Long‐term persistence of crop alleles in weedy populations of wild radish (Raphanus raphanistrum)

Abstract

Summary• Hybridization allows transgenes and other crop alleles to spread to wild ⁄ weedy populations of related taxa. Researchers have debated whether such alleles will persist because low hybrid fitness and linkage to domestication traits could severely impede introgression.• To examine variation in the fates of three unlinked crop alleles, we monitored four experimental, self-seeding, hybrid populations of Raphanus raphanistrum · Raphanus sativus (radish) in Michigan, USA, over a decade. We also compared the fecundity of advanced-generation hybrid plants with wild plants in a common garden experiment.• Initially, F 1 hybrids had reduced fitness, but the populations quickly evolved wild-type pollen fertility. In Year 10, the fecundity of plants from the experimental populations was similar to that of wild genotypes. Crop-specific alleles at the three loci persisted for 10 yr in all populations, and their frequencies varied among loci, populations and years.• This research provides a unique case study of substantial variation in the rates and patterns of crop allele introgression after a single hybridization event. Our findings demonstrate that certain crop alleles can introgress easily while others remain rare, supporting the assumption that neutral or beneficial transgenes that are not linked to maladaptive traits can persist in the wild.

Selection on Crop-Derived Traits and QTL in Sunflower (Helianthus annuus) Crop-Wild Hybrids under Water Stress

“…Another consequence of small sample size is the potential for the detection of false positive QTL [74], but the generation of permutated significant LOD values is an accepted method to account for this [75]. Importantly, the additive effect of the crop-derived allele in our study was in the same direction as predicted from the selection analysis for approximately half the QTL (excluding water content and fecundity QTL) detected in the LW treatment, suggesting that the repeated detection of selection favoring crop-derived alleles may be advantageous under a broader range of natural conditions than otherwise thought [14] [15].…”

“…Studies in sunflower have suggested that crop-like traits (i.e., earlier flowering time and a larger primary inflorescence) increase reproductive output in crop-wild hybrids under a range of natural conditions [12] [13]. Crop-derived alleles have been known to persist within wild populations for at least five generations following hybridization in sunflower [14] and ten generations in wild radish [15], suggesting that some crop-derived alleles may persist in the wild, contrary to expectation. Indeed, crop-derived alleles may have also contributed to the evolution of weediness in wild sunflower [16].…”

Little White Lies: Pericarp Color Provides Insights into the Origins and Evolution of Southeast Asian Weedy Rice

“…If Malaysian weeds are, in fact, a crucible where crop and wild alleles can recombine, the weeds could also potentially serve as a bridge for the introduction of crop alleles into wild populations (Snow et al 2010; Campbell et al 2016) or vice versa (Félix et al 2014). Of these two gene flow possibilities, wild-to-crop gene flow may be the less serious problem.…”

The Effect of Altered Soil Moisture on Hybridization Rate in a Crop-Wild System (Raphanus spp.)

“…sativus ) and its wild, weedy relative ( R . raphanistrum ), but generally, risk assessments have only considered physical and phenological separation, as well as genetic compatibilities [28, 47, 74]. For instance, hybridization rates between cultivated and wild R .…”