Ancient Method Helps Feed Present-Day Communities

In remote villages and rural towns from Guatemala to Costa Rica, horticulture professor James Nienhuis and his former grad student Erick Gutiérrez MS’17 are improving countless lives, one tomato seedling at a time. Their goal is to combat the region’s agricultural afflictions (viruses and soil pathogens) to ease the hardships of growing food and earning a living. They’re doing this with a technique older than the ruins of Tikal.

The roots of the initiative go back about eight years when Nienhuis established Seeds of Hope with a USAID grant. His goal was to combat the whitefly-transmitted geminivirus in Central America by developing genetically resistant cultivars that are still beautiful and flavorful.

Erick Gutiérrez teaches grafting to farmers in the small Guatemalan village of San José Sigüila. Photos: Brenda Dawson, UC Davis

Erick Gutiérrez teaches grafting to farmers in the small Guatemalan village of San José Sigüila. Photos: Brenda Dawson, UC Davis

Nienhuis produced the cultivars he needed to withstand the virus, but other soil pathogens — fungal, bacterial, and parasitic — continued to spoil tomato crops, slashing yields and decreasing the income and nutrition levels among the rural poor.

“Ralstonia (a bacterial wilt) kills the plant once symptoms develop. It causes serious yield losses,” says Gutiérrez, a native of Honduras. “It is very hard to eradicate.”

Matthew Kleinhenz PhD ’96, Nienhuis’ former student, asked if he had tried grafting as a possible solution. Seeing merit in the idea, Nienhuis shifted focus and launched a new program called Seedlings of Hope. The idea was to unite the upper portions (scions) of his virus-resistant cultivars with soil pathogen-resistant rootstocks. Solanum habrochaites, a wild tomato plant that thrives in diseased soil, was a prime candidate to serve as the rootstock.

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