A new Chinese chestnut cultivar Yanfeng with top quality, high yield and excellent stress resistance

Yanfeng is a new chestnut cultivar selected through seedling selection. In 2006, the mother tree was found in Qianxi county, Hebei province by our research group, which was determined to be the superior strain after evaluation. In the spring of 2007, the strong juvenile branches of the mother tree were collected and grafted to the Variety Breeding Nursery of Hebei Normal University of Science and Technology, and the main cultivar Yanshanzaofeng was used as the control. Since 2015, regional trials have been carried out in three sites of Hebei province (including Funing, Qianxi and Qian'an). After eight years of trial and investigation, the superior strain showed obviously desirable characteristics such as high quality, high yield and strong resistance. In December 2023, it was approved by Hebei Forest Variety Certification Committee and officially named as Yanfeng. This cultivar is of medium height. The tree is vigorous with spreading tree gesture. The annual branches are brown, and lenticels are small and moderately dense. Leaves are long elliptical and dark green, with 18.9 cm in length and 6.8 cm in width. After grafting for 6 years, the average numbers of male inflorescence and female flowers on mixed flower branches are 11.4 and 2.3, respectively. The shape of burs is oval, with coarse spines of medium density and length. The average weight of a single bur is 39.2 g. The nuts have puce and glossy shells. The faint yellow flesh of nut shows the quality of strong glutinousness, aroma and sweetness. Soluble solids content is above 19%. And the contents of mineral elements per 1 kg of nuts are 510 mg magnesium, 142 mg calcium, 12 mg iron, 6 mg zinc, 73.4 mg manganese, 2.6 mg copper, 3030 mg potassium, 786 mg phosphorus and 14 mg sodium. The fruit development period is 90 days. It matures in early September in Qianxi county, which belongs to the early-mid maturing variety. The average number of fruit branches produced by an original bearing-shoot is 2.7, and the proportion of fruit branches is 70.6%. Each fruit branch has an average of 2.3 burs. Each bur contains an average of 2.8 nuts. The weight of single nut is 8.1 g. After grafting, this variety begins to bear fruits in the 2nd year, and begins to produce abundantly and steadily in the 5th year. The average yield per tree in the 8th year is 3.6 kg, equivalent to a yield of 3 024.0 kg·hm-2, which is higher than the check cultivar Yanshanzaofeng. It has a strong capacity for continuous fruiting, and can produce stable and high yields in successive years under no fertilization condition. The nut has good storage resistance and can be used for stir-frying, making ice chestnuts, etc. Yanfeng is resistant to dry and barren soil. It is able to maintain normal growth in extremely dry parks and years. It is also resistant to red mite, with good stability and adaptability. Suitable cultivation areas are in the Yanshan mountains and areas similar to this ecotype. Orchards should be chosen on gneiss or granite weathered soil. The spacing in the rows and spacing between rows are (2-3) m×(3-4) m. Yanzi and Yanbao are appropriate pollination cultivars for Yanfeng.