Month: September 2022

DISTINCT SPECIES PROPERTIES. "Such properties can, for example, include a distinct genepool or adaptation to a different habitat. Furthermore, the group should already share a common evolutionary history or have the potential to diverge." https://lnkd.in/dK-A3iM View in LinkedIn

CONSERVATIVE TAXA ASSIGNMENT. "Hybrids growing in sympatry with their parents cannot necessarily be assumed to have a distinct genepool, and even if certain hybrids show higher fitness than the parents, it needs to be demonstrated that they have the potential to evolve into a coherent group under natural conditions. Before evidence has been collected in this regard, hybrids should rather be recorded as such rather than described as a taxon." https://lnkd.in/dK-A3iM View in LinkedIn

REASSIGNED RHODODENDRON SPECIES. "Together, the two species investigated here have nine described infraspecific taxa: five for R. delavayi, and four for R. irroratum, however, these are all assigned the rank of subspecies." https://lnkd.in/dK-A3iM View in LinkedIn

TRANSGRESSIVE PROBLEM. "A further problem can arise from transgressive characters, meaning traits that are not seen in either parent. Transgressive characters can already occur at a lower frequency in F1 hybrids, but are frequently reported in later generation hybrids." https://lnkd.in/dK-A3iM View in LinkedIn

TRANSGRESSIVE CHARACTERISTICS. “Studies of quantitative traits in segregating hybrid populations sometimes report the presence of phenotypes that are extreme relative to those of either parental line. The generation of these extreme phenotypes is referred to as transgressive segregation, and this is a major mechanism by which extreme or novel adaptations observed in new hybrid ecotypes or species are thought to arise.” https://lnkd.in/d4xXNs5 View in LinkedIn

TRANSGRESSIVE CHARACTERISTICS. “Studies of quantitative traits in segregating hybrid populations sometimes report the presence of phenotypes that are extreme relative to those of either parental line. The generation of these extreme phenotypes is referred to as transgressive segregation, and this is a major mechanism by which extreme or novel adaptations observed in new hybrid ecotypes or species are thought to arise.” https://lnkd.in/d4xXNs5 View in LinkedIn

“TRANSGRESSIVE SEGREGATION appears to be ubiquitous in plant hybrids.” More so than in animals. http://www.nature.com/hdy/journal/v83/n4/full/6886170a.html?foxtrotcallback=true View in LinkedIn

BLURRED SPECIES LINES. "It is nowadays evident that hybridization is widespread in certain groups of organisms, and the boundaries between varieties and species can be blurred in complexes of closely related species." https://lnkd.in/dK-A3iM View in LinkedIn

SO ENDS this first weekend contemplation of plant hybrids. Historical reversals of plant species assignments have not been rare, and the case study of the rampantly hybrid species rhododendron through an exhaustive study of traits illustrate how slippery the assignments can be. This is further confounded by transgressive segregation which is the formation of extreme phenotypes when compared to the parental lines, making the hybrid resemble a new species. https://lnkd.in/ddar4m9 View in LinkedIn

HETEROSTYLY AND COMPATIBILITY. “The lengths of stamens and pistils in heterostylous flowers are adapted for pollination by different pollinators, or different body parts of the same pollinator. Thus, pollen originating in a long stamen will reach primarily long rather than short pistils, and vice versa. When pollen is transferred between two flowers of the same morph, no fertilization will take place, because of the self-incompatibility mechanism.” https://en.m.wikipedia.org/wiki/Heterostyly View in LinkedIn