scholarly journals Diallel Analysis of Diplodia Ear Rot Resistance in Maize

Plant Disease ◽  
1998 ◽  
Vol 82 (6) ◽  
pp. 699-703 ◽  
Author(s):  
A. E. Dorrance ◽  
K. H. Hinkelmann ◽  
H. L. Warren

A diallel cross of seven inbreds and one synthetic line of maize were analyzed in 1994 and 1995 for their reaction to Diplodia ear rot. An additional inbred line was included in the 1995 analysis. Plants were inoculated by placing a pycnidiospore suspension (5 × 103 spores per ml) of Stenocarpella maydis in the whorl at the V14 to V15 growth stage. Crosses were evaluated for disease incidence of Diplodia ear rot at harvest, and the percentage of plants with Diplodia ear rot in a plot was used for analysis. In both years, general combining ability (GCA) effects were significant. In 1995, specific combining ability effects were also significant. There were no reciprocal effects. There was no significant interaction between year and genotypes, indicating that crosses reacted the same in both years. Inbred lines B37, H111, B68, and MS had negative GCA effects that contributed toward resistance in both years. VA26, with intermediate resistance to Diplodia ear rot, contributed toward susceptibility. Only inbred lines with a high degree of resistance should be used as parents.

1992 ◽  
Vol 72 (3) ◽  
pp. 915-923 ◽  
Author(s):  
L. M. Reid ◽  
D. E. Mather ◽  
R. I. Hamilton ◽  
A. T. Bolton

Thirty-seven maize inbreds and a diallel cross of 12 inbreds selected from the 37 were evaluated at each of two locations for resistance to Fusarium graminearum ear rot infection via the silk and/or silk channel. Artificial inoculation was accomplished with a spore suspension injected into the silk channel of individual ears. Mean disease ratings, made on a scale of 1–7, revealed that most of the 37 inbreds were susceptible. Twelve of the inbreds, chosen to represent a range of susceptibility, were intercrossed in a complete diallel arrangement. Disease incidence and severity in the parents, crosses and reciprocals were evaluated in two environments. Genotype, general combining ability (GCA), and specific combining ability (SCA) effects were significant for both mean disease rating and disease incidence data. The GCA effects of the parents were correlated both to mean disease ratings and to disease incidence, with the most resistant parent, CO272, having the largest negative GCA. The performance of all hybrids could not be predicted simply on the basis of the performance or GCA of the parents. Reciprocal differences for mean disease ratings were significant in one environment. Four inbreds were identified as having significant GCA for resistance to F. graminearum infection via the silk.Key words: Maize, corn, diallel, resistance, Fusarium graminearum, silk


1974 ◽  
Vol 23 (2) ◽  
pp. 207-217 ◽  
Author(s):  
Larry J. Leamy ◽  
R. W. Touchberry

A least-squares diallel analysis of the offspring of crosses of seven inbred lines of house mice was performed for the mean widths of the second (M2) and third (M3) mandibular molars. Significant differences among lines, as well as between inbreds and hybrids (positive heterosis) were found for these characters. Estimates of the heritabilities (from general combining ability variances) were high for both teeth as were estimates of maternal effects. Specific combining ability and reciprocal effects were significant only for the M3. Additionally, X-irradiation reduced the mean number of individuals per litter, and thereby indirectly influenced the widths of both molars.


1970 ◽  
Vol 12 (3) ◽  
pp. 484-489 ◽  
Author(s):  
Bronius Povilaitis

The eight tobacco cultivars Delcrest, Hicks Broadleaf, Yellow Gold and Jamaica Wrapper of the flue-cured type and Burley 1, Burley 21, Virginia B29 and Kentucky 12 of the burley type and their crosses and reciprocals were grown in an 8 × 8 diallel-cross experiment. Diallel analyses were completed according to procedures described by Hayman, Griffing and Robinson.The mean squares for general combining ability and for Hayman's a made up a considerably higher proportion of the total variability than the other subdivisions. The variances for special combining ability were in all instances smaller than those for general combining ability, although there were differences in size and in levels of significance between Griffing's and Robinson's methods. The statistic due to additive effects of genes (Hayman's D) was significant for days to flower, height, and number of leaves, and the statistic due to dominance effects significant for days to flower and height. The greatest effect in decreasing the number of days to flower was exhibited by the cultivar Delcrest, and the greatest effect in increasing the number of days to flower was by Yellow Gold and Kentucky 12. Kentucky 12 showed the greatest effect in increasing height and number of leaves.


2019 ◽  
Vol 41 ◽  
pp. e42705
Author(s):  
Rafael Heinz ◽  
Larissa Pereira Ribeiro ◽  
Manoel Carlos Gonçalves ◽  
Leonardo Lopes Bhering ◽  
Paulo Eduardo Teodoro

The objective of this work was to estimate the general combining ability of partially inbred lines under high and low nitrogen (N) conditions and to select promising lines to obtain high yields for both conditions. Fifty-five partially inbred S1 progenies were evaluated using the top-cross method, where the lines were crossed with two testers. The 110 top-cross hybrids were evaluated for grain yield during the off-season of 2012 at two sites in the Brazilian Midwest. Partial diallel analysis was performed with the adjusted means of each of the individual analyses of the top crosses. The combining ability of partially inbred lines and testers as well as their interaction with N levels, was estimated for each site. The coefficient of concordance among 15 partially inbred lines selected by the highest general combining ability estimates for each N level was 0.60. The S1 lines 39, 11, 41, 55, 38, 37, 6, 8, and 14 were selected at both N levels. This indicates that these lines can be used to identify ideal hybrids for growing in the off-season in the Brazilian Midwest.


1981 ◽  
Vol 23 (4) ◽  
pp. 585-590
Author(s):  
I. S. Ogilvie ◽  
V. Kozumplik

A diallel cross of four cigar and one pipe tobacco (Nicotiana tabacum L.) was analyzed for the following characters in samples of cured tobacco: (1) percentage of light filler; (2) percentage of heavy filler; (3) percentage of top filler; (4) percentage of bottom filler; (5) percentage of total filler; (6) percentage of marketable trash and (7) total percentage of marketable tobacco. The experiment was performed over three years with four replications. Analysis was done for general combining ability and specific combining ability. General combining ability was greater than specific combining ability for all parameters, although specific combining ability effects were also present for all parameters with the exception of total marketable tobacco. Reciprocal effects were completely absent. The line Pennbel 69 showed a negative general combining ability effect for all grades of filler, total filler and total marketable tobacco with a positive effect for percentage of marketable trash. High positive specific combining ability effects for percentage total filler and high negative specific combining ability effects for percentage marketable trash were shown by crosses of Pennbel 69 with the other four cultivars.


1991 ◽  
Vol 116 (2) ◽  
pp. 330-335 ◽  
Author(s):  
Timothy Laverty ◽  
N. Vorsa

Vaccinium ashei (6x) /V. corymbosum (4x) pentaploid hybrids backcrossed to V. ashei yield aneuploid progeny ranging in chromosome number from 5x to 6x levels. Six backcross aneuploids having chromosome numbers of 2n = 61, 62, 64, 66, 68, and 70 were selected from this backcross and crossed in a complete diallel mating design and backcrossed (as female parents) to two V. ashei cultivars and an interspecific hexaploid hybrid. Fertility variables measured were percent fruit set, total seed per berry, developed seed per berry, percent developed seed per berry, percent seed germination, developed seed per pollination, and seedlings per pollination. A significant linear and positive relationship was found between chromosome number and all seven fertility variables. However, regression accounted for 30% or less of the variation among crosses. Diallel analysis revealed that general combining ability was the major contributing effect for all seven variables, followed by reciprocal effects. Specific combining ability was not significant. The second backcross to the hexaploid level suggested significant effects due to both the BC1 aneuploid and hexaploid genotypes and to a significant genotype × genotype interaction for three of the variables. All six aneuploids were either fully or partially self-sterile. The findings of this study substantiate earlier suggestions that pentaploids in blueberry can be used to facilitate bilateral transfer of characteristics between the tetraploid and hexaploid levels in blueberry.


1974 ◽  
Vol 10 (4) ◽  
pp. 241-245 ◽  
Author(s):  
K. P. Sinolinding ◽  
A. Rehman Chowdhry

SUMMARYAnalysis of a 4-parent diallel cross showed marked heterosis for yield and its components in two crosses (Mexipak × Dirk and C273 × AU49) under irrigation, while little or negative heterosis occurred under moisture stress. A large part of the genetic variation among crosses for yield, and most components of yield, was attributed to the general combining ability, indicating that the additive effects were important. Reciprocal effects and various interactions were insignificant except for kernel weight, which suggests that effective selection could be made under irrigation of genotypes adaptable to moisture stress.


1972 ◽  
Vol 52 (4) ◽  
pp. 545-550
Author(s):  
P. J. LOESCH Jr. ◽  
M. S. ZUBER

We evaluated 66 inter se crosses among 12 inbred lines of maize in 2 years at two locations. The inheritance of ash content of the stalk was determined by means of diallel analysis. Significant differences in ash content among the 66 F1 hybrids were obtained. General combining ability (GCA) and specific combining ability (SCA) mean squares were also statistically significant. The additive genetic variation was much larger than the nonadditive variation. Interactions of GCA and SCA with locations and with years × locations were significant. The broad sense heritability estimate for ash content of stalk was.62. The primary objective, to determine whether ash content of the stalk is positively associated with susceptibility to stalk lodging, was only partially supported. The genotypic correlation between ash content of stalk lodging was relatively low (+.280) and of little predictive value.


Genetics ◽  
1975 ◽  
Vol 81 (2) ◽  
pp. 369-376
Author(s):  
M G Jamison ◽  
J M White ◽  
W E Vinson ◽  
K Hinkelmann

ABSTRACT Two replications of a complete diallel cross experiment were performed among four partially inbred lines of mice. These inbred lines originated from a random-bred ICR strain and were produced by 12 generations of full sibbing (F ≃ 92%). Individual body weight was recorded for each animal at 12, 21, 42 and 56 days of age. Body weight gain traits were examined for intervals 12-21, 21-42 and 42-56 days. Simultaneous least squares analyses of inbred and linecrossed groups were used. Sex differences were highly significant for all traits. Replicate differences were significant but made a small contribution to the total variation. Inbred lines differed greatly. Crosses showed growth trends similar to their contemporary maternal and paternal inbreds. Heterosis was highly significant for all traits except 21-day weight. Inbreds were heavier at 12 days of age, but linecrossed progeny were superior to inbreds for all post-weaning weights. General combining ability was highly significant for 12- and 56-day weights and 21-42-day gain. Specific combining ability was highly significant for 21-day weight, 12-21- and 42-56-day gain. Significant maternal effects were found for all individual weights but not for 12-21- and 21-42-day gain. Residual reciprocal effects were significant for all traits. Estimated variances among linecrossed groups contained a large maternal component, a fluctuating additive genetic component and consistent non-additive genetic influence on all growth parameters measured.


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