Abstract:

In order to select special nut-processed cultivars, we measured and analyzed a number of economic indexes of 43 cultivars and varieties of 5-6 years old Ping'ou hybrid hazelnuts (Corylus heterophylla × C. avellana) planted in the same orchard with identical management at Anqiu county, Shandong province. The processing traits of the nuts and kernels were measured and the traits were graded according to the forestry industry criteria and China Fruit's Monograph. The results showed that nut weight varied from 1.45 g to 3.30 g, nut shape index varied from 0.67 to 1.08, kernel weight varied from 0.76 g to 1.44 g, shell thickness varied from 0.90 mm to 1.76 mm and kernel weight percentage varied from 35.06% to 56.00%. The processing traits, such as nut size, plumpness of the kernel, thickness of the shell and kernel percentage of most candidates reached to relative higher grades of the industry standards, indicating the high potential selectivity in the population. There were significant differences in the economic traits among the candidate cultivars and varieties and the variation coefficients (CV) were 5.30%-70.31%. There were to different degrees relationships between paired traits, which should be considered for the cultivar selection. However, there were small amount of round nut types in the population, which was a limiting factor in the selection of nut-processed cultivars. Based on this study, the main traits and criteria for selecting special nut-processed cultivars included in turn, nut weight ≥ 2.00 g, kernel weight percentage ≥ 40%, kernel plumpness 0.80-0.90, kernel weight ≥ 0.80 g, round nut (nut shape index 0.90-1.00). Four cultivars and varieties i. e. ‘Liaozhen No. 2', ‘Ping'ou 30', ‘Ping'ou 90' and ‘Ping'ou 28' were selected as the special nut-processed cultivars.

Key words: Corylus heterophylla×C. avellana, nut, kernel, processing traits