Date of Award
Master of Science
John H. Reynolds, B. N. Duck
A diallel cross with reciprocals was performed on eleven buffalo alfalfa clones to investigate seed set differences. Seeds per pod, seeds per flower, and percentages of flowers setting pods were measured foreach cross and reciprocal. A dial lei analysis was performed for each character. Significant general effects were detected for each character when expected mean squares proposed by Nyquist (1966) were used to determine appropriate F-ratios. No significant general effects were detected when expected mean squares proposed by Cockerham (1963) were used.
Significant specific effects were detected only for seeds per pod.Maternal effects were significant for all three characters. Reciprocal Effects were significant for seeds per flower and percentages of flowers setting pods. The significance of these effects was unaltered by the differences in expected mean squares from the two methods of analysis.
Estimated variance components differed when the expected mean squares proposed by Nyquist and Cockerham were used in the computations.Specific effects made the largest contribution to the variance for seeds per pod with both sources of expected mean squares. General effects were the largest contributor to variances for seeds per pod and percentages of flowers setting pods when the method of Nyquist was used. When the method of Cockerham was used, reciprocal and maternal effects, respectively,made the largest contribution to variances for seeds per flower and percentages of flowers setting pods
.The results indicated that the alfalfa breeder should selectfor seed set when selecting parents for hybrid varieties. The combination of effects found in this study could be used more efficiently with hybrid than with synthetic varieties.
Rice, James S., "The relation of general, specific, maternal, and reciprocal effects to seed set differences in a diallel cross among eleven clones of Buffalo alfalfa (Medicago sativa L.). " Master's Thesis, University of Tennessee, 1968.