DIALLEL ANALYSIS OF FLOWERING-TIME IN CORN (ZEA MAYS) USING A CORN HEAT UNIT TRANSFORMATION

1980 ◽  
Vol 22 (4) ◽  
pp. 633-640 ◽  
Author(s):  
S. B. Rood ◽  
D. J. Major
Keyword(s):  
Zea Mays ◽  
Flowering Time ◽  
Combining Ability ◽  
Zea Mays L ◽  
Diallel Analysis ◽  
Diallel Cross ◽  
Specific Combining Ability ◽  
Dominance Model ◽  
Genetic Interpretation ◽  
Array Position

A set of eight corn (Zea mays L.) inbreds was studied in a diallel cross over two years and in a growth room to investigate general and specific combining ability for flowering-time. Diallel analysis of days from emergence to flowering revealed a failure of the joint Wr/Vr regression in one of the years, indicating a lack of agreement with the simple additive-dominance model of inheritance. The array position changed across the years and environments, complicating genetic interpretation. Transforming data of flowering-time to cumulative corn heat units (CHU) to flowering gave a better fit. Joint regression was satisfactory and array position was more consistent across years and environments. Dominance was incomplete for low CHU to flowering. Positive (increasing CHU) and negative, as well as dominant and recessive, alleles were in about equal frequencies. Heritability estimates in the broad- and narrow-sense were high. The estimates of general combining ability were higher than the estimates of specific combining ability in all studies.

Diallel analysis of yield and yield components of winged bean (Psophocarpus tetragonolobus (L.) D.C.)

1986 ◽  
Vol 106 (3) ◽  
pp. 485-490 ◽  
Author(s):  
H. N. De Silva ◽  
A. Omran
Keyword(s):  
Grain Yield ◽  
Combining Ability ◽  
Yield Components ◽  
Diallel Analysis ◽  
Diallel Cross ◽  
Winged Bean ◽  
Specific Combining Ability ◽  
Psophocarpus Tetragonolobus ◽  
Equal Importance ◽  
Yield And Yield Components

SummaryThe variability revealed in a half-diallel cross between nine diverse genotypes of winged bean (Psophocarpus tetragonolobus (L.) D.C.) in regard to yield and yield components was studied in the F1 generation. The results indicated that high genetic variability existed for all traits. With respect to seed size, general combining ability effects alone were adequate to predict the performance of hybrids. For numbers of pods per plant and seeds per pod, both general and specific combining ability effects were of equal importance, while the performance of hybrids for grain yield was mainly dependent on specific combining ability effects. Heterosis was clearly evident for number of seeds per pod and grain yield. Of the yield components, number of pods per plant exhibited a positive genotypic association of appreciable magnitude with grain yield, showing its usefulness as an indicator of yield in selection.

EVALUATION OF THE ASSUMPTIONS REQUIRED FOR THE GENETIC INTERPRETATION OF DIALLEL EXPERIMENTS IN SELF-POLLINATING CROPS

1977 ◽  
Vol 57 (4) ◽  
pp. 1185-1191 ◽  
Author(s):  
M. J. SOKOL ◽  
R. J. BAKER
Keyword(s):  
Combining Ability ◽  
Gene Frequency ◽  
Gene Action ◽  
Diallel Analysis ◽  
General Combining Ability ◽  
Specific Combining Ability ◽  
Genetic Models ◽  
Gene Frequencies ◽  
Dominance Interaction ◽  
Genetic Interpretation

Simulation of two-locus genetic models was used to investigate the effects of gene frequency, non-random association of genes, and epistasis on the interpretation of diallel experiments in self-pollinating crops. It was demonstrated that general combining ability includes effects due to additive, epistatic, and, when gene frequencies are not equal to 0.5, dominance gene action. Similarly, when gene frequencies do not equal 0.5, average heterosis depends upon additive × dominance interaction as well as dominance and dominance × dominance interaction. Negative associations between genes greatly inflate the apparent amount of specific combining ability. These findings cast serious doubt on the utility of diallel analysis for studying the genetics of self-pollinating crops.

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