Genetic mapping of a fertile tiller inhibition gene, ftin, in wheat

Abstract

Increased fertile tiller number is a very important trait in high-yielding wheat (Triticum aestivum L.) lines. Uncovering the fundamental biological progress of fertile tiller formation would improve our understanding of the genetic nature of this trait and increase wheat yield. However, there is no suitable genetic material for studying the genetic mechanism of wheat fertile tiller formation. We report here the development of a fertile tiller inhibition line, Pubing3558, which was derived from a cross between common wheat and wild grass Agropyron cristatum. Pubing3558 possesses normal tillering ability in the seedling stage but reduced fertile tiller formation in the reproductive growth phase. A cross between Pubing3558 and the wheat cultivar Jing4841 with multiple fertile tillers was performed in order to map the fertile tiller inhibition gene (ftin). The F1 population of the cross between Pubing3558 and Jing4841 showed a normal phenotype similar to that of the parent Jing4841. The F2 population segregated with a 3:1 Mendelian ratio in 2-year replicates, which was further proven by the segregation ratio of the F3 population. Genetic analysis uncovered that the fertile tiller inhibition trait in Pubing3558 is controlled by a single recessive gene. Using bulked segregant analysis methods, we located the ftin gene on wheat chromosome 1AS, which is linked closely to markers Xcfa2153 at a genetic distance of 1.0 cM. A combination of phenotype tests and genetic mapping demonstrated that the ftin gene is a newly identified gene in wheat. Overall, our results suggest that Pubing3558 will be valuable genetic source for studying the biological process of fertile tiller formation.