|Goggi, A Susana|
Submitted to: Maydica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/30/2006
Publication Date: 7/30/2007
Citation: Goggi, A., Pollak, L.M., Golden, J.C., Devries, M., McAndrews, G., Montgomery, K. 2007. Impact of early seed quality selection on maize inbreds and hybrids. Maydica. 52:223-233. Interpretive Summary: Seed composition and genetic background influence seed quality, thus influence the stand that farmers obtain in the field. As we combine exotic germplasm with commercial corn to make the crop more nutritious, we are also changing seed quality. Our objective was to characterize a set of high protein commercial lines and their hybrids in order to determine how selecting for higher protein level influenced seed quality and to calculate the breeding parameters for seed quality. We used several seed quality tests used by the industry. The lines had been through an intensive seed qualiity screening during their development, but they still differed for seed quality indicating that there was still genetic differences in this narrow set of germplasm. Breeding parameters indicated that gradual selection would increase seed quality. The high protein was associated with high seed quality, indicating that seed composition does have a large effect on seed quality. These results are important to breeders because we can continue selecting for high protein without damaging seed quality problems. They are important to industry and seed scientists because the influence of the inbred's seed quality on the hybrid has been characterized, by utilizing the index for seed quality. They are important to farmers because they will be able to utilize high protein hybrids for their feed use and in marketing without worrying about a detrimental influence on plant stand.
Technical Abstract: Seed composition and genetic background influence seed quality. Plant breeders seldom select or evaluate their inbreds on the basis of seed quality characteristics that could prevent poor germination and field emergence. The standard germination test evaluates seed viability, but it often overestimates field performance. Therefore, seed vigor tests are used to predict seed germination under stressful environments. The objectives of this study were 1) to evaluate the seed quality attributes of a group of maize (Zea mays L.) inbreds selected for high protein content; 2) to assess whether early selection improves the overall seed quality and decreases the phenotypic variability in a group of inbreds; and 3) to calculate the breeding parameters of general (GCA) and specific combining ability (SCA). During summer 2002 and 2003, related sets of inbred lines were grown in identical nurseries near Clinton, IL, and Ames, IA. Seed from each inbred was produced by self pollination. Some of the inbred lines grown in 2002 and all grown in 2003 were high-protein white lines that also had been selected for cold tolerance and high post-accelerated aging field emergence. In 2002, the mean percentage of standard germination test, saturated cold test, accelerated aging test, soak test, and fast green test for the group of selected high-protein white inbreds were significantly higher than the average of the yellow checks. In 2003, the selected inbreds and check lines were high-protein white inbreds. Seed quality of the selected inbreds was not significantly different from the checks. Even after a very intense selection process for seed quality traits, there was genetic variability for seed quality in these sets of high protein white inbreds. GCA effects for seed quality were more important than the SCA effects, indicating that the additive effect of the inbreds was more important to the final seed quality of the hybrids. Selecting inbreds for high seed quality early in the breeding program is beneficial and worth the extra time, especially when working with wide breeding crosses such as white x yellow maize.