Selection for High Specific Gravity in Oat Populations Heterogeneous for Naked Genotypes
- Brenda J. Lanini and
- H. G. Marshall
The nutritive value of oat (A vena sativa L.) grain could be improved by the development and use of naked-seeded cultivars of A vena nuda L. Hulled types predominate in heterogeneous populations during generations of inbreeding, and this reduces the effective population size for selection of superior naked genotypes. Our objectives were to apply repeated cycles of selection for high specific gravity seed to bulk populations and determine the effects on the percentage of naked seed, grain test weight, and average groat weight. A specific gravity grader was used to apply two cycles of selection pressure to four bulk populations that were relatively homozygous (F6 to F8) but heterogeneous for the N gene (naked seed), as well as a fifth population homozygous for that gene. The original (0) and derived subpopulations were compared in replicated 5-row plots in a split-plot design near University Park, PA, during 1985. Increases in the amount of naked seed ranged from 23 to 134% above the 0 populations after one cycle of selection. With the exception of Population 5, a second cycle further increased the percentage of naked seed to amounts ranging from 25 to 209% above the 0 populations. Each cycle of selection increased grain test weight of all populations except Population 5, where two cycles were required to increase the trait. One cycle of selection did not change groat weight, but there was 3.9% increase after two cycles of selection. Natural selection caused significant decreases in the percentage of naked seed in four of the populations (15 to 35%), but other traits were not affected. In conclusion, selection for high specific gravity separated naked from hulled seeds and rapidly increased the frequency of naked-seeded plants in oat populations that were heterogeneous for the N gene.
Copyright © 1990.