Diverse and Stable Male Sterile Tropical Asian Maize Hybrids Reveal Grain Yield Increases

Abstract Cytoplasmic Male Sterility, a maternally inherited trait which suppresses the production of viable pollen, eliminates the need for detasseling of females in hybrid maize seed production. We report a 9.9% yield advantage of a maize hybrid with the C-type male sterile cytoplasm compared to its isogenic non-CMS counterpart through a head-to-head analysis. From implications in enhancing global genetic gains to addressing issues of labour availability and rising wages, the technology reveals opportunities for intellectual property protection and region-wide taming of diversity of tropical Asian maize germplasm by imposing a heterotic discipline. A set of 88 diverse elite CIMMYT Asia maize inbred lines converted to CMS using a temperate donor, were evaluated for stable per se performance for grain yield, male sterility and Turcicum Leaf Blight resistance. Performances of hybrids of varied genetic backgrounds across diverse environments -- seasons, years, agroecologies, countries, abiotic- and biotic stresses -- established a stable and robust diversification process which included the identification of potential maintainers and restorers that will benefit researchers, the seed industry and farmers.