IS 4-6

Technical Profile of the IS 4-6 Rootstock

IS 4-6 is a specialized rootstock developed by the Institute of Horticulture of the National Academy of Agrarian Sciences of Ukraine, designed for high-performance pear orchards. The primary technical value of this rootstock lies in its balance between moderate growth vigor and exceptional winter hardiness, making it an essential solution for temperate climates prone to severe ground freezing.

Engineering Characteristics and Compatibility

• Growth Vigor: Classified as a semi-dwarf (medium-growing) rootstock. It provides an optimal balance between canopy development and fruit load, facilitating efficient orchard management and tree maintenance.
• Graft Compatibility: Perfectly adapted for pear scions. IS 4-6 demonstrates high graft take rates and structurally sound tissue union, ensuring long-term tree health without the necrosis issues often found in incompatible interspecific grafting.
• Winter Hardiness: With a cold resistance threshold of down to -35°C, this rootstock outperforms many imported alternatives, making it ideal for regions where standard quince rootstocks are prone to winter damage.
• Phytosanitary Resistance: High resistance to septoria and pear scab (Venturia pyrina) significantly reduces the need for frequent fungicide applications in the nursery, leading to cleaner, more vigorous planting material.

Practical Impact for Producers

Utilizing IS 4-6 enables growers to achieve initial fruiting within 3-4 years. For commercial operations, this accelerated production cycle is key to rapid return on investment. The rootstock's high adaptability to diverse soil conditions, combined with its robust disease resistance, makes it a reliable biological foundation for establishing productive and long-lasting pear orchards.