Application and prospects of Suwan germplasm in maize breeding in China

Tropical maize germplasm, such as Suwan, offers significant advantages including rich genetic diversity, strong stress resistance, and high combining ability, making it highly valuable for broadening the genetic base of maize in China. It holds great importance for stress-resistant breeding and the development of high-yielding hybrid combinations. However, such germplasm also exhibits strong photoperiod sensitivity, delayed maturity, and excessive vegetative growth under temperate conditions, which greatly restrict its direct utilization. To overcome these limitations, this study reviews Suwan germplasm from the perspective of “temperate-tropical germplasm integration and domestication”. It systematically summarizes its origin and genetic characteristics, elucidates adaptation strategies under long-day conditions, and outlines the development of synthetic temperate-tropical populations as well as the practical outcomes of north-south shuttle breeding. On this basis, the photoperiod and temperature sensitivity of tropical germplasm have been markedly improved, facilitating the introgression of superior alleles into temperate maize. This provides both theoretical foundations and methodological support for the efficient integration and genetic innovation of tropical and temperate maize germplasm, thereby further expanding and enriching the genetic base of maize in China.