Relative Productivity of Homogeneous and Heterogeneous Oat Cultivars in Optimum and Suboptimum Environments
1967
Frey, K. J. | Maldonado, Uriel
We tested six oat cultivars and the 57 mixtures among them for yield at two sowing dates (early and late) for 3 years. The mean relative yield (actual yield of mixture divided by mean yield of component cultivars) of all mixtures was 100% at the first sowing date and 104% at the second. The advantage of heterogeneous oat populations increased as the environment became more stressed. At the first date, the relative yield of only one mixture was significantly better than expected, whereas at the second date eight were significantly better. The interaction variances for “dates Χ cultivars” and “dates Χ mixtures of two cultivars” were highly significant, but none of the interactions of “date Χ mixtures of three, four, or five cultivars” was significant. This indicates that the mixtures of cultivars gave more stable production when tested across sowing dates than did cultivars. There was no association between the number of cultivars in mixtures and the grain yields of the mixtures. Several mixtures yielded more than the best cultivar when averaged across both environments.
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