Cross Pollination of Daylilies

When plant geneticist A.B. Stout solved the mystery of the tawny daylily’s self-sterility in the 1930s, he founded an industry that provides one of today’s popular perennials. He also established a protocol for hobbyists and amateur daylily hybridizers.

Identification

• Hemerocallis, the daylily, is a fleshy rooted herbaceous perennial with lily-like flowers that bloom in daily succession on branched scapes over mounds of grass-like foliage.

The Facts

• The black anthers will be removed before cross-pollination of this daylily.

  Daylilies have six anthers for every stigma in a flower. Cross pollination requires that pollen be transferred from the anther of one plant to the stigma of another, dissimilar plant.

The Process

• Hybridizers transfer pollen with small brushes and remove anthers on the receiving plant to keep accurate records of crosses. They harvest seeds from the pods that form.

Ploidy

• Daylilies cross-pollinate successfully with plants of identical ploidy only. Tawny daylilies and their fulvous offspring have three sets of chromosomes that determine their traits. Diploid plants have chromosomes from two sets of parents. Today’s hybrids are diploid or tetraploid (four sets of chromosomes).

Significance

• Cross-pollinating created daylilies with a wider range of color, fern-like foliage, compact and giant plants, and a variety of flower forms and markings. Without hybridizers and hobbyists, the self-sterile daylily would still be a straggly roadside triploid.