Impact of different cms types on grain yield of dent X flint hybrids of maize (Zea mays L.)

Cytoplasmic male sterility (cms) is an interesting trait for the maize seed industry, leading to lower costs for the production of hybrid seed by eliminating the labor-intensive mechanical emasculation of the seed parent line. In recent years most hybrid seeds based on a male-sterile inbred line are produced with the major cms types cms-C and cms-S, replacing cms-T, which is susceptible to Southern Corn Leaf Blight. There is very little knowledge on the effect of these different cms types on the yield of modern hybrids. The present study was carried out in 1999 and 2000 in the southern part of Switzerland to investigate the general impact of cms on yield as well as the specific effects of different cms types. A set of hybrid combinations of Corn Belt dent lines and modern European flint lines was used. In general, cms had a positive effect on the yield of all the tested hybrids in both years. In the high yielding year 1999 all the tested hybrids with cms-C cytoplasm yielded higher than hybrids with cms-S cytoplasm. In 2000, when yields were low due to unfavorable weather conditions, all the cms cytoplasm similarly contributed to an increased yield consistency.