Rob's  column covers his picks of the most exciting new hostas soon to be available.

Chemically Induced Tets:
A Sure Fire Method for Success?
   Take an already popular hosta cultivar and intentionally double its ploidy. Seems like a sure fire method for success. Such was the case at the 2010 AHS convention as a trio of chemically induced tetraploids was unveiled in the vending area. In fact if you blinked you may have missed them as they all sold out very quickly. They were “hot” indeed.
   The three plants all come from Dutch plantsman Marco Fransen. The parents of these three sports are all well known and widely grown: ‘Orange Marmalade’, ‘Paradise Island’ and ‘Praying Hands’. Each of these cultivars has enjoyed a quick rise in popularity since introduction owing to their unique characteristics. ‘Orange Marmalade’ adds a new color to the hosta color palette. ‘Paradise Island’ not only offers red petioles that contrast nicely with the brilliant yellow spring foliage,  a narrow green margin also frames the yellow foliage making it even more vivid. And ‘Praying Hands’ is one of the most unique hostas of all time with its narrow upright folded foliage.
   In 2007 Marco had the vision to ask a simple question: “What would these popular cultivars look like if they were converted to tetraploids?” He also had the industry connections to make this happen, or at least attempt to make it happen. A lab in Holland that had prior experience with making lilies tetraploid for the cut flower business was employed by Marco to attempt the conversion. While there were no absolutely guarantees of success, the lab was able to produce a number of selections for each which Marco could pick from.
 Marco Fransen at Trompenburg    photo Jeroen Linneman
   Chemicals used to induce polyploidy in plants (like colchicines – derived from the Autumn Crocus, Colchicum) are often highly poisonous to humans and must be handled very carefully in the lab. Alternately, less toxic pre-emergent type chemicals (like Treflan and Surflan) have been used. Plant exposure to the chemicals yield a wide range of results - stunting, twisting, changes in foliage color and variegation. Sometime they die immediately. Sometimes there is no obvious change at all. Near term survival of many of the resulting plants can be very short owing to very confused, mixed up chromosomes. However you are only looking for that one plant that exhibits the stable characteristics of a tetraploid. 
   In hostas we usually associate tetraploids with increased substance, a wider margin with variegated hostas, stiffer petioles yielding a more upright growing habit, and slightly larger (wider, not longer) flowers as compared to its diploid counterpart. That is what Marco was looking for. He made the final selections based on uniformity to what he had hoped to achieve in a tetraploid form of the parent plant.
   After growing these selections on for another year, combined with the experience he already had with the parent plant, he decided these new plants were ready for introduction. Ben Zonneveld of Holland subsequently measured all three cultivars using flow cytometry and confirmed they are all fully tetraploid while the parent in each case is diploid.
   And so without further adieu let me introduce you to this trio of titillating tets:
   ‘Forbidden Fruit’ is tetraploid sport of ‘Orange Marmalade’. It maintains the same unique yellow-orange color as its parent, but with a wider blue-green margin. With a little more green in the leaf overall vigor is increased even as a tetraploid.
   ‘Hands Up’ is a tetraploid sport of ‘Praying Hands’. It is shorter, stiffer and more upright than its parent. The yellow margin is more defined and obvious than its parent.
   ‘Volcano Island’ is a tetraploid sport of ‘Paradise Island’. A wider green margin makes for an even more striking contrast with the vivid yellow center. A more upright growing habit helps to really show off the red petioles.

'Forbidden Fruit'

'Hands Up'

'Volcano Island'

    With the investment Marco has already made in these three new cultivars, it comes as no surprise that he has also applied for plant patents in both the United States and in Europe. He is also working on AHS registration.  Look for them all to be more widely available in 2011.
   With the success of chemically induced tetraploids, could an octoploid hosta be far away?

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