Grafting success of walnut (Juglans regia L.) varieties in controlled environments

Although one of the most important gene centers in Europe is Turkey for walnut, unfortunately, Turkey has not reached the desired level of production and exportation. In recent years, production has failed to meet walnut demand in the domestic market. Also, walnut exportation has been increasing year by year. In this context, Turkish Government incentives to the private sector for the production of certified walnut saplings gains importance. In this study, it is aimed to determine the most suitable walnut varieties which are best suited to combed walnut for the production of grafted walnut seedlings in order to meet the demand for walnut seedlings and to determine the most suitable grafting fusing environments. In this study, the seeds collected in naturally growing walnuts in Taraklı region for 2016. A part of the seeds were planted in polyethylene tubes measuring 20x35 cm. 1: 1: 1 ratio of forest soil, peat and perlite in tube mortar used. Seeds were sown on planting seedbed in Duzce Forest Nursery. It has been used in grafting studies on wild walnut seedlings which are 2 years old. A total of 15 walnut varieties were used to graft to the two years old wild walnut seedlings. The grafting was carried out on 21-22 April 2018. The grafted materials obtained from 9 native (Yalova1, Yalova3, Yalova4, Şebin, Kaman, Kaplan, Oguzlar, Sapanca and Bilecik) and 6 nonnative (Fernor, Franquette, Fernette,Pedro, Chandler, Ronde) varieties. They are used for automatic greenhouse temperature and humidity controllable (24 ° C and 60-70% humidity), uncontrollable greenhouse and outdoor (outdoor planting seedbed). Grafting studies were performed on 21-22 April 2018 and the graftings were checked for 40 days later. The grafting success was counted on 30-31 May 2018. The highest grafting success rate was 82.72% in control greenhouse in walnut varieties, while the lowest success rate was obtained in open fields with 52.12%. The highest grafting successes were Oğuzlar77 (80,92%), Chandler (76,66%), Fernette (72,96%) and Franquette (72,22%), Ronde (50,55%) and Bilecik (52,59%) varieties, respectively. When the environment and variety interactions were examined, all of the vaccines of Franquette cultivars in the controlled environment (100%) were kept. However, 20% success was achieved in Ronde de montiac cultivar in open field. According to these results; for walnut grafting, controlled (24-27 degrees 60-90% moist) environments can be recommended as growing medium. However, if a controlled environment cannot be provided, vaccination may be recommended when the average daily temperature is at least 20 degrees in the spring. In addition, Oguzlar, Chandler and Franquette varieties can be used if seedling rootstock Anatolian walnuts are used as litter. Keywords: Graft, Walnut, Juglans regia.