A research and demonstration orchard near Ferrara, Italy, is a horticulturist’s dream—a 25-acre plot to study rootstocks, varieties, and training systems for pears, apples, and cherries that’s funded by a private foundation without worry of budget cutbacks. And, how about a $3.5-million donation just for pears for the next five years?
Stefano Musacchi of the University of Bologna serves on the technical committee of the Fratelli Navarra Foundation for Agriculture and helps guide research at the foundation’s demonstration block. The foundation was created by the Navarra brothers Gustavo and Severino in the 1920s to support students at the Fratelli Navarra Agricultural Technical Institute and provide funding for practical research for growers. Five years ago, a local chamber of commerce, private bank, and related industries saw a need for more local research on variety selection and provided money for a new 25-acre research orchard, with special emphasis on pears.
Sixty percent of Italy’s pear production is located in the Ferrara, Modena, and Bologna areas, Musacchi said, noting that the Ferrara area has about 72,500 acres of the country’s 105,000 acres of pears. Italy produces about 900,000 tons of pears annually.
“The Po Valley is much different than northern Italy,” Musacchi said during a tour of the demonstration orchard. Elevation in the Ferrara region is near sea level, with some farm ground 30 feet below sea level. Average annual rainfall is 24 to 28 inches, and there is no real temperature difference between day and night during the growing season to bring on blush or crunchy qualities. Also, high humidity can cause russeting, and sunburn can be a problem.
“Here, we can mainly grow Gala and Fuji because the level of quality and production are not comparable to that of South Tyrol,” said Musacchi, adding that they have 14 different Gala and Fuji strains planted in the research trial, along with Pink Lady and Rosy Glow. “Aztec Fuji is one of the best clones for our conditions.”
The new scab-resistant Modi variety is being tested under different training and density systems. “Scab likes our area, with the high humidity and rain. We usually apply at least 20 fungicide applications in a year. But with Modi, we spray once at the beginning of the season and that’s about it.”
Apple training systems under trial include the vertical or freestanding spindle, solaxe (centrifugal), biaxis, and triaxis or vertical cordon. An Italian nursery has developed and patented trees with double leaders used in the biaxis system.
High-density cherry orchard systems are also being studied in the research orchard. Regina, Ferrovia, and Kordia cultivars are planted on Gisela 5 rootstock under the vertical axis spindle and V systems with 1,430 to 2,850 trees per acre. Most cherry growers in Italy sell directly to consumers on the roadside, Musacchi said, adding that cherries are extra income for apple and pear growers.
A pear rootstock trial began in 2005 to evaluate five quince rootstocks: Sydo, BA 29, Adams, C, and H, with interstems used on C because of incompatibility with some varieties. Quince H is the standard rootstock used in Italy. Musacchi said the industry is looking for dwarfing to semidwarfing rootstocks that can produce good fruit size. Cultivars planted in the trial include Abate Fetel, Kaiser, Conference, and the new variety Carmen.
Several different training systems are under study in the pear trial, from the tall spindle and solaxe, to the V, biaxis, and vertical cordon systems. “In pears, you need vigor to produce good quality fruit, while in apples, it’s about controlling the vigor,” Musacchi said. “In pears, the best production is on the larger of the two biaxis leaders, but in apples, it’s the opposite.”
Tree density and spacing vary between the systems, ranging from 1,200 to 5,330 trees per acre with 10 to 11 feet between rows and 1 to 2.5 feet between trees. Researchers want to learn the physiological and economic limits of increasing density.
Ultra-high-density pears were popular ten years ago, with more than 5,300 trees per acre. Such plantings were productive—60 bins per acre—but often fruit size was an issue. “Before, small fruit in the 60-millimeter [2.4 inch] size was okay, but now the market wants at least 70 [2.8 inches],” he said, adding that small sizes bring half the price of larger fruit. “It’s better to produce 30 to 35 tons of good quality fruit than 50 tons of low quality.”
His preference so far from the pear trials is the spindle system, and he would plant 1,200 to 1,400 trees per acre on Adams or Sydo rootstock. A drawback of the spindle is that it can’t be completely mechanized.
In apples, he prefers the biaxis system for vigorous varieties like Fuji because the system can easily be mechanized for pruning and thinning. Musacchi said productivity levels in the apple trial planted in 2005 have been similar between the biaxis and spindle.
“Initially you have good light throughout the trees, but when the bottom of the spindle grows out, it shades out the bottom. Color is very important if you want to be profitable,” he said.
He believes distributing fruit over two axes gives good control of vigor.
The solaxe system worked well when the industry could use carbaryl (Sevin) as a chemical thinning agent, he said. But now, other chemical thinning agents are not as consistent.