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- Author or Editor: E.H. Erickson x
- Journal of the American Society for Horticultural Science x
Abstract
The inability to achieve adequate pollination of seed parents has slowed the development of hybrid carrots (Daucus carota L.) and dampened industry acceptance. Thus, cytoplasmically male-sterile inbreds and F1 seed parents were compared with their fertile counterparts for synchrony of floral events and character of pollinator foraging stimuli. Usually, but not always, male-sterile plants were visually different, bloomed later, and exhibited delayed nectar and aroma production compared to male-fertiles. The quality and quantity of nectar and aroma were also different, with male-sterile flowers often inferior to fertile flowers in amounts of nectar produced. Successful use of any cross-pollinated entomophilous hybrid crop system should involve selection for similar floral characteristics early in the breeding program to insure maximum transfer by insects of pollen from male-fertile to male-sterile parents.
Abstract
A study of foraging by honey bees (Apis mellifera L.) among cytoplasmically male-sterile and malefertile seed parents of carrot (Daucus carota L.) revealed that honey bee discrimination between the fidelity to carrot phenotype and genotype were evident and often extreme. Some lines were extensively visited while others were virtually ignored. Wide differences in seed set were evident among male-sterile F1’s and inbreds and malefertile lines. Differences in seed yield were correlated with foraging preferences, but the quality of nectar from the stomachs of bees was not.
Abstract
Examination of flowers of carrot (Daucus carota L.) using the scanning electron microscope revealed that some cytoplasmically male-sterile genotypes exhibit flower abnormalities that may be associated with reduced pollination and seed set. Such abnormalities, evident in many inbred lines, may carry over to the male-sterile F1 parents used to produce 3-way hybrids and probably affect insect pollinator activity.
Abstract
Nectary development in cytoplasmic male sterile (cms) Brassica campestris L. was partially restored through 3 cycles of selection for nectary size and number. No major anatomical differences between nectaries of normal and cms plants were apparent under light and scanning electron microscopes (SEM). Half-sib family analysis of nectary development showed negligible additive genetic variance but a prominent maternal effect. Differential response to selection observed in 3 pedigrees suggests the possibility of capitalizing on nuclear-cytoplasmic diversity for the improvement of nectary function.