Walnut Pollination and Fertilization :

Pollination is the first step in a plant’s fruit production. In walnut trees, pollination refers to the transfer of pollen grains from the male organ to the stigma of the female organ. The male and female organs are located in different parts of the walnut tree and can function simultaneously.

Pollination in Walnuts:

Pollination in walnut trees occurs through the action of wind. Therefore, it is beneficial to plant pollinators in the direction of prevailing spring and summer winds during garden establishment.

• Male Organs: These are in the form of catkins, present on the tree during the budding period and develop over time. As they mature, the wind carries the pollen to reach the female organ.
• Pollinator Selection: The pollinator plant should be selected according to the walnut variety. For example, the varieties Cisco, Franquette, and Fernette can pollinate the Chandler variety. Planting these in the orchard at a rate of 5% can prevent pollination issues.

Fertilization in Walnuts:

Fertilization is the next stage after pollination. When matured female organs meet with pollen grains, pollination occurs, and fertilization is about to take place for the development of the fruit. A tree that successfully undergoes fertilization can produce fruit efficiently.

Walnut Pollinator Selection:

Step 1:Pollination Timing

1. Flowering Overlap: Ensure that the male and female flowers of the selected varieties bloom at the same time. This increases the chances of effective pollination.
2. Protandry and Protogyny: Walnuts can be either protandrous (male flowers mature first) or protogynous (female flowers mature first). Choosing complementary types can improve pollination success.

Step 2:Compatible Varieties

Common Pollinator Cultivars:

• Chandler: Best paired with Franquette and Cisco for effective pollination.
• Pedro: Similar to Chandler, Franquette and Cisco are recommended pollinators.
• Fernor: Best pollinated by Fernette and Franquette.
• Hartley: Franquette and Amigo are suitable pollinators.
• Payne: Can be effectively pollinated by Chandler, Hartley, and Chico.
• Fernette: Fernor is the recommended pollinator.
• Yalova-1: Pairs well with Şebin and Kaplan-86.
• Yalova-2: Pollinators include Yalova-1, Şebin, and Bilecik.
• Yalova-3: Best paired with Yalova-1, Bilecik, and Tokat.
• Yalova-4: Yalova-1 and Kaplan-86 are suitable pollinators.
• Bilecik: Compatible with Şebin, Yalova-3, and Yavuz-1.
• Şebin: Best pollinated by Bilecik, Yavuz-1, and Şen-1.
• Kaman: Bilecik and Şebin are recommended pollinators.
• Yavuz-1: Suitable pollinators are Şebin, Bilecik, and Yalova-3.

When selecting pollinators, it’s essential to consider the overlap in flowering times to ensure successful pollination. Also, considering the regional adaptability and disease resistance of each variety can further enhance the productivity and health of your walnut orchard.

Regional Adaptations: Some cultivars perform better in specific regions due to climate and soil preferences. It’s important to choose varieties that are well-adapted to your local conditions.

Step 3:Planting Strategy

1. Spacing: Ensure adequate spacing between trees to allow for air circulation and light penetration, which are important for both tree health and pollination.
2. Arrangement: Interplanting different cultivars can enhance cross-pollination. For example, alternating rows of different varieties or planting pollinator trees at strategic locations within an orchard.

Additional Tips

1. Pollinator Density: Having a higher density of pollinator trees can improve pollination rates.
2. Environmental Factors: Wind plays a significant role in walnut pollination. Planting in areas with good air movement can help disperse pollen effectively.
3. Disease Resistance: Choose varieties that are resistant to common diseases in your area to ensure the health and productivity of your trees.

By carefully selecting and managing walnut pollinators, you can significantly improve the productivity and quality of your walnut orchard. For the best results, consider consulting local agricultural extension services or walnut grower associations for region-specific recommendations.Helper pollinator walnut trees can be planted in the orchard at a rate of 5-10%.

Pollination Problems and Early Fruit Drop:

Insufficient Pollination:

Insufficient pollination occurs when pollen grains fail to reach the female organ adequately or when the female organ fails to retain the pollen. In this case, fruits drop before ripening.

Excessive Pollination:

Excessive pollination occurs when an excessive amount of pollen reaches the female organ. In this case, fruits also drop before ripening.

Preventing Early Fruit Drop:

• Select an appropriate walnut variety for the orchard and plant pollinator trees in the necessary amounts.
• Conduct soil analysis to address any nutrient deficiencies.
• Regular pruning of trees should be performed.
• Take necessary measures against diseases and pests.

Note: This information is provided for general purposes only. For more detailed information on walnut cultivation, you can seek assistance from the Ministry of Agriculture and Forestry or agricultural engineers.