Research on genetic characteristics of corolla pattern traits in Sinningia speciosa

Sinningia speciosa Benth., one of the earliest commercialized plants in the Gesneriaceae family, is renowned for its rich corolla patterns and vibrant colors. Studying the genetic characteristics of corolla pattern traits in Sinningia speciosa will significantly improve breeding efficiency, facilitate the development of more varieties with diverse floral patterns, and provide guidance for the transformation and innovative utilization of Chinese Gesneriaceae resources.

A comprehensive statistical classification was conducted on 259 accessions from different regions and 1,444 F₁ hybrids derived from complete diallel crosses of 38 distinctive traits. Further selfing identification was performed on F₂ progeny, and combining ability and heritability analyses were carried out based on trait classification to determine the genetic characteristics of these traits.

The main popular traits of Sinningia speciosa include distinctive petal lobe patterns, unique corolla tubes, throat patterns, and semi-double flowers. Popular petal lobe patterns include Pockmarks, stripes, rainbows, white edges, mottling, and staining. Long-tubed corollas are predominantly labiate, while short-tubed corollas are mainly campanulate. In addition to striped throats, colored throats are also distinctive traits of Sinningia speciosa. Selfing progeny analysis revealed that petal patterns such as "Pockmarks" and "stripes," as well as long corolla tubes, exhibit stable inheritance across successive generations. Complete diallel crosses of F₁ and F₂ progeny showed that all distinctive traits followed paternal inheritance, with paternal traits appearing more frequently than maternal traits in F₁/F₂ progeny. The highest probability of producing semi-double flowers was observed in single-petal × double-petal crosses. Among the distinctive traits, the general combining ability (GCA) effects were highest for rainbow rings, Pockmarks, and stripes, which are easier to stabilize and fix in early generations. Broad-sense heritability (H²B) and narrow-sense heritability (H²N) were highest for Pockmarks, rainbow rings, staining, and long tubes, suggesting that trait selection should be conducted in early hybrid generations during breeding.

The genetic characteristics of corolla traits in Sinningia speciosa are complex and diverse. Breeding plans should be tailored based on the genetic properties of these traits to shorten the breeding cycle.