When Gregor Mendel died in 1884, he passed in relative obscurity.
Cultivating a five-acre plot on the grounds of his monastery, the Austrian monk went unrecognized during his lifetime for having cracked the fundamental laws of biological inheritance through his experiments on garden peas. Today, he’s credited with founding the modern science of genetic engineering, his trials respected for their simplicity and rigor.
For the last two decades, a far more genetically complex crop has captivated Lise Mahoney, a research scientist at the University of New Hampshire: the strawberry, with eight sets of chromosomes that quadruple the humble pea’s genome, composed only of two sets.
Mahoney has bred six varieties of strawberries for optimal survival in New Hampshire’s temperamental climate, which she hopes will pass muster with a third-party evaluator and eventually become commercially available. They may be anonymous at this minute, like Mendel’s peas in his lifetime, but Mahoney hopes a day will come when one of her varieties changes how the bright, sweet-tart fruit is grown and eaten in the Granite State.
“The naming process comes later. All my plants, they just have numbers right now, like 156-dash-8,” Mahoney said, vaulting from one end of her greenhouse at UNH to another, inspecting her strawberry plants. “The varieties that are being evaluated commercially right now — fingers crossed they rise to the occasion.”
A long tentacle curls from one of Mahoney’s strawberry plants, a ‘runner’ intermittently punctuated by clusters of nodes called root nodules that, when placed in contact with soil, can grow roots and produce a new strawberry plant. In New Hampshire, propagating with root nodules is a standard approach for cultivating strawberries, but on a commercial scale, the method requires intensive attention to blight prevention and pest control.
“In mass production, they would collect a whole bunch of these and root them all in the field. Then when they’re rooted, they go through and they dig them all out, but they’ve had to steam and fumigate this field to make sure there aren’t any diseases,” she said. “Can you imagine?”
Patience through generations of selective inbreeding earned Mahoney her six “fittest” varieties. They represent a fraction of the 20 she’s cultivated over her two decades working across UNH’s MacFarlane’s Research Greenhouses and Woodman Horticultural Research Farm in Durham, but they hold promise.
These varieties don’t require such complicated pest control, as they’re propagated from seeds rather than runners. Magnified on a research poster displayed by Mahoney’s office, a strawberry seed appears scarlet red, oblong and gleaming, like a human organ. Seeds still need to be sanitized, but that process isn’t nearly as labor-intensive, she said.
As “day neutral” varieties, these have the advantage of producing fruit throughout the summer, unconfined by the conventional strawberry’s season’s three-week sprint in mid-June. Other day-neutral strawberry varieties exist, cultivated in California and Florida, but according to Mahoney, none but hers have been specifically developed to resist New England’s ferocious winters.
“They tasted good, they produced a lot of fruit, they had overwintered well and they were inherently resistant because I don’t treat for any diseases. If a plant isn’t resistant, it’s not going to do well,” she said. “I could still use organically approved pesticides, but I didn’t do that either.”
As Mahoney bred novel varieties, UNH Professor Rebecca Sideman probed how best to cultivate existing varieties already widely used in the northeast.
Sideman, chair of the Department of Agriculture, Nutrition and Food Systems, observed that a technology called low tunnels could protect strawberries from inclement weather, prevent disease by limiting standing water and improve the quality of the fruit.
These inexpensive plastic canopies resembling stout greenhouses require maintenance that, for more diversified farms, may not be worth the trouble. But “it would make sense as an investment if strawberries were your primary crop. It’s kind of insurance against bad weather,” she said.
When winters rage, Sideman’s more recent research in collaboration with Cornell Extension indicates that two approaches to covering strawberry plants, one considered standard and the other a more novel alternative, are about equally protective. Through a years-long trial in New York and New Hampshire, Sideman pitted conventional straw mulch against lightweight spun sheets called row covers.
“Sometimes the straw outperforms the row covers; in many cases, the row covers were just as good, but both are better than not mulching at all,” she said.
At the MacFarlane Research Greenhouses, a maze-like compound of sunwashed rooms, Mahoney works on ornamental strawberry plants that flower in vibrant hues and hold horticultural value for gardeners.
A fledgling fruit, a green nub the size of a fingernail, pokes out from a leafy crown. Bred for heightened cyanidin, an organic compound with powerful antioxidant properties and strong pigment, the strawberry will ripen a dark red and taste almost like raspberries.
With each generation of inbreeding, Mahoney inches closer to the strawberry traits she’s seeking. Whether they’re bred primarily for appearance, flavor or resistance to the local climate, these bellwether plants might change the strawberry-rhubarb pies, crisps and crumbles of future summers in the Granite State.
“The combination of doing research, developing new varieties and also studying how to best manage these varieties people have access to already — that’s a powerful combo,” said Sideman. “Strawberries freshly picked, ripe from the plant, have so many aromatic compounds. They’re so flavorful compared to ones that are picked less ripe and shipped long distances. Making the extra effort to try to optimize local ones, for anyone who likes strawberries, that’s everything.”
