Relative Yields of Mixtures and Monocultures of Oat Genotypes1
- R. Shorter and
- K. J. Frey2
We evaluated relative yields of mixtures and monocultures of eight cultivars and 20 random F9-derived oat (Avena sativa L.) lines from a bulk population at two locations for 2 years. Three diallel sets of two-component mixtures were constructed: 378 1:1 mixtures among 28 lines, as well as 105 1:3 mixtures among 15 lines (four cultivars and 11 random lines). The 28 oat lines also were mixed in a 1:1 frequency with each of six testers (homogeneous and heterogeneous at low, medium, and high grain yield levels) to identify lines forming high yielding mixtures.
General mixing ability was significant (P ≤ 0.01) for grain and straw yields and specific mixing ability was not. Of the 1:1 mixtures, 321 for grain yield and 305 for straw yield were not significantly different (P ≤ 0.05) from their component means. Only 15 1:1 mixtures for grainyield and .10 for. straw yield, significantly (P ≤ 0.05) outyielded thexr higher yielding component (by to 11% for grain and 15% for straw). Cultivar mixtures exceeded their component means by up to 7% for grain or straw yield whereas random line mixtures were superior to their component means by up to 13% for grain yield and 17% for straw yield. Grain or straw yield differentials between mixtures and their components in monoculture generally had repeatability of 0 to 32% over environ. ments.
Seven (for grain) and five (for straw) mixtures out of 105 used in the component.frequency experiment had significant (P ≤ 0.05) linear effects across component frequencies, and none had significant quadratic effects for either trait, indicating that mixture components interacted additively. Line performances in monoculture and in 1:1 mixtures were significantly correlated (r = 0.91 for both grain and strawyield (P ≤ 0.05). For both traits, the highest yielding mixtures were not superior to either their higheryieldin.g component or the fine with the highest monoculture y~eld. Therefore, use of mixtures of oat cultivars or lines to obtain a yield advantage over monocultures would not be justified.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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