Heteroic Responses in Oats 1

Yield, yield components, and subcomponents were measured in spaced, F 1 plants of 72 oat crosses. Heterosis was studied as a percent of the mid‐parent, as a percent of the high‐parent, and by the number of crosses in which the F 1 average was greater than the high parent average or less than the low parent average. Comparisons, between characters, of mid‐parent heterosis percentages were found to be invalid because they were masked by differences in the variability of the characters. High‐parent heterosis was exhibited for yield but not for the components, i.e., panicles per plant, seeds per panicle, and weight per seed. Seeds per panicle, although the most variable character, exhibited the least heterotic response. Heterotic responses for yield were positively associated with those for panicles per plant and seeds per panicle, and negatively associated with weight per seed responses. Panicles per plant responded independently from seeds per panicle and weight per seed, and a negative relationship was found between seeds per panicle and weight per seed responses. Weight per groat responses were positively associated with those of the sub‐components, groat length and width, and length and width responded independently.