Search

When plants establish outside their native range, their ability to adapt to the new environment is influenced by both demography and dispersal. However, the relative importance of these two factors is poorly understood. To quantify the influence of demography and dispersal on patterns of genetic diversity underlying adaptation, we used data from a globally distributed demographic research network comprising 35 native and 18 nonnative populations of Plantago lanceolata Species-specific simulation experiments showed that dispersal would dilute demographic influences on genetic diversity at local scales. Populations in the native European range had strong spatial genetic structure associated with geographic distance and precipitation seasonality. In contrast, nonnative populations had weaker spatial genetic structure that was not associated with environmental gradients but with higher within-population genetic diversity. Our findings show that dispersal caused by repeated, long-distance, human-mediated introductions has allowed invasive plant populations to overcome environmental constraints on genetic diversity, even without strong demographic changes. The impact of invasive plants may, therefore, increase with repeated introductions, highlighting the need to constrain future introductions of species even if they already exist in an area.

Figure S1. Predictive ability and bias for crown rust using various algorithms for genomic prediction. (PDF 101 kb)

Figure S2. Among-and-within-full-sib-family selection that incorporates an inexpensive genotyping assay to implement within-family selection using a high selection intensity. (PDF 227 kb)

The conservation of crop genetic resources requires understanding the different variables-cultural, social, and economic-that impinge on crop diversity. In small-scale farming systems, seed exchanges represent a key mechanism in the dynamics of crop genetic diversity, and analyzing the rules that structure social networks of seed exchange between farmer communities can help decipher patterns of crop genetic diversity. Using a combination of ethnobotanical and molecular genetic approaches, we investigated the relationships between regional patterns of manioc genetic diversity in Gabon and local networks of seed exchange. Spatially explicit Bayesian clustering methods showed that geographical discontinuities of manioc genetic diversity mirror major ethnolinguistic boundaries, with a southern matrilineal domain characterized by high levels of varietal diversity and a northern patrilineal domain characterized by low varietal diversity. Borrowing concepts from anthropology-kinship, bridewealth, and filiation-we analyzed the relationships between marriage exchanges and seed exchange networks in patrilineal and matrilineal societies. We demonstrate that, by defining marriage prohibitions, kinship systems structure social networks of exchange between farmer communities and influence the movement of seeds in metapopulations, shaping crop diversity at local and regional levels. The conservation of crop genetic resources requires understanding the different variables-cultural, social, and economic-that impinge on crop diversity. In small-scale farming systems, seed exchanges represent a key mechanism in the dynamics of crop genetic diversity, and analyzing the rules that structure social networks of seed exchange between farmer communities can help decipher patterns of crop genetic diversity. Using a combination of ethnobotanical and molecular genetic approaches, we investigated the relationships between regional patterns of manioc genetic diversity in Gabon and local networks of seed exchange. Spatially explicit Bayesian clustering methods showed that geographical discontinuities of manioc genetic diversity mirror major ethnolinguistic boundaries, with a southern matrilineal domain characterized by high levels of varietal diversity and a northern patrilineal domain characterized by low varietal diversity. Borrowing concepts from anthropology-kinship, bridewealth, and filiation-we analyzed the relationships between marriage exchanges and seed exchange networks in patrilineal and matrilineal societies. We demonstrate that, by defining marriage prohibitions, kinship systems structure social networks of exchange between farmer communities and influence the movement of seeds in metapopulations, shaping crop diversity at local and regional levels. Teagasc IRCSET

Key to Thai species of Dimeria 1. Racemes solitary................................................................................................................................................................................2. - Racemes more than one.....................................................................................................................................................................4. 2. Spikelets 4.5–5 mm long. Rhachis 0.8–1.2 mm wide....................................................................................... D. kurumthotticalana - Spikelets 3–4 mm long. Rhachis 0.4–0.7 mm wide..........................................................................................................................3. 3. Upper glumes wingless........................................................................................................................................................... D. kurzii - Upper glumes winged......................................................................................................................................................... D. sinensis 4. Racemes with filiform rhachis............................................................................................................................................ D. velutina - Racemes with flattened or triangular rhachis....................................................................................................................................5. 5. Spikelets 1–3(–4.5) mm long; upper glumes wingless. Rhachis 0.2–0.4 mm wide.................................................... D. ornithopoda - Spikelets 4–6 mm long; upper glumes winged. Rhachis 0.6–1.2 mm wide......................................................................................6. 6. Upper glumes broadly winged. Wings rugose........................................................................................................................ D. kerrii - Upper glumes narrowly winged. Wings not rugose..........................................................................................................................7. 7. Rhachis 0.7–0.8 mm wide, rhachis internodes 1.5–2(–2.5) mm long. Upper glumes acute, narrowly winged all along the keel.............................................................................................................................................................................................. D. fuscescens - Rhachis 0.8 − 1.2 mm wide, rhachis internodes 0.8–1.5 mm long. Upper glumes acuminate to long acuminate and slightly recurved, narrowly winged in the upper one third of glume to the apex........................................................................... D. kurumthotticalana, Published as part of Teerawatananon, Atchara, Boontia, Veeraya, Chantarasuwan, Bhanumas, Hodkinson, Trevor R. & Sungkaew, Sarawood, 2014, A taxonomic revision of the genus Dimeria (Poaceae: Panicoideae) in Thailand, pp. 137-147 in Phytotaxa 186 (3) on page 138, DOI: 10.11646/phytotaxa.186.3.2, http://zenodo.org/record/5147015