HORNER, HARRY T. Department of Botany and Bessey Microscopy Facility, Iowa State University, Ames, IA 50011-1020. - Soybean floral nectaries and their potential for improving cross-pollination for hybrid soybean production.
Floral nectaries are heteromorphic structures associated with flowers
that produce fluids and/or volatiles that attract a variety of
insects. The attraction is favorable for both insects and flowers,
and enhances the potential for cross-pollination. Soybean flowers are
hermaphroditic and typically self-pollinate even though the floral
nectaries do attract insects and allow for limited cross-pollination.
Presently, there is no commercial production of hybrid soybean.
On-going studies suggest that there are male-sterile soybean lines
that may be suitable for hybrid production. In order to use these
lines effectively, a method for enhanced attraction of insects needs
to be established. Recent results suggest there are soybean lines
whose nectaries seem to produce unusual and/or high levels of
volatiles. The soybean nectary is donut-shaped, encircling the base
of each gynoecium. The nectary ridge contains stomates that exude the
volatiles. Microscopic observations show that the nectaries have a
developmental stage related to volatiles production. Comparison of
these stages among lines that produce unusual and/or varying levels of
volatiles is underway. The goal of this study then is to explore the
developmental and structural aspects of these nectaries as a basis for
further genetic, chemical and molecular research. All of these results
could lead to the genetic engineering of nectaries in selected
male-sterile lines that produce highly attractive volatiles to insure
excellent cross-pollination for hybridization.
Key words: cross-pollination, nectaries, soybean, volatiles