Dynamic management of genetic resources: a 13-year experiment on wheat.

Goldringer, Isabelle; Enjalbert, Jean-Nicolas; David, Juan; Paillard, Sophie; Pham, Jean‐Louis; Brabant, Philippe; Cooper, H. D.; Spillane, Charles; Hodgkin, T.

doi:10.1079/9780851994116.0245

Cited by 34 publications

(34 citation statements)

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“…The ratio N e /N e d = 0.04 is low, but not far from the 1/10 ratio commonly found in other studies (Frankham 1995;Luikart et al 2010). Note that this value is similar to that estimated by Goldringer et al (2001) for selfing populations in dynamic management (N e /N e d = 0.03, with N e ranging from 40 to 150). Higher N e for an outcrossing population is expected, with a theoretical twofold difference due to the uncorrelated segregation of the two alleles present in each open-pollinated individual, as well as to the lower transmission of reproductive success to a recombinant progeny (Austerlitz and Heyer 1998).…”

Section: Discussionsupporting

confidence: 66%

Efficiently Tracking Selection in a Multiparental Population: The Case of Earliness in Wheat

Thepot

Restoux

Goldringer³

et al. 2014

Genetics

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Multiparental populations are innovative tools for fine mapping large numbers of loci. Here we explored the application of a wheat Multiparent Advanced Generation Inter-Cross (MAGIC) population for QTL mapping. This population was created by 12 generations of free recombination among 60 founder lines, following modification of the mating system from strict selfing to strict outcrossing using the ms1b nuclear male sterility gene. Available parents and a subset of 380 SSD lines of the resulting MAGIC population were phenotyped for earliness and genotyped with the 9K i-Select SNP array and additional markers in candidate genes controlling heading date. We demonstrated that 12 generations of strict outcrossing rapidly and drastically reduced linkage disequilibrium to very low levels even at short map distances and also greatly reduced the population structure exhibited among the parents. We developed a Bayesian method, based on allelic frequency, to estimate the contribution of each parent in the evolved population. To detect loci under selection and estimate selective pressure, we also developed a new method comparing shifts in allelic frequency between the initial and the evolved populations due to both selection and genetic drift with expectations under drift only. This evolutionary approach allowed us to identify 26 genomic areas under selection. Using association tests between flowering time and polymorphisms, 6 of these genomic areas appeared to carry flowering time QTL, 1 of which corresponds to Ppd-D1, a major gene involved in the photoperiod sensitivity. Frequency shifts at 4 of 6 areas were consistent with earlier flowering of the evolved population relative to the initial population. The use of this new outcrossing wheat population, mixing numerous initial parental lines through multiple generations of panmixia, is discussed in terms of power to detect genes under selection and association mapping. Furthermore we provide new statistical methods for use in future analyses of multiparental populations.KEYWORDS QTL detection; parental contribution; recombinant population; selection detection; experimental evolution; multiparental populations; Multiparent Advanced Generation Inter-Cross (MAGIC); MPPA LTHOUGH the recent development of genome sequencing in crop species has strongly increased capacity for gene discovery, the accurate mapping of genes controlling the genetic variation of complex traits (QTL) remains a key objective. The principal mapping methods rely on the detection of statistical association between polymorphisms at molecular markers and quantitative variation of phenotypic traits and were historically developed for progenies of biparental crosses with parents chosen for their extreme phenotypes at a trait of interest. These populations are powerful resources for QTL detection, but have low precision as few effective meioses (and thus subsequent recombinations) occur during their development. As a result, large parental haplotype blocks are preserved in the segregating population. In a...

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Section: Discussionsupporting

confidence: 66%

Efficiently Tracking Selection in a Multiparental Population: The Case of Earliness in Wheat

Thepot

Restoux

Goldringer³

et al. 2014

Genetics

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“…It ensures also that the populations are able to adapt and evolve to changing selective pressures in different environments and provides enough genetic diversity so that advantageous genetic combinations can arise, including novel and beneficial alleles through mutation and migration (Paillard et al, 2000;Goldringer et al, 2001Goldringer et al, , 2006Porcher et al, 2004;Phillips and Wolfe, 2005;Stange et al, 2006;Döring et al, 2011). However, the need to improve baking quality characteristics and protein content in genetically diverse populations is essential in order to promote the wider use of CC populations in agriculture.…”

Section: Introductionmentioning

confidence: 99%

“…This breeding strategy fulfils a number of goals that in light of the negative consequences of agriculture based on genetically uniform crops should be promoted and encouraged. Dynamic management of genetic resources, achieved through the cultivation of genetically diverse populations such as CCPs, subjected to different environments and selective pressures, provides an excellent complementary tool with which to conserve the genetic diversity of agricultural crops (Paillard et al, 2000;Goldringer et al, 2001Goldringer et al, , 2006Porcher et al, 2004;Phillips and Wolfe, 2005;Döring et al, 2011). In addition, CCPs are widely used as a resource for selection (Clark et al, 2006;Jackson, 2011;Enjalbert et al, 2011;Goldringer et al, 2001Goldringer et al, , 2006Döring et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Evolutionary changes of weed competitive traits in winter wheat composite cross populations in organic and conventional farming systems

Bertholdsson

Weedon

Brumlop

et al. 2016

European Journal of Agronomy

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a b s t r a c tSeedling root and shoot growth in hydroponics and allelopathic activity using a bioassay have been studied in very diverse populations of winter wheat grown under either organic or conventional conditions for a number of generations and subjected only to natural selection. The study was conducted on seeds from generation 6 (F 6 ) and 11 (F 11 ) from three composite cross populations (CCPs) produced by the Organic Research Centre in the UK. Since the F 5 the populations were maintained under organic and conventional conditions in Germany. Two parallel populations were created from each CC, resulting in a total of six organic and six conventional CCPs. The sets of parallel populations showed similar evolutionary trends indicating that the observed changes are related to differences in management rather than chance. Seedling root length and seedling root and shoot weight in the F 11 of the organically-managed CCPs were significantly greater than in the organic F 6 CCPs. In the conventionally-managed CCPs no such differences were observed. Both organic and conventional CCPs produced for quality showed higher early root and shoot growth than those produced for yield pointing to genetic differences among population types and highlighting the importance of early vigour for NUE. There were no significant differences in the allelopathic activity of the populations and between generations. The Shannon-Weaver diversity indices were similar for the studied traits in organic and conventional CCPs and hence no major changes in diversity had occurred between F 6 to F 11 . As changes in plant height were small and weed pressure in the fields low it is concluded that the observed differences are more related to NUE, rather than intra-specific competition for light or the direct effect of increased weed pressure in the organic system.

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“…Dynamic management (DM) is an evolutionary approach for the conservation of the genetic resources of crop species (Henry et al, 1991;Goldringer et al, 2001). DM aims at maintaining the genetic diversity of crop species by growing successive generations of genetically diverse populations in several contrasted environments, without intentional human selection.…”

Section: Introductionmentioning

confidence: 99%

Inbreeding depression and low between-population heterosis in recently diverged experimental populations of a selfing species

et al. 2010

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In fragmented populations, genetic drift and selection reduce genetic diversity, which in turn results in a loss of fitness or in a loss of evolvability. Genetic rescue, that is, controlled input of diversity from distant populations, may restore evolutionary potential, whereas outbreeding depression might counteract the positive effect of this strategy. We carried out self-pollination and crosses within and between populations in an experimental subdivided population of a selfing species, Triticum aestivum L., to estimate the magnitude of these two phenomena. Surprisingly, for a self-fertilizing species, we found significant inbreeding depression within each population for four of the six traits studied, indicating that mildly deleterious mutations were still segregating in these populations. The progeny of within-and betweenpopulation crosses was very similar, indicating low betweenpopulation heterosis and little outbreeding depression. We conclude that relatively large population effective sizes prevented fixation of a high genetic load and that local adaptation was limited in these recently diverged populations. The kinship coefficient estimated between the parents using 20 neutral markers was a poor predictor of the progeny phenotypic values, indicating that there was a weak link between neutral diversity and genes controlling fitnessrelated traits. These results show that when assessing the viability of natural populations and the need for genetic rescue, the use of neutral markers should be complemented with information about the presence of local adaptation in the subdivided population.

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Dynamic management of genetic resources: a 13-year experiment on wheat.

Abstract: This chapter reviews the available results concerning the 13-year wheat dynamic management (DM) experiment and discusses the possible use of the DM approach as a conservation strategy as well as a pre-breeding or base-broadening method.

Cited by 34 publications

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Efficiently Tracking Selection in a Multiparental Population: The Case of Earliness in Wheat

Efficiently Tracking Selection in a Multiparental Population: The Case of Earliness in Wheat

Evolutionary changes of weed competitive traits in winter wheat composite cross populations in organic and conventional farming systems

Inbreeding depression and low between-population heterosis in recently diverged experimental populations of a selfing species

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