sub-Saharan
Africa. Knowledge of the combining ability and diversity of inbred lines with tolerance to the two stresses and for those
used as testers would be beneficial in setting breeding strategies for stress and nonstress environments. We used 15 tropical
maize inbred lines to (i) evaluate the combining ability for grain yield (GY), (ii) assess the genetic diversity of this set
of inbred lines using RFLP, SSR, and AFLP markers, (iii) estimate heterosis and assess the relationship between F1 hybrid performance, genetic diversity and heterosis, and (iv) assess genotype × environment interaction of inbred lines and
their hybrids. The F1 diallel hybrids and parental inbreds were evaluated under drought stress, low N stress, and well-watered conditions at six
locations in three countries. General combining ability (GCA) effects were highly significant (P < 0.01) for GY across stresses and well-watered environments. Inbred lines CML258, CML339, CML341, and CML343 had the best
GCA effects for GY across environments. Additive genetic effects were more important for GY under drought stress and well-watered
conditions but not under low N stress, suggesting different gene action in control of GY. Clustering based on genetic distance
(GD) calculated using combined marker data grouped lines according to pedigree. Positive correlation was found between midparent
heterosis (MPH) and specific combining ability (SCA), GD and GY. Hybrid breeding program targeting stress environments would
benefit from the accumulation of favorable alleles for drought tolerance in both parental lines. 相似文献
3.
Recent advances in genomics bioinformatics now offer real opportunities for dissecting complex traits into their component sub-traits which will simplify the process of developing the tools necessary to manipulate the underlying genes 《分子植物育种》2007,5(2):199-200
Recent advances in genomics and bioinformatics now offer real opportunities for dissecting complex Waits into their component sub-traits, which will simplify the process of developing the tools necessary to manipulate the underlying genes （Varshney et al., 2005）. The value of molecular markers as a complement to phenotyping under several breeding scenarios is largely unquestioned, as demonstrated by the increasing number of successful studies published （Varshney et al., 2006）. However most experiments have targeted crop improvement for disease resistance, morphological waits or quality waits （Franca et al., 2005） and there is still some way to go before markers can be used routinely and ubiquitously to breed for complex waits, such as tolerance to abiotic stress （Ribaut and Ragot, 2007）. The combination of genetic mapping and association studies has considerable potential to generate a catalogue of genetic variation, and thereby present novel opportunities for selection based on genome-wide scans （Biswas and Akey, 2006）. Nevertheless, it remains to be seen whether the outcome of gene interactions, particularly where significant gene networks are involved, 相似文献
4.
Evaluation of aluminium tolerance in a spring rye collection by hydroponic screening 总被引：2，自引：0，他引：2
A. R. Hede B. Skovmand J.-M. Ribaut D. González-de -León O. Stølen 《Plant Breeding》2002,121(3):241-248
Aluminium (A1) tolerance of 63 rye accessions from a world spring rye collection was evaluated using the haematoxylin method and the root growth method. The haematoxylin method is based on the ability of A1‐tolerant seedlings to continue root growth following a short pulse treatment with a high Al concentration, while the root growth method uses the root growth and root tolerance index to judge A1 tolerance. Significantly higher levels of A1 tolerance were found in rye than in the A1‐tolerant bread wheat cultivar ‘Maringa’. Under the assumption that the ability of roots to grow under A1 stress is a combination of root vigour (long roots) and A1 tolerance, a hypothesis allowing for the differentiation of five genotype classes was suggested. This study demonstrated that the haematoxylin method and the root growth parameter identify genotypes with long root growth under A1 stress, but failed to detect A1 tolerance in genotypes with poor root vigour. These genotypes can only be identified using the root tolerance index parameter. However, the haematoxylin method is highly suitable for screening large segregating populations derived from improved germplasm that has been preselected for agronomically preferable traits, including plant vigour. 相似文献
5.
Marcos Malosetti Jean Marcel Ribaut Mateo Vargas José Crossa Fred A. van Eeuwijk 《Euphytica》2008,161(1-2):241-257
Despite QTL mapping being a routine procedure in plant breeding, approaches that fully exploit data from multi-trait multi-environment
(MTME) trials are limited. Mixed models have been proposed both for multi-trait QTL analysis and multi-environment QTL analysis,
but these approaches break down when the number of traits and environments increases. We present models for an efficient QTL
analysis of MTME data with mixed models by reducing the dimensionality of the genetic variance–covariance matrix by structuring
this matrix using direct products of relatively simple matrices representing variation in the trait and environmental dimension.
In the context of MTME data, we address how to model QTL by environment interactions and the genetic basis of heterogeneity
of variance and correlations between traits and environments. We illustrate our approach with an example including five traits
across eight stress trials in CIMMYT maize. We detected 36 QTLs affecting yield, anthesis-silking interval, male flowering,
ear number, and plant height in maize. Our approach does not require specialised software as it can be implemented in any
statistical package with mixed model facilities. 相似文献
6.
Drought stress and tropical maize: QTLs for leaf greenness, plant senescence, and root capacitance 总被引：2，自引：0，他引：2
Rainer Messmer Yvan Fracheboud Marianne BänzigerPeter Stamp Jean-Marcel Ribaut 《Field Crops Research》2011,124(1):93-103
Genetically improved crops with higher water productivity help maintaining and increasing agricultural production in drought-prone areas. Their development involves, as in the case of maize, selection for high grain yield and improved secondary traits. With the objective of better understanding the role and regulation of the morphology of drought adaptation, a recombinant inbred line (RIL) population of tropical maize (Zea mays L.) was evaluated in six field experiments under intermediate (IS) and severe (SS) drought stress at flowering and under well-watered (WW) conditions in Mexico. The analyses per water regime revealed 32 quantitative trait loci (QTLs) for the five measurements of relative content of leaf chlorophyll (CL), 25 for the five visual ratings of plant senescence (SEN), and 11 for the three measurements of electric root capacitance (RCT). Impressive clusters of QTLs were observed on chromosomes 2 (bins 2.03-05), 4 (bin 4.09), and 10 (bins 10.04-05), suggesting that a small number of genes control chlorophyll metabolism and plant senescence. The high CL and low SEN of the drought resistant parent are aspects of its high water productivity resulting from improved constitutive traits. Co-locations of QTLs for CL, SEN and RCT with QTLs for plant height (PHT), the anthesis-silking interval (ASI), and grain yield (GY) were observed in bins 1.06-07, 8.06, and 4.09 but not for the large QTL clusters on chromosomes 2 and 10, suggesting independent genetic control of reproductive traits. Still, the phenotypic data showed that high CL and low SEN were favorable for grain yield production under drought, while delayed SEN was associated with higher grain yield under WW conditions. CL and SEN are suitable to complement selection for drought tolerance in order to sustain future breeding progress. 相似文献
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