The frequent transition from outcrossing to selfing in flowering plants is often accompanied by changes in multiple aspects of floral morphology, termed the “selfing syndrome.” While the repeated evolution of these changes suggests a role for natural selection, genetic drift may also be responsible. To determine whether selection or drift shaped different aspects of the pollination syndrome and mating system in the highly selfing morning glory Ipomoea lacunosa, we performed multivariate and univariate Qst-Fst comparisons using a wide sample of populations of I. lacunosa and its mixed-mating sister species I. cordatotriloba. The two species differ in early growth, floral display, inflorescence, corolla size, nectar, and pollen number. Our analyses support a role for natural selection driving trait divergence, specifically in corolla size and nectar traits, but not in early growth, display size, inflorescence size, or pollen traits. We also find evidence of selection for reduced herkogamy in I. lacunosa, consistent with selection driving both the transition in mating system and the correlated floral changes. Our research demonstrates that while some aspects of the selfing syndrome evolved in response to selection, others likely evolved due to drift or correlated selection, and the balance between these forces may vary across selfing species.
Table_of_accessions
A table listing all accessions used in this study with latitude and longitude data.
Leaf_scoring_figure
Images of an entire and lobed leaf, corresponding to points 0 and 1 on our leaf-scoring scale.
ANOVA_additional_effects
Restricted estimation maximum likelihood effects for the site and female parent random effects from the nested ANOVA on phenotypic traits.
G-matrix_tables
The G-matrices used in our estimation of rho-obs.
CleanIndividualMeans3-7-2018No51Or115
Final combined individual floral trait measurements. All individual measurements. Sheets: FloralMeasurements (all individual floral measurements); Counts (tracking number of flowers sampled from each individual across all sheets); PollenCollections (collections of total pollen from individual with date); Measurement_Defs (definitions of all floral measurements)
Floral_traits_final_with_Irene
Floral_traits_final_with_Irene.xlsx" Final combined individual floral trait measurements. All individual measurements. Sheets: FloralMeasurements (all individual floral measurements); Counts (tracking number of flowers sampled from each individual across all sheets); PollenCollections (collections of total pollen from individual with date); Measurement_Defs (definitions of all floral measurements)
FstQst Nectar Measurements
FstQst Nectar Measurements.xlsx" Irene's spreadsheet of individual nectar measurements. Each row is an individual flower. Columns: Date (measurement date) # (sample of day) Time (Measurement time) Individual (Individual ID number) Infl. # pos (position on inflorescence) Sepal Length (length of a sepal) Cor. Length (tissue length of the corolla) Style Length (length of the style from the ovary to the stigma) Nectar (UNC) (length of nectar in capillary tube) Sugar (UND) (concentration of undiluted nectar) Sugar (D+2.5) (concentration of nectar diluted with 2.5uL water)
Internodes_170206
Internodes_170206.xlsx" Final spreadsheet of all internode measurements. Rows indicate individuals. Columns: Year (year of planting) Family (individual identity number) Species (Ipomoea cordatotriloba, I. lacunosa, I. leucantha, or I. austinii) Female (the accession the seeds were derived from) Individual (individual's identity number) Replanted (whether the original seed failed to germinate and, if so, when it was replaced) Internode1 (length of stem from cotyledons to first true leaf, measured on day 21 from planting) Internode2 (length of stem from first true leaf to second true leaf, measured on day 21 from planting) Internode3 (length of stem from second true leaf to third true leaf, measured on day 21 from planting). Also includes notes on trichomes ("hairy!") and average values for all four species.