The performance of some walnut (juglans regia) cultivars in the conditions of Bursa, Turkey

Abstract

The present study aimed to evaluate the pomological and phenological traits, as well as yield potential and incidence of external defects of some local ('Bilecik', 'Mara</n> 12', 'Mara</n> 18', 'Sebin', 'Sen 1') and foreign ('Chandler', 'Fernette', 'Fernor', 'Howard', 'Pedro', 'Serr') walnut cultivars grown in Bursa (north-west in Turkey) conditions between 2014 and 2020. The first leafing was observed in Mara</n> 12, Serr, Sebin, and Mara</n> 18 cultivars, while Fernette and Fernor were the last leafing cultivars. The female blooming period of the cultivars was recorded to be the longest in Mara</n> 18 (15 days) and Sebin (16 days) and that was the shortest in Bilecik and Serr (10 days). The male blooming period was recorded as the longest in Chandler, Fernette, Bilecik, and Sebin (16-18 days) and that was the shortest in Mara</n> 12 and Serr (10 days). The average yield per tree of cultivars ranged between 1.87 kg (Sebin) and 14.21 kg (Pedro). Walnut blight was observed on average in 15.85%, sunburn in 10.21%, codling moth in 5.11%, anthracnose in 3.23%, and bird damage in 2.35% of the fruits. The healthy nut percentage ranged from 40.06% (Sen 1) to 76.50% (Chandler). The nut weight of cultivars was between 9.91 g (Mara</n> 12) and 16.27 g (Sen 1). Kernel percentage varied from 36.31% (Sen 1) to 53.56% (Mara</n> 12). The principal component analysis conducted to distinguish the cultivars suggests that the most important factors could be reduced to five components. The results showed that Mara</n> 12, Chandler, Fernor, and Howard were suitable cultivars for commercial cultivation in Bursa conditions.