6 research outputs found
Plant selection in F2 segregating populations of papaya from commercial hybrids.
The objective of this paper was to estimate the genetic parameters and additive genetic values in segregating populations of papaya using the mixed model methodology. Two F2 populations from Tainung and Calimosa hybrids were evaluated. The experimental design was an augmented block with four replicates, and Golden and Calimosa cultivars were the common treatment. Estimates of individual heritability were high for fruit length (FL) and weight (FW), moderate for fruit diameter (FD), and low for total soluble solids (TSS) and fruit firmness (FF). Considering FF and TSS as main traits for selection, genotypes of Calimosa-F2 population showed better performance to FF, but worse concerning TSS. It was selected 18.3% and 24.6% of plants from Tainung-F2 and Calimosa-F2 populations, respectively. Negative correlation between TSS and FF was not able to reduce the genetic gains. The segregating populations from Calimosa hybrid are more promising for the selection of papaya lines
Comportamento produtivo de novos hÃbridos e linhagens de mamoeiro no sul da Bahia.
O Brasil ocupa lugar de destaque na cadeia produtiva do mamoeiro (Carica papaya L.), porém a concentração dos cultivos em um número restrito de variedades dos grupos Formosa e Solo, torna a cultura vulnerável ao ataque de pragas e doenças. Os genótipos do grupo Formosa são constituÃdos principalmente por hÃbridos, sobretudo o Tainung nº1 cujas sementes são importadas e o Calimosa, que é o primeiro hÃbrido nacional de mamão. Diante dos problemas causados pela estreita base genética, aliado aos altos preços das sementes de hÃbridos importadas, alguns produtores brasileiros utilizam as próprias sementes dos hÃbridos F1 nas gerações F2, F3, F4 etc., o que tem levado à perda das caracterÃsticas do hÃbrido original, produzindo frutos com qualidade inferior e totalmente fora do padrão comercial (Costa & Pacova, 2003).pdf 83