Submitted to: Cereal Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/15/2002
Publication Date: 11/15/2003
Citation: DOEHLERT, D.C., MCMULLEN, M.S., RIVELAND, N. SOURCES OF VARIATION IN OAT KERNEL SIZE.. CEREAL CHEMISTRY. 2003. VOL. 79:528-534 Interpretive Summary: The size of oat kernels is important to the oat milling industry because the separate oats according to size during the milling process. Oats develop on the oat plant in clusters, called spikelets. Spikelets may contain one, two or three kernels. Our results indicate that the first kernel in these clusters, called the primary kernel is always the largest, and primary kernels from triple kernel spikelets are larger than primary kernels from double kernel spikelets, which are larger than the primary kernel from a single kernel spikelet. Tertiary kernels from triple kernel spikelets are the smallest kernels. Oat milling companies have frequently encouraged oat breeders to select for oat lines with no tertiary kernels because of their presumed association with undersized kernels, unsuitable for milling. However, our results have suggested that environment is a very strong factor affecting the occurrence of tertiary kernels and environments that are favorable for the production of tertiary kernels also favor the production of large kernels. We found no relationship between the frequency of tertiary kernels and the proportion of undersized kernels. In fact, most undersized kernels were found to be kernel classes other than tertiary.
Technical Abstract: Oat kernel size uniformity is important to the oat milling industry because of the size fractionations that occur in the milling process. We measured frequency of single, double and triple kernel spikelets and kernel mass according to kernel order (primary, secondary or tertiary), panicle position, genotype and environment for ten oat cultivars in four locations. Kernel type was the most important factor affecting kernel size, where primary kernels were the largest, and the secondary and tertiary kernels were smaller. Environment was also important. Environments producing larger kernels also produced higher frequencies of triple kernel spikelets. Genotype was also a factor, as some genotypes produced no triple kernel spikelets in any environment, while others produced varying proportions, depending on the environment. Position of the kernels on the panicle also was found to have a minor effect on oat kernel size. Groat percentage of kernel types indicated that larger kernels (within a genotype and location) had lower groat percentages than smaller kernels. The presence of tertiary kernels was neither associated with lower groat percentages, nor with increased proportions of undersized kernels. The majority of undersized kernels in fact were found to be kernel classes other than tertiary.