Fescue species breeding evaluation and interspecific hybridization

Santr. angl., rusBibliogr.: p. 79 (3 pavad.)Vytauto Didžiojo universitetasŽemės ūkio akademij

Escape to Ferality: The Endoferal Origin of Weedy Rice from Crop Rice through De-Domestication.

Domestication is the hallmark of evolution and civilization and harnesses biodiversity through selection for specific traits. In regions where domesticated lines are grown near wild relatives, congeneric sources of aggressive weedy genotypes cause major economic losses. Thus, the origins of weedy genotypes where no congeneric species occur raise questions regarding management effectiveness and evolutionary mechanisms responsible for weedy population success. Since eradication in the 1970s, California growers avoided weedy rice through continuous flood culture and zero-tolerance guidelines, preventing the import, presence, and movement of weedy seeds. In 2003, after decades of no reported presence in California, a weedy rice population was confirmed in dry-seeded fields. Our objectives were to identify the origins and establishment of this population and pinpoint possible phenotypes involved. We show that California weedy rice is derived from a different genetic source among a broad range of AA genome Oryzas and is most recently diverged from O. sativa temperate japonica cultivated in California. In contrast, other weedy rice ecotypes in North America (Southern US) originate from weedy genotypes from China near wild Oryza, and are derived through existing crop-wild relative crosses. Analyses of morphological data show that California weedy rice subgroups have phenotypes like medium-grain or gourmet cultivars, but have colored pericarp, seed shattering, and awns like wild relatives, suggesting that reversion to non-domestic or wild-like traits can occur following domestication, despite apparent fixation of domestication alleles. Additionally, these results indicate that preventive methods focused on incoming weed sources through contamination may miss burgeoning weedy genotypes that rapidly adapt, establish, and proliferate. Investigating the common and unique evolutionary mechanisms underlying global weed origins and subsequent interactions with crop relatives sheds light on how weeds evolve and addresses broader questions regarding the stability of selection during domestication and crop improvement

Contrasting patterns of variation in weedy traits and unique crop features in divergent populations of US weedy rice (Oryza sativa sp.) in Arkansas and California.

Weed evolution from crops involves changes in key traits, but it is unclear how genetic and phenotypic variation contribute to weed diversification and productivity. Weedy rice is a conspecific weed of rice (Oryza sativa) worldwide. We used principal component analysis and hierarchical clustering to understand how morphologically and evolutionarily distinct US weedy rice populations persist in rice fields in different locations under contrasting management regimes. Further, we used a representative subset of 15 sequence-tagged site fragments of expressed genes from global Oryza to assess genome-wide sequence variation among populations.Crop hull color and crop-overlapping maturity dates plus awns, seed (panicle) shattering (> 50%), pigmented pericarp and stature variation (30.2% of total phenotypic variance) characterize genetically less diverse California weedy rice. By contrast, wild-like hull color, seed shattering (> 50%) and stature differences (55.8% of total phenotypic variance) typify genetically diverse weedy rice ecotypes in Arkansas.Recent de-domestication of weedy species - such as in California weedy rice - can involve trait combinations indistinguishable from the crop. This underscores the need for strict seed certification with genetic monitoring and proactive field inspection to prevent proliferation of weedy plant types. In established populations, tillage practice may affect weed diversity and persistence over time. © 2017 Society of Chemical Industry

Escape to Ferality: The Endoferal Origin of Weedy Rice from Crop Rice through De-Domestication

<div><p>Domestication is the hallmark of evolution and civilization and harnesses biodiversity through selection for specific traits. In regions where domesticated lines are grown near wild relatives, congeneric sources of aggressive weedy genotypes cause major economic losses. Thus, the origins of weedy genotypes where no congeneric species occur raise questions regarding management effectiveness and evolutionary mechanisms responsible for weedy population success. Since eradication in the 1970s, California growers avoided weedy rice through continuous flood culture and zero-tolerance guidelines, preventing the import, presence, and movement of weedy seeds. In 2003, after decades of no reported presence in California, a weedy rice population was confirmed in dry-seeded fields. Our objectives were to identify the origins and establishment of this population and pinpoint possible phenotypes involved. We show that California weedy rice is derived from a different genetic source among a broad range of AA genome <i>Oryzas</i> and is most recently diverged from <i>O</i>. <i>sativa</i> temperate <i>japonica</i> cultivated in California. In contrast, other weedy rice ecotypes in North America (Southern US) originate from weedy genotypes from China near wild <i>Oryza</i>, and are derived through existing crop-wild relative crosses. Analyses of morphological data show that California weedy rice subgroups have phenotypes like medium-grain or gourmet cultivars, but have colored pericarp, seed shattering, and awns like wild relatives, suggesting that reversion to non-domestic or wild-like traits can occur following domestication, despite apparent fixation of domestication alleles. Additionally, these results indicate that preventive methods focused on incoming weed sources through contamination may miss burgeoning weedy genotypes that rapidly adapt, establish, and proliferate. Investigating the common and unique evolutionary mechanisms underlying global weed origins and subsequent interactions with crop relatives sheds light on how weeds evolve and addresses broader questions regarding the stability of selection during domestication and crop improvement.</p></div

Population structure as inferred from the best fit number of groupings in InStruct.

<p>Each color indicates genetic membership of the specified number of groups (<i>K</i>). The best fit model had <i>K</i> = 9, shown on the right. <i>K</i> = 8 and <i>K</i> = 10 are included for comparison. <i>K</i> = 4 was the lowest <i>K</i> value maintaining California weedy rice as a separate group. Ln likelihood scores for each <i>K</i> value are shown in parentheses, and likelihood scores for <i>K</i> = 1 through <i>K</i> = 22 are in Table E in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0162676#pone.0162676.s001" target="_blank">S1 File</a>.</p

Average pairwise <i>F</i>_<i>ST</i> estimates between weedy rice sampled in four California fields.

<p>Average pairwise <i>F</i>_<i>ST</i> estimates between weedy rice sampled in four California fields.</p