PPDL Picture of the Week

May 31, 2016

The sport of looking for sports

Janna Beckerman, Professor, Botany and Plant Pathology, Purdue University

 

We're not talking baseball, basketball or soccer. We're talking plant sports-- A sport is an offset, or sector of the plant that deviates from the rest of the plant due to a genetic mutation. This genetic mutation results in a segment of the plant that is distinct from its parent both in appearance (phenotype) and genetics (genotype) (Figure 1,2). These sports often have one, or only a few mutations, but otherwise genetically identical to the plant it came from. One popular sport, Harry Lauder's Walking Stick, also called the contorted filbert, was identified in the mid-1800's and has been propagated ever since. Some other famous sports in the horticultural world include hosta cultivars 'Paradigm' derived from 'Abiqua Recluse', 'Guardian Angel' from 'Blue Angel', and 'June' from 'Halcyon'. In fact, there are hundreds of hosta cultivars that began their existence as sports of a more famous parent cultivar.

Sports are not limited to landscape plants. Many fruit varieties are sports, and include the apples 'Grand Gala,' 'Buckeye Gala' and 'Big Red Gala' all derived from 'Gala', and the grape sport 'Frontenac Gris' that is derived from 'Frontenac'. 

Sports don't always give us something new and good:  Dwarf Alberta spruce (Picea glauca 'Conica') is a sport of white spruce (Picea glauca). As these dwarf trees mature, occasional branches develop with needles that appear much longer, which contribute to a more vigorous growth than the surrounding dwarf plant (Figure 3). These sections are called "revertants", which describes the reversion back to the "original" or "wild type" form of white spruce.

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​Click image to enlarge

Figure 1.  The white flowered branch is a sport of lilac ‘Sensation,’ which is known for its white-edged, lilac colored flowers.


Figure 2. Other flowers were showing evidence of this instability.

Figure 3. A reverting branch of dwarf Alberta spruce. Simple pruning of this branch eliminates this problem, although new reversions may develop.