Data from: Life history traits and phenotypic selection among sunflower crop-wild hybrids and their wild counterpart: implications for crop allele introgression

Hybridization produces strong evolutionary forces. In hybrid zones, selection can differentially occur on traits and selection intensities may differ among hybrid generations. Understanding these dynamics in crop-wild hybrid zones can clarify crop-like traits likely to introgress into wild populations and the particular hybrid generations through which introgression proceeds. In a field experiment with four crop-wild hybrid Helianthus annuus (sunflower) cross types, we measured growth and life history traits and performed phenotypic selection analysis on early season traits to ascertain the likelihood, and routes, of crop allele introgression into wild sunflower populations. All cross types overwintered, emerged in the spring, and survived until flowering, indicating no early life history barriers to crop allele introgression. While selection indirectly favored earlier seedling emergence and taller early season seedlings, direct selection only favored greater early season leaf length. Further, there was cross type variation in the intensity of selection operating on leaf length. Thus, introgression of multiple early season crop-like traits, due to direct selection for greater early season leaf length, should not be impeded by any cross type and may proceed at different rates among generations. In sum, alleles underlying early season sunflower crop-like traits are likely to introgress into wild sunflower populations.杂交作用可产生强劲的进化动力。在杂交区带中，自然选择可对不同性状产生差异化作用，且不同杂交世代间的选择强度也可能存在差异。解析作物-野生向日葵（Helianthus annuus）杂交区带中的这类动态，可明确哪些类作物性状更有可能渐渗进入野生种群，以及渐渗过程所依托的特定杂交世代。本研究针对4种作物-野生向日葵杂交组合类型开展田间试验，测定了生长与生活史性状，并对早季性状进行表型选择分析，以明确作物等位基因渐渗进入野生向日葵种群的可能性与具体路径。所有杂交组合均成功越冬、春季出苗并存活至开花期，表明作物等位基因渐渗未受到早期生活史阶段的阻碍。尽管间接选择倾向于更早的幼苗出苗时间以及更高大的早季幼苗，但直接选择仅青睐更长的早季叶片长度。此外，针对叶片长度的选择强度在不同杂交组合间存在差异。因此，由于直接选择倾向于更长的早季叶片长度，多个类作物早季性状的渐渗不会受到任何杂交组合的阻碍，且在不同世代间的渐渗速率可能存在差异。综上，控制向日葵类作物早季性状的等位基因，极有可能渐渗进入野生向日葵种群。