Heterosis and Combining Ability in Wheat under Irrigation and Moisture Stress

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.

1979 ◽  
Vol 21 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Wai-Koon Tan ◽  
Geok-Yong Tan ◽  
P. D. Walton

Twenty-one progenies and the parents of a 7 × 7 half diallel cross of smooth bromegrass (Bromus inermis Leyss.) were evaluated at four locations in Alberta in each of two years, for genetic variation and genetic by environment interactions in the expression of their yield potentials. Years, locations and their interactions were highly significant in the combined analysis of variance. Combining ability analysis revealed that general combining ability (GCA) and specific combining ability (SCA) were both important in the expression of yield, including spring, fall and annual yield, whereas GCA was more important than SCA for yield per area. Although the genotype × environment interactions were all highly significant, variation accounted for by combining ability effects was generally higher than the interaction effects of GCA and SCA respectively, with environments. High average GCA effects for spring, fall and annual yield were demonstrated for the clones UA5, UA9 and B42. These together with the high average SCA effects suggested that the three clones could be included in a synthetic to develop high yielding cultivars. The results suggested that recurrent selections involving multi-location and multi-year testing seems necessary in breeding for high yielding bromegrass cultivars in Alberta.


1968 ◽  
Vol 10 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Lewis E. Aalders ◽  
Donald L. Craig

Seedlings of a diallel cross of seven strawberry inbreds omitting reciprocals were fruited in matted rows. Per acre fruit yields were comparable with leading cultivars, but berry appearance and quality of the hybrids were poor. Differences in resistance to powdery mildew reflected the values of the cultivars from which the inbreds were derived.All four characters studied showed significant general combining ability values, and three of the four showed significant specific combining ability values. These results are consistent with previous findings of considerable amounts of non-additive genetic variation in the strawberry.


1983 ◽  
Vol 63 (3) ◽  
pp. 497-509 ◽  
Author(s):  
J. N. B. SHRESTHA ◽  
W. E. REMPEL ◽  
W. J. BOYLAN ◽  
K. P. MILLER

Five breeds of sheep (Minnesota 100, 102, 103 and 105, and Shropshire), and their two breed crosses, including reciprocals, were raised at the University of Minnesota's Agricultural Experiment Stations, Rosemount and Waseca. Included in this study were 421 purebred and 1037 crossbred ewes and their 367 purebred and 849 Suffolk-sired crossbred lambs born over a 5-yr period. Estimates of heterosis, pure breed, general, specific, maternal and reciprocal effects were obtained for fertility, prolificacy, livability, overall reproduction, and total and average lamb weights per ewe at birth and weaning (100 days). Significant differences were observed for prolificacy, livability, and total and average lamb weights per ewe at birth and weaning. General combining ability was important (P < 0.01) for prolificacy and average lamb weight per ewe at birth and weaning. Specific combining ability was significant for prolificacy, total lamb weight per ewe at birth, and average lamb weight per ewe at weaning. Maternal and reciprocal effects were not important (P > 0.05). Significant interactions of location with specific combining ability and maternal ability were observed for average lamb weight per ewe at weaning. Breeds ranked differently on purebred performance and general combining ability. Heterosis, pure breeds, and general and specific combining ability had important effects. Therefore, both additive and non-additive effects should be considered in developing breeding strategies to maximize productivity for commercial lamb production. Key words: Sheep, breed, ewe productivity, genetic effects


2015 ◽  
Vol 36 (4) ◽  
Author(s):  
K. John ◽  
P. Raghava Reddy

Hybridization followed by selection in segregating generations is the main mode of varietal development in self-pollinated crops like groundnut. Before making crosses, it is important to know which of the parents are going to nick well and yield desirable segregants in terms of yield and other desirable attributes aimed at. There are different mating designs to identify the parents to be included in hybridization programmes. One of the widely used and most informative one is diallel mating design. After identification of parents more suitable to be involved in breeding programme, it is necessary to know the mode of inheritance of the traits to be improved to make wise choice of selection approaches to be followed in segregating generations. Therefore the breeder is constantly needing to determine the potential of additional germplasm as parents, Earlier studies suggest the importance of additive general combining ability (GCA) and non additive (specific combining ability and heterosis) genetic effects in evaluating hybrid performance among parental groundnut lines. The prominent effects on crop plants are reduction in plant growth and changes in various physiological processes. Moisture stress can also adversely influence yield attributes like number of mature pods per plant, 100-pod weight, 100-kernel weight, shelling per cent and harvest index.


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.


2021 ◽  
Vol 17 (3) ◽  
pp. 183-192
Author(s):  
V. M. Hudzenko ◽  
T. P. Polishchuk ◽  
A. A. Lysenko ◽  
L. V. Khudolii ◽  
A. I. Babenko

Purpose. To reveal the breeding and genetic peculiarities for spring barley 1000 kernel weight and to identify genetic sources for breeding under conditions of the central part of the Forest-Steppe of Ukraine. Methods. Investigations were carried out at the V. M. Remeslo Myronivka Institute of Wheat of the NAAS of Ukraine. Spring barley F1 of two comp­lete (6 ´ 6) diallel crossing schemes was investigated. The first scheme included modern both domestic and foreign spring barley malting varieties (‘MIP Tytul’, ‘Avhur’, ‘Datcha’, ‘Quench’, ‘Gladys’, ‘Beatrix’), the second – classic covered awned (‘MIP Myroslav’, ‘Sebastian’), awnless (‘Kozyr’, ‘Vitrazh’) and naked (‘Condor’, ‘CDC Rattan’) varieties. Results. Various types of inheritance of 1000 kernel weight were revealed, with the exception of negative dominance. The proportion of combinations with corresponding values ​​of the degree of phenotypic dominance varied depending on the genotypes involved in the crossing and the years of testing. In both crossing schemes, both in 2019 and in 2020, positive overdominance was found in most combinations. The grea­test number of combinations with the manifestation of hete­rosis under different growing conditions was noted when varieties ‘Gladys’ and ‘MIP Myroslav’ were used in crossing. According to the parameters of genetic variation, it was revealed that the trait was determined mainly by the additive-dominant system. The dominance was aimed at increasing the 1000 kernel weight. Only in the second crossing scheme in 2019 the value of the directional dominance indicator was unreliable. In the loci, incomplete dominance in 2019 and over-dominance in 2020 were revealed. Reliably high effects of the general combining ability in both years were noted for varieties ‘Datcha’, ‘Gladys’, ‘MIP Myroslav’, ‘Kozyr’ and ‘Vitrazh’. Conclusions. The revealed breeding and genetic peculiarities indicate that for the overwhelming majority of created hybrid combinations will be required the final selection in later generations, when the dominant alleles are homozygous. Spring barley awned varieties ‘Gladys’, ‘MIP Myroslav’ and ‘Datcha’, as well as awnless varieties ‘Kozyr’ and ‘Vitrage’ can be used as effective genetic sources for increa­sing the 1000 kernel weight


1971 ◽  
Vol 22 (3) ◽  
pp. 359 ◽  
Author(s):  
GM Bhatt

Levels of hybrid vigour for earliness, plant height, four components of yield, and yield were examined in the F1 generation of a diallel cross of eight cultivars of spring wheat. Kernel weight and kernels per spike exhibited high levels of heterosis effects. The analysis for general combining ability indicated that a large part of the total genetic variation observed for six out of seven traits was associated with genes which were additive in their effects. The estimates for specific combining ability were highly significant for five out of seven traits. These estimates were lower than those of general combining ability for six out of seven traits. The combining ability analysis helped in classifying the parents in terms of their hybrid performance and in gaining greater understanding of the nature of quantitatively inherited traits. The importance of genetic diversity in relation to heterosis was also assessed.


1976 ◽  
Vol 56 (2) ◽  
pp. 263-274 ◽  
Author(s):  
D. R. SAMPSON

Twenty-eight oat hybrids from a diallel cross of eight parents were evaluated using field-grown F2 (1970) and F3 (1971) bulks at competitive spacing and with different exposures to moisture stress. These were compared with irrigated, space-planted F1’s. Short, stout straw was negatively correlated with grain yield. Correlations of 1,000-kernel weight and panicle number with other traits changed sharply from year to year. General combining ability (GCA) effects showed that Astro, Clintford and Purdue 6316 were outstanding parents for desirable stem type, as were Gemini and Clintford for 1,000-kernel weight and Gemini, Kelsey and Marino for yield. Index selection among the progenies using four traits gave largely contradictory results for the 2 yr, but GCA effects of the index values point to Astro and Clintford as the best all-round parents. Data from F1 spaced plants in an optimum environment were useful for predicting field responses in the year when no moisture stress occurred during grain filling, but not in the year with such stress. Midparent values for grain yield were highly correlated with progenies’ yields only in the year with no moisture stress during grain filling.


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.


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.


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