Showing papers by "Raphael A. Stern published in 2001"

Sequential introduction of honeybee colonies and doubling their density increases cross-pollination, fruit-set and yield in ‘Red Delicious’ apple

Abstract: SummaryThe ‘Red Delicious’ apple exhibits full self-incompatibility, therefore its fruit production depends totally on cross pollination, especially by honeybees, which are the ultimate apple pollinators. In the present study, the technique of sequential introduction of honeybee colonies and doubling their density was applied to determine effects on yield. In three consecutive season it was found that sequentially increasing the density of colonies in the apple orchards from 2.5 colonies per ha., as recommended previously, to 5.0 colonies per ha, and introducing them sequentially (half at the 10% full bloom (FB) and half at FB), increased the number of bees per tree, their mobility among the rows, and the proportion of “topworkers” compared with “sideworkers” . It seems that a large number of foragers per tree directly increases the amount of pollination, high bee mobility between rows increases the amount of cross-pollination, and a high proportion of “topworkers” increases pollination efficiency. All th...

Determination of the self-fertilization potency of ‘Golden Delicious’ apple

Abstract: Summary‘Golden Delicious’ is one of the main apple cultivars in the world. Apple is a member of the Rosaceae family that harbours the gametophytic self-incompatible fertilization system. The potency of self-incompatibility may vary, depending on the level of rejection of the self-fertilization. Defining the level of self-pollen rejectionhas great horticulture importance since low potency of self-fertilization or total self-pollen rejection result in yield reduction. ‘Golden Delicious’ is considered self-compatible. In this study the potency of the self-fertilization ability of ‘Golden Delicious’ was determined. By implementing PCR-S-allele analysis, self and non-self-fertilization cases were distinguished and accurate self-fertilization levels were identified. From the results, it is apparent that ‘Golden Delicious’ has a very low potency of self-fertilization.