Breeding of kiwifruit new cultivar Pingyuanhong

Abstract: Pingyuanhong kiwifruit is a new cultivar selected from the seedlings of Hongyang kiwifruit. In 2010, the natural pollinated fruits of Hongyang kiwifruit were collected, and the seeds were dried by air at room temperature. After storage at 4 °C for six months, the seeds were sown in the research base of West Anhui Kiwifruit Research Institute in April of 2011. A total of 612 seedlings were obtained. From 2012 to 2014, each of the fruiting plants in the progeny was observed. It was found that the red en- docarp of the most strains and Hongyang kiwifruit faded or did not show red again, after experienced continuous high temperature in summer, but the red endocarp coloration of the strain HY520 in the progeny was significantly better than that of Hongyang kiwifruit, which was temporarily named as Pingyuanhong kiwifruit. A regional test was carried out from 2015 to 2019 in Anhui province, and the phenological period, growth and fruiting habits, fruit economic characters and storability of Pingyuan- hong were systematically studied in compare with Hongyang kiwifruit. The results showed that Pingyu- anhong kiwifruit had oval shape, hollow navel, yellow flesh, and radial red endocarp, which was better than that of Hongyang at the same block in plain areas, although having been experienced continuous high temperature in summer. Fruit apex flat or slightly convex and pericarp yellowish green. The fruit average weight was 80.2 g, soluble solid content was 20.9%, sugar content was 14.6%, vitamin C con- tent was 274.6 mg·100 g-1, and acid content was 0.41%. The fruit can be stored for 1-2 weeks at room temperature and more than 3 months at the temperature of 2-3 °C. The shelf life is longer, 15-20 days at room temperature and 30-40 days at low temperature of 4 °C. In Lu’an area of Anhui, the flowers be- gin on April 12, peak on April 14, and end on April 19, berry maturity on September 1, fruit develop- ment period is about 138 days, harvest period is 6 days earlier than Hongyang kiwifruit. The leaves of  Pingyuanhong kiwifruit are heart-shaped, with gray white fuzz, pointed or slightly obtuse apex, serrated margins, purplish red young, pale green adult, and prominent veins on the back. The new shoots are light green, 1-year-old branches are gray white, 2-year-old branches are light brown, lenticels are oval and brown. The flowers are small, milky white, with 6-9 petals and calyx. The budding rate was 37.54%, the branch formation rate was 29.36%, and the fruiting branches accounted for 54.78%, which mainly came from the 1st to 10th node of the mother branches, and the fruit set was as high as 89.25% of flowers. The suitable planting density of this variety is 2 m between plants and 4 m between rows, and‘one trunk with two main vines’is adopted. It is necessary to plant enough male pollinizers, and the ratio of male to female trees should be 6-8∶1. In case of low temperature, overcast and rainy and other unfavorable weather for pollination during flowering, artificial pollination should be carried out in time, and it is bet- ter to raise bees in the orchard at full bloom period to improve the fruit set. The fertilization was mainly organic fertilizer, combined with the suitable amounts of macro-, medium-, and trace-elements. The con- trol of canker and soft rot diseases should be paid attention to in growing season. In the fifth year after planting, the yield of grafted trees was high, stable, and more than 1000 kg per 666.7 m2. It is suitable for cultivation in the Dabie Mountain, Southern Anhui Mountain, and Jianghuai Valley areas. In 2020, it was approved by Anhui Forest Variety Approval Committee (Accession No.: Wan S-SV-AC-002-2020).