| natural variation in gene expression between wild and weedy populations of helianthus annuus. | the molecular genetic changes underlying the transformation of wild plants into agricultural weeds are poorly understood. here we use a sunflower cdna microarray to detect variation in gene expression between two wild (non-weedy) helianthus annuus populations from utah and kansas and four weedy h. annuus populations collected from agricultural fields in utah, kansas, indiana, and california. when grown in a common growth chamber environment, populations differed substantially in their gene expre ... | 2008 | 18689879 |
| low intraspecific variation for genomic isolation between hybridizing sunflower species. | barriers to gene flow between species result from selection against foreign linkage blocks in hybrids. when the geographic ranges of taxa meet at multiple locations, the opportunity exists for variation in the genetic architecture of isolating barriers. hybrid zones between two sunflower species (helianthus annuus and h. petiolaris) in nebraska and california exhibited remarkably similar patterns of introgression of mapped molecular markers. congruence among hybrid zones may result from limited ... | 2001 | 11392386 |
| revisiting a classic case of introgression: hybridization and gene flow in californian sunflowers. | during invasion, colonizing species can hybridize with native species, potentially swamping out native genomes. however, theory predicts that introgression will often be biased into the invading species. thus, empirical estimates of gene flow between native and invasive species are important to quantify the actual threat of hybridization with invasive species. one classic example of introgression occurs in california, where helianthus bolanderi was thought to be a hybrid between the serpentine e ... | 2016 | 26840428 |
| entyloma helianthi: identification and characterization of the causal agent of sunflower white leaf smut. | white leaf smut is a minor foliar disease of sunflower (helianthus annuus) in the united states. the disease occurs primarily in greenhouse-grown sunflowers in california and causes leaf spot, defoliation, and a reduction in yield and crop value. historically, many entyloma specimens with similar morphological characters, but infecting diverse plant genera including helianthus, were called entyloma polysporum. recent comparative morphological and molecular work has shown that entyloma species in ... | 2017 | 28854121 |
| sunflower (helianthus annuus) pollination in california's central valley is limited by native bee nest site location. | the delivery of ecosystem services by mobile organisms depends on the distribution of those organisms, which is, in turn, affected by resources at local and landscape scales. pollinator-dependent crops rely on mobile animals like bees for crop production, and the spatial relationship between floral resources and nest location for these central-place foragers influences the delivery of pollination services. current models that map pollination coverage in agricultural regions utilize landscape-lev ... | 2016 | 27209786 |