Estimates of annual genetic parameters and expected gains in the second cycle of Hevea genotype selection
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TextPublication details: Crop Breeding and Applied Biotechnology 2005Description: 55-63Subject(s): Summary: Genetic parameters and expected gains with selection were estimated for 13 years of girth and six years of rubber yield in 25 rubber [Hevea brasiliensis (Willd.Adr. ex. Juss) Muell-Arg] tree genotypes, selected in the northwestern region of Sao Paulo state, Brazil. There were significant differences among genotypes for both the girth growth and annual rubber yield measurements. A decrease of heritability values with increasing tree age was observed. Heritabilities for annual girth growth on the single plot basis varied from h2p = 0.45 in the 13th to h2p = 0.75 in the third year. For annual rubber yields the values ranged from h2p = 0.60 to h2p = 0.80 in the fourth and third year, respectively. The amounts of genetic and phenotypic variation indicate that moderate gain from selection is possible in breeding programs for annual girth growth while smaller gains can be achieved for annual rubber yield. Genotypic and phenotypic correlation coefficients were generally higher between relatively close ages.
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Journals
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RRII Library Botany | Volume 5, Issue 1 | Journals |
Genetic parameters and expected gains with selection were estimated for 13 years of girth and six years of rubber yield in 25 rubber [Hevea brasiliensis (Willd.Adr. ex. Juss) Muell-Arg] tree genotypes, selected in the northwestern region of Sao Paulo state, Brazil. There were significant differences among genotypes for both the girth growth and annual rubber yield measurements. A decrease of heritability values with increasing tree age was observed. Heritabilities for annual girth growth on the single plot basis varied from h2p = 0.45 in the 13th to h2p = 0.75 in the third year. For annual rubber yields the values ranged from h2p = 0.60 to h2p = 0.80 in the fourth and third year, respectively. The amounts of genetic and phenotypic variation indicate that moderate gain from selection is possible in breeding programs for annual girth growth while smaller gains can be achieved for annual rubber yield. Genotypic and phenotypic correlation coefficients were generally higher between relatively close ages.
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