Growth Analysis of Isoline-Recurrent Parent Grain Yield Differences in Oats
- M. A. Brinkman and
- K. J. Frey
Growth analysis studies were made on sets of four early and four midseason isolines of oats .(Avena sativa L.) that had significant grain-yield deviations from their recurrent parent in each series. These yield deviations occurred when yield genes, tightly linked to crown rust resistance genes, were transferred from unadapted Avena germplasm into the recurrent parent backgrounds through backcrossing. The higher yielding C.I. 8079- and C.I. 7171-derived isolines had increased growth trait means in each series. Generally, these increases were significant in the early series but not in the midseason series, which also had smaller grain yield increases. C.I. 9170, the early C,L 8079-derived isoline, had a significantly higher leaf area duration (LAD), leaf area ratio (), growth rate (), and relative growth rate () than the early recurrent parent. The midseason C.I. 8079-derived isoline, C.I. 9183, had increases for these traits, but none was significant. Leaf growth increases in the early and midseason C.L 7171-derived isolines, C.L 9178 and C.I. 9188, were very small and presumably did not contribute to the grain yield advantages of these isolines. The low-yielding C.L 7232-derived isolines X550I and C.I. 9192, had significantly lower LAD's, and their 's and 's were reduced, but not significantly.
Although isoline-recurrent parent growth trait differences were not always significant, the trends for these traits in the C.I. 8079- and C.I. 7232-derived isolines, when compared to the recurrent parents, indicated that yield differences within these sets of closely related lines have morpho-physiological causes that can be explained by growth analysis. LAD, , and were growth traits associated with grain yield differences in these isoline-recurrent parent comparisons. However, C.I. 7171-derived isolines had higher grain yields but similar LAD's when compared to their recurrent parents.
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