Influence of Cytoplasmic Male Sterility on Grain Yield of the “Turda” Maize Hybrids under Different Environmental Conditions

In recent decades, little attention has been paid to using cytoplasmic male sterility (CMS) in maize hybrid seed production. Cytoplasmic male sterility is important for seed production of maize hybrids because CMS seeds are relatively inexpensive. The trait (CMS) is reversible and can be restored to fertility in the presence of nuclear restorer genes (Rf genes). There is very little knowledge about the effect of these different CMS types on the grain yield of modern hybrids. The present study was carried out in 2021, 2022 and 2023 in the central part of Romania, to investigate the specific impact of CMS on grain yield and other agronomic traits. 10 single-cross hybrids were tested, four of which were recently registered. Generally, CMS cytoplasm significantly negatively affected the yield of the hybrids tested over the three years. In 7 of the 10 hybrids tested, CMS cytoplasm influenced the insignificant decrease in average yield. In the higher-yielding 2021, only two hybrids tested with cms-C cytoplasm had a higher yield than hybrids with isogenic fertile cytoplasm. In 2022 and 2023, when yields were significantly reduced, due to water and high temperature stress conditions, the yield of the four tested hybrids with cms-C cytoplasm was higher than isogenic fertile cytoplasm. Recently developed hybrids: Turda 2020 and SURO 11 had the highest average grain yields, and the difference in yield between hybrids with CMS cytoplasm and those with isogenic fertile cytoplasm was non-significant. Therefore, for some hybrids in which the differences in grain yield between the CMS cytoplasm and the normal type were insignificant, in this case, we recommend the production of maize hybrid seeds based on the CMS cytoplasm.