scholarly journals Stem breakage and forking in low and high elevation Pinus tecunumanii

2011 ◽  
Vol 60 (1-6) ◽  
pp. 1-8
Author(s):  
B. I. Nyoka ◽  
P. Tongoona ◽  
C. M. Gumbie
Keyword(s):  
Test Site ◽  
High Elevation ◽  
Seed Source ◽  
Environment Interaction ◽  
Source Selection ◽  
Genotype Environment Interaction ◽  
Stem Breakage ◽  
Pinus Tecunumanii ◽  
The Mean

Summary The incidences of stem breakage and forking at ages five and eight years in low and high elevation Pinus tecunumanii were assessed in multilocation provenance-progeny tests comprising 16 provenances of both low and high elevation P. tecunumanii. Stem breakage and forking were found to be more severe at the highest test site (1760m a.s.l.), and progressively declined with decreasing altitude. The mean stem breakage at individual sites for the two ages ranged from 0.7% to 19.5% in the low elevation P. tecunumanii, while that of the high elevation P. tecunumanii was between 0% and 12.9%. The mean percent of forked trees ranged between 3.9% and 46.8% in the low elevation P. tecunumanii and from 5.3% to 27.5% in the high elevation P. tecunumanii. The wide provenance variation in stem breakage and forking suggests that genetic factors related to seed source influence these traits. The low elevation P. tecunumanii had significantly higher incidences of stem breakage and forked trees compared to the high elevation P. tecunumanii. Overall, provenances with very low levels of stem breakage and forking included San Jerónimo, Montana Sumpul, Las Piedrecitas and Jocón. Although tested on a limited number of sites, the genotype* environment interaction at both provenance and family level appeared to be inconsequential. The mean percent of trees with stem breakage and forks increased between the two assessment ages, with changes ranging from small to more than double, implying that decision on selection against stem breakage and forking should be avoided at five years or earlier. The results of this study showed that the challenges of stem breakage and forking in plantations can be managed by one or a combination of site and seed source selection, while intensive breeding and selection could also be used as a long term strategy.

scholarly journals Multiattribute Response of Maize Genotypes Tested in Different Coastal Regions of Brazil

2011 ◽  
Vol 2011 ◽  
pp. 1-6
Author(s):  
Lúcio Borges de Araújo ◽  
Mario Varela Nualles ◽  
Mirian Fernandes Carvalho Araújo ◽  
Carlos Tadeu dos Santos Dias
Keyword(s):  
Principal Components ◽  
Environment Interaction ◽  
Coastal Regions ◽  
Multivariate Response ◽  
Genotype Environment Interaction ◽  
Maize Genotypes ◽  
The Mean ◽  
Components Analysis ◽  
And Performance ◽  
Main Effects

This work applies the three mode principal components analysis to analyze simultaneously the multiple attributes; to fit of models with additive main effects and multiplicative interaction effects (AMMI models) and the regressions models on sites (SREG models); to evaluate, respectively, the multivariate response of the genotype × environment interaction and the mean response of 36 genotypes of corn tested in 4 locations in Brazil. The results were presented by joint plots to identify the best genotypes for their adaptability and performance in the set of attributes.

GENOTYPE-ENVIRONMENT INTERACTION VARIANCES IN YIELD TRIALS OF FALL RYE

1970 ◽  
Vol 50 (1) ◽  
pp. 77-80 ◽  
Author(s):  
P. J. KALTSIKES
Keyword(s):  
Genotype By Environment Interaction ◽  
Western Canada ◽  
Environment Interaction ◽  
First Order ◽  
Genotype By Environment ◽  
Genotype Environment Interaction ◽  
Yield Difference ◽  
The Mean ◽  
Yield Trials ◽  
Interaction Variance

Estimates of genotype by environment interaction variances were obtained from the western Canada Co-operative fall rye tests grown in 1963–1967. All first-order interactions and the second-order interactions were significantly greater than zero at the 0.05 level of probability. Although the estimate of cultivar by year interaction variance was relatively small, it accounted for 40% of the variance of a cultivar mean when only three years of testing were considered. However, testing in 20 locations for three years with four replicates could detect yield differences of approximately 10% of the mean of the highest yielding cultivar. If further reduction of the yield difference detectable is desired, more locations should be included in the test.

Yield Stability of Different Elite Wheat Lines under Drought and Irrigated Environments using AMMI and GGE Biplots

2021 ◽  
Vol 9 (2) ◽  
pp. 98-106
Author(s):  
Dipendra Regmi ◽  
Mukti Ram Poudel ◽  
Bishwas K.C. ◽  
Padam Bahadur Poudel
Keyword(s):  
Principal Component ◽  
Environment Interaction ◽  
Lattice Design ◽  
Genotype Environment Interaction ◽  
Stability Model ◽  
Winter Crop ◽  
Ideal Line ◽  
Genotype Evaluation ◽  
The Mean ◽  
Wheat Lines

Wheat is the principal winter crop in Nepal. Drought affects 44% of the lands of the total wheat area in the country with a yield loss of 15–20%. This research focuses to minimize this loss through the identification of high-yielding lines stable across the drought stress and irrigated environments. The experiment was conducted in Alpha Lattice Design with 20 genotypes replicated twice with five blocks per replication from November 2019 to April 2020. The findings showed that genotypes, environments, and genotype-environment interaction have a highly significant effect on grain yield and explained 28.95%, 52.57%, and 18.47% of variation on yield, respectively. The which-won-where model revealed elite line NL 1420 is the most responsive line in the drought environment, followed by BL 4407, while elite line NL 1179 is the most stable line in irrigated environment. The mean vs stability model with principal component 1 and 2 explaining 65.76% and 34.24% respectively, showed that elite line NL 1420, BL 4407, BL 4919, Bhrikuti are both high yielding and stable lines while line NL 1179, Gautam, and NL 1384 are less stable in both test environments. Similarly, the ranking genotypes model indicated lines close to the ideal line are NL 1420, BL 4407, BL 4919, Bhrikuti as the most representative line for genotype evaluation. Thus, elite wheat line NL 1420 and NL 1179 are recommended as specifically adapted to drought and irrigated environments, respectively, and elite line NL 1420, BL 4407, BL 4919, Bhrikuti are recommended for further evaluation for stability. Int. J. Appl. Sci. Biotechnol. Vol 9(2): 98-106

scholarly journals Genotype × environment interaction in Tribolium castaneum

1964 ◽  
Vol 5 (3) ◽  
pp. 335-340 ◽  
Author(s):  
J. F. Kidwell ◽  
A. E. Freeman ◽  
L. H. Haverland ◽  
G. M. H. Rolfes
Keyword(s):  
Relative Humidity ◽  
Tribolium Castaneum ◽  
Total Variance ◽  
Direct Selection ◽  
Environment Interaction ◽  
Breeding Values ◽  
Genotype Environment Interaction ◽  
The Mean ◽  
Selection For ◽  
C 30

An experiment was conducted with the flour beetle, Tribolium castaneum to investigate genotype-environment interaction. Ninety-two matings of one male and three females were made at random from a large panmictic population. The females were transferred to individual containers after 4 days. Six daughters were randomly selected from each sire–dam pair and individually mated to unrelated males. Three of the six were placed in an incubator (33·3°C., 45% relative humidity) and three in a cabinet at room conditions (22·2–26·7°C., 30–35% relative humidity) and allowed to produce eggs during a 3-day period. Progeny were counted as pupae and larvae. The traits studied were number of pupae and number of pupae plus number of larvae. A transformation to (X +1)½ was required. A conventional least-squares model was employed, and a large environmental effect was observed. In the incubator the mean number of pupae was 13·4 and of pupae + larvae was 20·1 while the corresponding figures for room conditions were 3·3 and 9·2. Genotype-environment interaction accounted for 3·7 to 6·7% of the total variance for (pupae + 1)½ and 2·1 to 8·3% for (pupae + larvae+ 1)½. Heritability of the traits was essentially the same in both environments. The interaction was due to an increasing difference between environments in production associated with increasing breeding values of the sire, and to small changes in rank of breeding values on the two environments. As a result of the interaction, selection in one environment for production on the other would be expected to be only 71 to 72% as effective as direct selection for (pupae + 1)½ and 62 to 86% for (pupae + larvae + 1)½ even though the fraction of the total variance attributed to genotype-environmental interaction was less than 10%.

scholarly journals l.240 ADAPTABILITY AND STABILITY OF Coffea arabica LINES IN THE WESTERN AMAZON

2019 ◽  
Vol 14 (2) ◽  
pp. 240
Author(s):  
Carolina Augusto de Souza ◽  
Alexsandro Lara Teixeira ◽  
Josemar Dávila Torres ◽  
Camila Andrade Silva ◽  
Marcelo Curitiba Espindula ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Coffea Arabica ◽  
Environment Interaction ◽  
Gge Biplot ◽  
Early Maturation ◽  
Genotype Environment Interaction ◽  
The Mean ◽  
Low Altitude ◽  
Set Up ◽  
Selection Of

Growing Coffea arabica in regions of the Western Amazon is limited by early maturation and by its limited adaptation to regions of low altitude and high temperature. The aim in this study was to quantify the genotype × environment interaction of C. arabica lines in four different environments of the Western Amazon, seeking to assist selection of new lines with greater adaptability and stability for the region. In the months of December 2012 and January 2013, four competitive trials were set up in municipalities of the states of Rondônia and Acre. Each trial was composed of 21 lines and 4 reference cultivars evaluated as controls recommended for planting in the southeast region. In combined analysis, significant differences were not detected between the cultivars and controls; the mean yield of hulled coffee was 12.05 bags ha-1. The Alta Floresta Do Oeste environment has higher yield and is the only environment favorable for growing C. arabica; that environment is differentiated from the others through its higher altitudes and low temperatures. Through GGE biplot analyses, lines 12 and 13, identified as H514-7-10-6-9 and H514-7-10-6-2-3-9, were found to have results superior to the controls in the municipality of Alta Floresta Do Oeste, RO. The gain from selection of 56% obtained from line G12 and the gain of 46% obtained from line G13 show performance superior to the best control. The germplasm studied does not have genetic variability that contributes to selection of plants for adaptation to the low altitude and high temperatures in the amazonic region.

Resource allocation in Maritime cereal cultivar trials

1994 ◽  
Vol 74 (3) ◽  
pp. 501-505
Author(s):  
G. N. Atlin ◽  
K. B. McRae
Keyword(s):  
Variance Components ◽  
Selection Response ◽  
Testing System ◽  
Environment Interaction ◽  
Acceptance Probability ◽  
Genotype Environment Interaction ◽  
The Mean ◽  
Single Standard ◽  
Variance Component Estimates ◽  
The Impact

Research funding for cooperators in the cereal cultivar testing system in Canada is declining, and cooperators are under pressure to reduce their testing effort. The impact of reducing the number of years, test sites, and replications on the standard error of cultivar means (SE), predicted response to selection (R), and the probability of accepting inferior cultivars in Maritime spring cereal registration trials was examined using variance component estimates. Reducing the number of replications increased SE less than reducing the number of sites or years of testing. Reducing replicates per site from four to two increased SE by no more than 0.02 t ha−1 when the number of sites was three or more. Reducing the number of trial sites from five to three, however, increased SE by up to 0.06 t ha−1 and reduced R by as much as 16%. The probability that a cultivar with a true yield 5% less than that of a standard would equal or exceed the standard in a 3-yr series of trials conducted at five sites ranged from 6% in 2-row barley to 21% in winter wheat. Cost reductions in the Maritime cereal registration trials should be achieved, where possible, by reducing within-site replication rather than reducing the number of trial sites. Some reduction in the risk of registering inferior cultivars can be achieved by comparing test cultivars with the mean of several standards, rather than with a single standard. Key words: Replication, genotype × environment interaction, selection response, acceptance probability, variance components, residual maximum likelihood

Simultaneous selection of yield and yield stability in chickpea genotypes using the GGE biplot technique

2013 ◽  
Vol 61 (3) ◽  
pp. 185-194 ◽  
Author(s):  
E. Farshadfar
Keyword(s):  
Grain Yield ◽  
Principal Component ◽  
Environment Interaction ◽  
Gge Biplot ◽  
Yield Data ◽  
Genotype By Environment ◽  
Growing Seasons ◽  
Genotype Environment Interaction ◽  
The Mean ◽  
Selection Of

GGE biplot analysis is an effective method, based on principal component analysis (PCA), to fully explore multi-environment trials (METs). It allows visual examination of the relationships among the test environments, genotypes and the genotype-by-environment interactions (G×E interaction). The objective of this study was to explore the effect of genotype (G) and the genotype × environment interaction (GEI) on the grain yield of 20 chickpea genotypes under two different rainfed and irrigated environments for 4 consecutive growing seasons (2008–2011). The yield data were analysed using the GGE biplot method. The first mega-environment contained environments E1, E3, E4 and E6, with genotype G17 (X96TH41K4) being the winner; the second mega-environment contained environments E5, E7 and E8, with genotype G12 (X96TH46) being the winner. The E2 environment made up another mega-environment, with G19 (FLIP-82-115) the winner. The mean performance and stability of the genotypes indicated that genotypes G4, G16 and G20 were highly stable with high grain yield.

Genetic parameters and provenenance variation of Pinus caribaea var. hondurensis in 48 international trials

2001 ◽  
Vol 31 (3) ◽  
pp. 496-511 ◽  
Author(s):  
G R Hodge ◽  
W S Dvorak
Keyword(s):  
First Generation ◽  
Genetic Parameters ◽  
Volume Growth ◽  
Environment Interaction ◽  
Pinus Caribaea ◽  
Genotype Environment Interaction ◽  
The Mean ◽  
Selection For ◽  
Similar Growth ◽  
Better Than

A total of 23 provenances or sources of Pinus caribaea var. hondurensis (Sénécl) Barr. et Golf. were tested in 48 provenance–progeny trials in Colombia, Brazil, and Venezuela. In Brazil and Venezuela, 8-year heights were approximately 12 m, while in Colombia, mean 8-year height was less than 8 m. The growth rates of the unimproved material correspond approximately to volumes of 14–15 m3·ha–1·year–1 of wood on sites in Brazil and Venezuela, and 4–5 m3·ha–1·year–1 in Colombia. Provenances had similar growth rankings in the different countries, with a type-B provenance correlation of 0.63. The best native provenances were Limón and Guanaja, Honduras. Improved first-generation sources from Queensland, Australia and Zululand, South Africa, were 5–12% better than the mean of the unimproved provenances, depending on country where planted. Mean single-site heritability for volume growth is approximately 0.18. Potential genetic gain for volume at 8 years from selection within provenance is around 30%. Foxtailing is also under moderate genetic control with heritability around 0.15. Genotype × environment interaction for volume growth is generally higher for tests located in different countries than in the same countries. Selection for age-8 volume using age-5 data would be 93% as effective as selection at age 8.

scholarly journals Conventional Selection versus Methods that Use Genotype × Environment Interaction in Sweet Corn Trials

HortScience ◽  
1992 ◽  
Vol 27 (5) ◽  
pp. 436-438 ◽  
Author(s):  
V.R. Bachireddy ◽  
R. Payne ◽  
K.L. Chin ◽  
M.S. Kang
Keyword(s):  
Sweet Corn ◽  
Yield Reduction ◽  
Environment Interaction ◽  
Selection Methods ◽  
Environmental Index ◽  
Data Set ◽  
Linear Effect ◽  
Genotype Environment Interaction ◽  
Stable Performance ◽  
The Mean

The analysis of variance of a data set made up of 30 sweet corn (Zea mays L.) hybrids evaluated over 5 years for marketable ears (dozens per hectare) indicated a significant genotype (hybrid) × year (GY) interaction. Three selection methods were compared: 1) a conventional method based on mean yield alone (YA), 2) Kang's ranksum (KRS) method, and 3) Kang's modified rank-sum (KMR) method. The number of hybrids selected on the basis of YA, KRS, and KMR was 13. The KRS selected the lowest number of unstable hybrids (three) compared with the YA and KMR, which selected eight and six unstable hybrids, respectively. The mean yields of the selected hybrids were 3034 dozen/ha for YA, 2945 dozen/ha for KRS, and 3019 dozen/ha for KMR. The mean yield of KRS-selected hybrids and KMR-selected hybrids was <2.9% and 0.5%, respectively, than that of YA-based selections. This yield reduction was regarded as insignificant considering the farmer would be able to choose more consistently performing hybrids on the basis of KRS than on the basis of KMR or YA. Heterogeneity due to environmental index is the mean of all genotypes in the jth year and X is the overall mean) was significant and was removed from the GY interaction. The removal of heterogeneity revealed that hybrids 77-2269, 116-Kandy Korn-EH, Golden Queen, 141-Sundance, Merit, and Stowell Evergreen were unstable because of a linear effect of the environmental index, and that hybrids 76-2681 and 806F-Truckers showed stable performance due to a linear effect of the environmental index.

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