Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/25/2002
Publication Date: 1/1/2003
Citation: FLINT-GARCIA, S.A., JAMPATONG, C., DARRAH, L.L., MCMULLEN, M.D. QUANTITATIVE TRAIT LOCUS ANALYSIS OF STALK STRENGTH IN FOUR MAIZE POPULATIONS. CROP SCIENCE. 2003. v. 43. p. 13-22. Interpretive Summary: Stalk lodging in corn is the breakage of the corn stalk at or below the ear which results in the loss of the ear at harvest. Stalk lodging causes significant losses each year in the United States. Selection for rind penetrometer resistance has proven useful in enhancing germplasm for stalk strength, and therefore improving stalk lodging resistance. Very little is sknown about the genetics underlying stalk strength. In this research we determined the genetic complexity of stalk strength as measured by rind penetrometer resistance. We found that many genes are responsible for stalk strength. Some of the genes we identified may control lignin synthesis and the timing of developmental changes during the growth of the corn plant. This information will be important to researchers in their attempts to understand the biochemistry of stalk strength and to corn breeders to develop corn lines the reduce the amount of stalk lodging experienced by farmers in their fields.
Technical Abstract: Stalk lodging in maize (Zea mays L.) causes losses estimated to range from 5 to 20% annually in the United States. Selection for rind penetrometer resistance (RPR) has proven useful in enhancing germplasm for stalk strength, and therefore improving stalk lodging resistance. We conducted quantitative trait locus (QTL) analysis for RPR in four F2:3 populations. Means combined over environments were used as trait data for composite interval mapping using QTL Cartographer. Eight, ten, eight, and nine single-effect QTL and four, two, zero, and five epistatic interactions were detected for RPR in the four populations. These data clearly indicate the complex nature of stalk strength. Multi-locus models, including the single-effect QTL and epistatic interactions, accounted for 33.4%, 44.7%, 48.4%, and 58.7% of the phenotypic variation. One chromosomal region contained a QTL from all four populations, while two QTL were in common among three of the four populations and five QTL were in common between tw populations. Candidate genes that overlap QTL confidence intervals include those involved in lignin synthesis, the phenylpropanoid pathway, and the timing of vegetative phase change.