A chromosome arm from Thinopyrum intermedium × Thinopyrum ponticum hybrid confers increased tillering and yield potential in wheat

Abstract Tiller number is a key component of plant architecture with direct effect on grain yield of wheat. Interspecific hybridization using wild relative species are promising approach for increasing wheat genetic diversity, including yield potential. Agropyron glael, a perennial hybrid of Thinopyrum intermedium and Th. ponticum has five subgenomes (J, J st , J vs , J r , and St), making A. glael an important gene source for transferring useful agronomical traits into wheat. This work reports on development of a wheat- A. glael translocation line WT153397. Sequential in situ hybridizations with J-, St-, and D-genomic DNA probes and pSc119.2, Afa family, pTa71, and (GAA) 7 DNA repeats, as well as an analysis using molecular markers specific for the wheat 6D chromosome, revealed the presence of a 6DS.6J vs centric fusion in the translocation line. Field trials in low-input and high-input breeding nurseries over three growing seasons demonstrated high compensating ability of the Agropyron chromosome arm for the missing 6DL as spike morphology and fertility of WT153397 did not differ significantly from those of wheat parents. Moreover, the introgressed 6J vs chromosome arm significantly increased the number of productive tillers, which manifested in the significantly higher grain yield potential relative to the parental wheat cultivars. The translocated chromosome could be flow-sorted in high purity providing an opportunity to employ chromosome genomics to identify Agropyron gene variant(s) responsible for the tillering capacity. The translocation line WT153397 represents an important genetic stock for functional genetic studies of tiller formation and useful breeding material to increase wheat yield potential.