Vegetative and fruit characteristics of papaya trees obtained by mass selection

The present work had as purpose to evaluate some characteristics of papaya trees (Carica papaya L.), Golden cultivar, obtained trough plant mass selection, regarding plant and fruit quality in the first months of production. The samples were evaluated in a commercial crop at: 0, 20, 40, 70, 130, 180, 230, 260, 280, 310 and 340 days after the planting (DAP) and the first fruits were harvested at 230 DAP. The results showed the low height (199cm in 340 DAP) and low first flowering`s heigth (71cm), which is important to facilitate the harvest process. The plants presented good yield with high number of leafs (allowing a great area of fruit cover) and about 60 fruits per plant. The fruits kept similar features to cv. Golden. The fruit`s fresh weight ranged from 302.4 to 467.5g, which is in the range of the Brazilian market. The pulp thickness was 2.35cm, which is a feature of great economic interest. The pulp thickness showed close relation with climatic factors, and great variations of temperature and precipitation accelerated the pulp loss of thickness

Estimates of genetic parameters among and within Half-sib families in two selection cycles on the EEL2 maize (Zea mays L.) population

Dois ciclos de seleção entre e dentro de famílias de meios-irmãos foram efetuados na população de milho EEL2, nas regiões Norte, Sul e Serrana do Estado do Espírito Santo, no período de 1987 a 1989. Em cada ciclo, duzentas progênies de meios-irmãos foram avaliadas, usando dois látices 10 x 10 com duas repetições por local. Aplicaram-se os índices de 15% de seleção entre as progênies, e 12,5% entre as progênies na recombinação. Em relação ao caráter peso de espigas, as análises de variância individuais e conjuntas detectaram diferenças significativas para progênies e para a interação progênies x locais. As variâncias genéticas aditivas variaram entre locais e ciclos com valores entre 501,4 e 1002,7 (g/planta)2. Os valores dessas variâncias nas análises conjuntas foram inferiores aos das análises individuais, sendo de 58,0 e 292,7 (g/planta)2 no 1o e 2o ciclo, respectivamente. O ganho genético médio esperado com a seleção do primeiro e segundo ciclo foi de 1,5% e 8,2%, respectivamente. As magnitudes destas estimativas, os altos valores de herdabilidade e dos coeficientes de variações genéticas, associados a altas médias de produtividade das progênies, são indicadores do grande potencial desta população em um programa de melhoramento.Two cycles of selection among and within half-sib families were evaluated on the maize population EEL2, from 1987 to 1989 in the north, south and highland of Espírito Santo State, Brazil, in order to estimate the efficiency of selection for the trait ear weight. Two hundred half-sib families, were evaluated in each cycle, using two latices 10 x 10, with two replications per location. For the cross over, the selection rates of 15% among progenies, and 12.5% within progenies was used. For the trait ear weight, the analysis of variance individual and combined, detected significant differerices for progenies and for the interaction of progenies x locations. The additive genetic variance values varied for locations and cycles, ranging from 501.4 to 1002.7 (g/plant)2. The values of those variances at combined analysis were smaller than the values of individual analysis: 58.0 (g/plant)2 for the first cycle and 292.7 (g/plant)2 for the second cycle. Mean expected gains were 1.5% and 8.2% at first and second cycles, respectively. The magnitude of those estimations, the high values of heritability and of genetic variation coefficients, associated to the high means of progenies productivity, indicate the high potential of this population in a breeding program