scholarly journals Yield Stability of Contrasting Orchardgrass (Dactylis Glomerata L.) Genotypes Over the Years and Water Regimes 

2021 ◽  
Author(s):  
Fatemeh Saeidnia ◽  
Mohammad Mahdi Majidi ◽  
Aghafakhr Mirlohi ◽  
Mohammad Reza Dehghani ◽  
Behnam Hosseini
Keyword(s):  
Water Deficit ◽  
Combining Ability ◽  
Genotypic Variation ◽  
Forage Yield ◽  
Environment Interaction ◽  
Genetic Progress ◽  
Narrow Sense Heritability ◽  
Sib Families ◽  
Dactylis Glomerata L ◽  
The Stability

Abstract Stability of combining ability and the nature and extent of genetic and genotype×environment interaction is poorly understood in orchardgrass especially under climate change conditions. In the present study, first-generation half-sib families of orchardgrass derived from the polycross of 25 parental genotypes were evaluated in the field during five years under two irrigation regimes of normal and water deficit. Considerable genotypic variation was observed among half-sib families for all of the evaluated traits, demonstrating high potential for improving these traits through half-sib mating. The effects of water deficit on dry forage yield increased from the first to fifth year and consequently declined the persistence of half-sib families. Results showed that both genetic and non-genetic gene actions played a role in the control of dry forage yield; indicating that selection based on an index would be more useful to attain genetic progress. Moreover, the estimates of narrow-sense heritability for most of the traits were higher under deficit irrigation, which is advantageous for successful selection. The stability of general combining ability, plant productivity, and drought tolerance clearly identified G4, G5, G6, and G14 as the superior and stable parental genotypes able to transmit both stability and forage productivity to their progenies.

scholarly journals Genotype x Environment Interaction in Maritime Pine Families in Galicia, Northwest Spain

2004 ◽  
Vol 53 (1-6) ◽  
pp. 175-182 ◽  
Author(s):  
R. Zas ◽  
E. Merlo ◽  
J. Fernández-López
Keyword(s):  
Variance Component ◽  
Practical Importance ◽  
Genetic Correlations ◽  
Maritime Pine ◽  
Environment Interaction ◽  
Nw Spain ◽  
Genotype X Environment ◽  
Pinus Pinaster Ait ◽  
Sib Families ◽  
The Stability

SummaryThe magnitude and practical importance of family x site interactions for growth and form traits in maritime pine (Pinus pinaster Ait.) breeding in the coastal area of Galicia (NW Spain) were analysed using several different techniques. Data were from 58 8-yr-old half-sib families planted across four sites. The analysis of variance and the ratio of interaction to family variance component showed the interactions to be quantitatively important for several traits, especially for volume and straightness. Genetic correlations between the same trait at different sites were moderate and highly variable, especially for certain pairs of sites. The results indicated that interactions are a consequence of few highly interactive families that may be particularly sensitive to environmental variation. The removal of these families from the breeding program appeared as an effective strategy to solve the interactions. Results are discussed in relation to the stability parameter considered to identify the most unstable progenies.

Genetics of post-drought recovery, persistence and summer dormancy in orchardgrass (Dactylis glomerata)

2018 ◽  
Vol 69 (11) ◽  
pp. 1140
Author(s):  
Fatemeh Pirnajmedin ◽  
Mohammad Mahdi Majidi ◽  
Fatemeh Saeidnia ◽  
Behnam Hoseini ◽  
Aghafakhr Mirlohi ◽  
...  
Keyword(s):  
Yield Components ◽  
Deficit Irrigation ◽  
Dactylis Glomerata ◽  
Phenotypic Selection ◽  
Forage Yield ◽  
Genetic Progress ◽  
Narrow Sense Heritability ◽  
Regulated Deficit Irrigation ◽  
Summer Dormancy ◽  
Drought Recovery

The genetic basis of post-drought recovery, summer dormancy and persistence under drought stress is little investigated in orchardgrass (Dactylis glomerata L.). In this study, polycross populations (half-sib genotypes) were evaluated under normal and regulated deficit irrigation for 3 years (2012–14) in the field. Irrigation was then withheld in 2015, and the genotypes were evaluated for post-drought recovery and persistence. The results showed that regulated deficit irrigation decreased forage yield, yield components, persistence and recovery. A broad range of general combining ability was observed for most of the measured traits. Moderate to high estimation of narrow-sense heritability for yield components, persistence, recovery and summer dormancy index indicated that phenotypic selection may be successful to attain genetic progress. Under deficit irrigation, flowering time was positively correlated with persistence and recovery, indicating that selection based on lateness would lead to improvement in these traits. Stable and superior families across environments were identified based on regression coefficients and principle component analysis that would be desirable in future breeding programs.

Genetic progress from 40 years of orchardgrass breeding in North America measured under management-intensive rotational grazing

2001 ◽  
Vol 81 (4) ◽  
pp. 713-721 ◽  
Author(s):  
M. D. Casler ◽  
S. L. Fales ◽  
D. J. Undersander ◽  
A. R. McElroy
Keyword(s):  
North America ◽  
North American ◽  
Dactylis Glomerata ◽  
Grazing Pressure ◽  
Forage Yield ◽  
Rotational Grazing ◽  
Genetic Progress ◽  
State College ◽  
The North ◽  
Dactylis Glomerata L

There has been considerable activity in breeding orchardgrass (Dactylis glomerata L.) cultivars in North America during the latter half of the 20th century. The objective of this study was to determine if genetic improvements in the North American orchardgrass germplasm pool have been realized or can be detected under management intensive grazing. Forty-three orchardgrass cultivars, in three maturity groups, representing adapted North American germplasm and potentially unadapted European germplasm, were evaluated under management-intensive rotational grazing at two locations in the northern USA. Cultivar means varied for apparent preference and this variation was largely due to herbage availability at State College, PA, where grazing pressure was relatively high, but to other factors at Arlington, WI, where grazing pressure was relatively low. North American cultivars tended to have higher net herbage accumulation than European cultivars, corresponding well to differences in forage yield of hay plots. Orchardgrass cultivars that were significantly higher in hay yield than their predecessors showed mixed results with respect to net herbage accumulation under grazing: some increases, some decreases, and some with no change. These results indicate that an individual orchardgrass cultivar can be well adapted to both management systems, only one of the two systems, or neither system. Genetic increases in net herbage accumulation may occur serendipitously, but directed selection for specific traits that confer productivity under grazing, or net herbage accumulation per se, will probably ensure a higher probability of success for an orchardgrass breeding program directed to pastures. Key words: Dactylis glomerata, cultivar evaluation, breeding, selection, grazing

Genetic variation for wheat spike fertility in cultivars and early breeding materials

2015 ◽  
Vol 154 (1) ◽  
pp. 13-22 ◽  
Author(s):  
N. E. MIRABELLA ◽  
P. E. ABBATE ◽  
I. A. RAMIREZ ◽  
A. C. PONTAROLI
Keyword(s):  
Grain Yield ◽  
Genotypic Variation ◽  
Selection Criterion ◽  
Dry Weight ◽  
Wheat Breeding ◽  
Environment Interaction ◽  
Grain Number ◽  
Narrow Sense Heritability ◽  
Frequency Distributions ◽  
Commercial Cultivars

SUMMARYGrain yield in bread wheat is often tightly associated with grain number/m2. In turn, spike fertility (SF), i.e., the quotient between grain number and spike chaff dry weight, accounts for a great proportion of the variation in grain number among cultivars. In order to examine the potential use of SF as a breeding target, (1) variation for the trait was assessed in six datasets combining commercial cultivars under different environmental conditions, (2) trait heritability was estimated in a set of F1 hybrids derived from controlled crosses between cultivars with contrasting SF and (3) SF distribution pattern was analysed in two F2 segregating populations. Analysis of commercial cultivars revealed considerable variation for SF, under both optimal and sub-optimal conditions. In addition, genotypic variation was consistently larger than genotype × environment interaction variation in all datasets. Narrow sense heritability, estimated by the mid-parent-offspring regression of 20 F1 hybrids and their respective parents, was 0·63. Data from two F2 populations exhibited bell-shaped and symmetric frequency distributions of SF, with a SF mean intermediate between the parental values. Substantial transgressive segregation was detected in both F2 populations. In conclusion, SF appears to be a heritable trait with predominantly additive effects. This warrants further investigation on the feasibility of using SF as an early selection criterion in wheat breeding programs aimed at increasing grain yield.

scholarly journals Stability of combining ability effects in maize hybrids

2009 ◽  
Vol 66 (4) ◽  
pp. 494-498 ◽  
Author(s):  
Juarez Campolina Machado ◽  
João Cândido de Souza ◽  
Magno Antonio Patto Ramalho ◽  
José Luís Lima
Keyword(s):  
Combining Ability ◽  
Block Design ◽  
Diallel Analysis ◽  
Genotype By Environment Interaction ◽  
Specific Combining Ability ◽  
Environment Interaction ◽  
Additive Effects ◽  
Maize Hybrids ◽  
Genotype By Environment ◽  
The Stability

General and specific combining ability effects are important indicators in a maize (Zea mays L.) breeding program aiming hybrid development. The objectives of the present study were to estimate the general (GCA) and specific combining abilities (SCA) effects of commercial maize hybrids using a complete diallel scheme and to assess the stabilities of these estimates. Fifty-five entries were assessed; ten commercial single-crosses and all possible double-crosses. The experiments were carried out in 12 environments in the 2005/06 growing season. A randomized complete block design was used with three replications per environment. Ear yield was evaluated, corrected to 13% of moisture content. The combined diallel analysis involving all environments was performed and the stability of general and specific combining ability effects was investigated. The underlying nonparametric statistics evaluated the contribution of each effect to the genotype by environment interaction. Non-additive effects were more important for this set of hybrids than the additive effects. It was possible to select parents with high stability for combining ability and with high GCA.

scholarly journals Inheritance of Summer Dormancy, Persistence and Productivity Using Half-sib Matting in Tall Fescue 

2020 ◽  
Author(s):  
Fatemeh Pirnajmedin ◽  
Mohammad Mahdi Majidi ◽  
Mohammad Hadi Taleb ◽  
Sayed Ali Mohammad Mirmohammady Maibody
Keyword(s):  
Tall Fescue ◽  
Recurrent Selection ◽  
Gene Action ◽  
Genotypic Variation ◽  
Dominant Gene ◽  
Narrow Sense ◽  
Forage Production ◽  
Narrow Sense Heritability ◽  
Summer Dormancy ◽  
Sib Families

Abstract Background: The genetic basis and variability of persistence and summer dormancy and their association with forage production traits has been less investigated in tall fescue. Results: High genotypic variation was found for all the measured traits in both parental genotypes and half-sib families. Incomplete summer dormancy was found for most of the evaluated genotypes. Summer dormancy index were negatively correlated with forage production and yield related traits. Half-sib families had higher persistence than parental genotypes, which can be due to the heterosis expression in progenies. Moderate narrow-sense heritability for persistence indicates that both additive and dominant gene action may play a role in the expression of this trait. Yield-related traits and summer dormancy showed moderate to high estimates of narrow sense heritability (0.63-0.73) indicates additive gene action for these traits. This suggest phenotypic recurrent selection can be successful to achieve genetic progress. Conclusion: In conclusion, our results can enhance the knowledge of inheritance of summer dormancy and related traits which would be useful for future genetic studies. Based on the general combining ability and application of multivariate analysis, preferable genotypes for forage use (such as 21M and 1E) and turf application (such as 17M and 4E) were identified for future programs.

Combining Ability of Plant Height and Yield components in Indian Mustard (Brassica junceaL.Czern & Coss.) under Salt affected Soil using Line×Tester Analysis

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
SHAILESH CHAND GAUTAM ◽  
MP Chauhan
Keyword(s):  
Plant Height ◽  
Seed Yield ◽  
Combining Ability ◽  
Yield Components ◽  
Indian Mustard ◽  
Heritability Estimate ◽  
Genetic Effects ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Additive Genetic Effects

Line × tester analysis of twenty lines and three testers of Indian mustard (Brassica juncea L. Czern & Coss.) cultivars were used to estimate general combining ability (GCA), specific combining ability (SCA) effects, high parent heterosis and narrow-sense heritability estimate for plant height, yield components and seed yield. Significant variance of line x tester for the traits like pods per plant and seed yield indicating non additive genetic effects have important role for controlling these traits. Significant mean squares of parents v/s crosses which are indicating significant average heterosis were also significant for all the traits except seeds per pod. High narrow-sense heritability estimates for all the traits except seeds per pod exhibited the prime importance of additive genetic effects for these traits except seeds per pod. Most of the crosses with negative SCA effect for plant height had at least one parent with significant negative or negative GCA effect for this trait. For most of the traits except pods per plant, the efficiency of high parent heterosis effect was more than SCA effect for determining superior cross combinations.

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