Adaptive Introgression of Herbivore Resistance Traits in the Weedy Sunflower Helianthus annuus Export

@article{citeulike:683870, abstract = {The role of hybridization in adaptive evolution is contentious. While many cases of adaptive trait introgression have been proposed, the relevant traits have rarely been identified, resulting in a lack of clear examples of this process. Here, we examine a purported case of adaptive introgression in which the annual sunflower Helianthus annuus annuus has captured alleles from a congener (Helianthus debilis) to form a stabilized hybrid, Helianthus annuus texanus. We tested the hypotheses that herbivore resistance traits have introgressed from H. debilis to H. annuus and have increased adaptation in the latter. In two common gardens, fitness (estimated by seed production) was on average 55\% higher in H. a. texanus than in H. a. annuus. For H. a. texanus, three damage traits (of seven tested) differed significantly from the H. a. annuus parent in one or both sites and were shifted in the direction of the more resistant H. debilis. Natural selection favored H. a. annuus × H. debilis BC1 hybrids (synthesized to mimic the ancestors of H. a. texanus) with H. debilis–like resistance to seed midges Neolasioptera helianthis and to receptacle/seed feeding Lepidoptera at one or both sites. Assuming similar herbivore pressures in the past, these results suggest that introgression of biotic resistance traits was important in the adaptation of H. annuus to central and southern Texas.}, author = {Whitney, Kenneth D. and Randell, Rebecca A. and Rieseberg, Loren H.}, citeulike-article-id = {683870}, citeulike-linkout-0 = {http://www.journals.uchicago.edu/AN/journal/issues/v167n6/41433/41433.html}, journal = {The American Naturalist}, keywords = {adaptation-plant, introgression}, pages = {794--807}, posted-at = {2006-06-04 21:17:13}, priority = {2}, title = {Adaptive Introgression of Herbivore Resistance Traits in the Weedy Sunflower Helianthus annuus}, url = {http://www.journals.uchicago.edu/AN/journal/issues/v167n6/41433/41433.html}, volume = {167}, year = {2006} }

TY - JOUR ID - citeulike:683870 L3 - citeulike-article-id:683870 N2 - The role of hybridization in adaptive evolution is contentious. While many cases of adaptive trait introgression have been proposed, the relevant traits have rarely been identified, resulting in a lack of clear examples of this process. Here, we examine a purported case of adaptive introgression in which the annual sunflower Helianthus annuus annuus has captured alleles from a congener (Helianthus debilis) to form a stabilized hybrid, Helianthus annuus texanus. We tested the hypotheses that herbivore resistance traits have introgressed from H. debilis to H. annuus and have increased adaptation in the latter. In two common gardens, fitness (estimated by seed production) was on average 55% higher in H. a. texanus than in H. a. annuus. For H. a. texanus, three damage traits (of seven tested) differed significantly from the H. a. annuus parent in one or both sites and were shifted in the direction of the more resistant H. debilis. Natural selection favored H. a. annuus × H. debilis BC1 hybrids (synthesized to mimic the ancestors of H. a. texanus) with H. debilis–like resistance to seed midges Neolasioptera helianthis and to receptacle/seed feeding Lepidoptera at one or both sites. Assuming similar herbivore pressures in the past, these results suggest that introgression of biotic resistance traits was important in the adaptation of H. annuus to central and southern Texas. JF - The American Naturalist EP - 807 TI - Adaptive Introgression of Herbivore Resistance Traits in the Weedy Sunflower Helianthus annuus VL - 167 SP - 794 KW - adaptation-plant KW - introgression AU - Whitney, Kenneth AU - Randell, Rebecca AU - Rieseberg, Loren PY - 2006/// UR - http://www.journals.uchicago.edu/AN/journal/issues/v167n6/41433/41433.html ER -