Estimation of genotype x environment interaction for yield in green beans (Phaseolus vulgaris)

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Date
2000-11
Authors
Pillay, Kirubashin Nadarajh
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Publisher
University of the Free State
Abstract
English: 1. The objective of this study was to establish the significance of GxE interaction on yield in snap beans, secondly to determine and compare the appropriate analytical method to describe the GxE interaction. Thirdly, to determine the optimal number of locations, years and replications required for efficient testing. 2. Nine snap bean varieties were included in trials at four locations, with the trials being repeated over three years (1998-2000).The pod yield was measured. The data was analysed applying the ANOVA, Finlay and Wilkinson, and the AMMI models. Variance components were also calculated to determine the influence of the different effects on the theoretical variance of the mean thus allowing for the optimal allocation of locations, years and replications. 3. The GxL, GxY and GxYxL interactions were significant for pod yield. The estimated variance components for yield shows that 02g, 0291' 02gy and 029lY contribute 23.5, 18.8, 4.9 and 34.8 percent respectively to the total phenotypic variance. The contribution of the error variance in these trials was 18.0 percent. 4. According to Finlay and Wilkinson, genotypes G3, G5 and G9 were classified as having average stability and high yields therefore good adaptability. Genotype G8 has above average stability while G1, G2, G4, G6 and G7 were classified as genotypes having average stability with low yields therefore poor adaptability. 5. The AMMI ANOVA subdivides the GxE effect further using principal component analysis. Genotypes G5 and G9 are classified as having high yields but low stability whereas genotypes G3 and G8 possessed both high yields and high stability. Genotypes G1, G2, G4 and G7 have low yields but are highly stable. Genotype G6 has low yields and low stability. The AMMI model was also used to classify the different locations. Location A and D can differentiate more amongst the genotypes whereas Location Band C have low discrimination amongst the genotypes. 6. According to the ANOVA, genotype G3 was classified as being most stable whereas the Finlay and Wilkinson, and the AMMI models identified genotype G8 as being most stable. The ANOVA ranked genotype G8 fourth for stability. Both AMMI and Finlay and Wilkinson models ranked genotype G1 fifth for stability but according to the ANOVA it was most unstable. Finlay and Wilkinson identified genotype G7 as being the most unstable while the most unstable genotype in the AMMI analysis was G6. The correlations between the stability rankings of the genotypes for the different methods were relatively low. 7. According to the estimated variance of a variety mean, two years, six locations and two replications is the optimum number of years, locations and replications for efficient testing of snap beans for yield in South Africa.
Afrikaans: 1. Die doel van die studie is om die betekenisvolheid van GxE vir opbrengs by groenbone te ondersoek. Tweedens om die verskillende analitiese metodes vir die beskrywing van genotipe x omgewingsinteraksie met mekaar te vergelyk. Derdens om die optimale aantal lokaliteite, jare en herhalings vir doeltreffende evaluering te bepaal. 2. Nege groenboon variëteite is ingesluit in die proewe wat op vier lokaliteite oor 'n tydperk van drie jaar (1998-2000) aangeplant is. Die perseelopbrengste is bepaal. Die data is met behulp van ANOVA, Finlay and Wilkinson en AMMI modelle, geannaliseer. Variansiekomponente is beraam om die invloed van die verskillende effekte op die teoretiese variansie van 'n gemiddeld te bereken, ten einde die optimale allokasie van lokaliteite, jare en herhalings te bepaal. 3. Die GxL, GxY en GxYxL interaksies was betekenisvol vir opbrengs. Die beraamde variansiekomponente vir opbrengs toon dat cr 2 g" cr 2 g1, cr 2 gy en cr 2 9ly onderskeidelik 23.5, 18.8,4.9, en 34.8 persent van die totale fenotipiese variansie verklaar. Die bydrae van die fout variansie was 18.0 persent. 4. Volgens Finlay en Wilkinson beskik genotipes G3, G5 en G9 oor gemiddelde stabiliteit met 'n hoë opbrengs met ander woorde oor goeie aanpasbaarheid. Genotipe G8 beskik oor bogemiddelde stabiliteit, terwyl G1, G2, G4, G6 en G7 geklassifiseer kan word as genotipes met gemiddelde stabiliteit en lae opbrengs met ander woorde lae aanpasbaarheid. 5. Die AMMI ANOVA onderverdeel die G X E effekte by wyse van hoofkomponent ontledings. Genotipes G5 en G9 word volgens die metode geklassifiseer as genotipes met lae stabiliteit en hoë opbrengste. Genotipes G3 en G8 beskik oor hoë stabiliteit tesame met hoë opbrengste. Genotipes G1, G2, G4 en G7 is hoogs stabiel met lae opbrengste. Genotipe G6 beskik oor lae stabiliteit en lae opbrengs. Die AMMI model is ook gebruik om die verskillende lokaliteite te klassifiseer. Lokaliteite A en D differensieer tot 'n groter mate tussen genotipes, terwyl lokaliteite B en C tot 'n mindere mate tussen genotipes diskrimineer. 6. Volgens die variansie-ontleding word genotipe G3 as meer stabiel geklassifiseer, terwyl die Finlay & Wilkinson en AMMI modelle genotipe GB as die mees stabiele identifiseer. Die variansie-ontleding het genotipe GB vierde beste vir stabiliteit gegroepeer. Beide die AMMI en Finlay and Wilkinson modelle het genotipe G1 vyfde vir stabiliteit gegroepeer, maar volgens die variansie-ontleding is die genotipe hoogs onstabiel. Finlay & Wilkinson het G7 as die mees, onstabiel genotipe geïdentifiseer, terwyl die AMMI ontleding genotipe G6 as die mees onstabiele genotipe geklassifiseer het. Die korrelasies tussen die stabiliteits . rangordes van die genotipes vir die verskillende modelle is relatief laag. 7. Volgens die beraamde variansies van 'n cultivar gemiddelde is twee jaar, ses lokaliteite en twee replikasies die optimale aantal jare, lokaliteite en herhalings om groenbone vir opbrengs in Suid-Afrika doeltreffend te evalueer.
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Common bean -- Genetics, Genotype-environment interaction, Crops -- Genetics, Dissertation (M.Sc. Agric. (Plant Breeding))--University of the Free State, 2000
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