A new Prunus salicina Lindl. var. cordata cultivar ‘Gutianzaonai ’

Abstract: Nai plum (Prunus salicina), a member of the Rosaceae family, originated from China. It is al- so a famous fruit crop in the Fujian province of China due to its characteristic taste, aroma and flavour. As early as the 1970s and 1980s, it was widely promoted in Gutian county, Pucheng county, Yongtai county, Guangze county, and Fuzhou city in Fujian province. It has become a green industry in the province and a rich industry for farmers. However, there are many problems in production, such as structure onefold, a large number of mid-maturing varieties, concentrated maturity, high-temperature season dur- ing harvest, difficult storage of fruits, and extreme lack of early-maturing varieties. Therefore, cultivat- ing new varieties of early maturity is an important issue that needs to be resolved in order to improve the structure of the plum industry variety in Fujian and extend its market supply period.‘Gutianzaonai’is a new variety of early ripening‘Younai’plums, which is selected from breeding nursery in Xiyang village, Hetang town, Gutian county, Fujian province. It was initially selected in 2000 for its self-fruit- ful characteristic and very early ripening time (it matures from the end of June to early July and meets the requirements for commercial fruit harvesting). After regional adaptability testing at different sites (including Gutian county, Pingnan county, Jianyang county, Qingliu county, Liancheng county of Fujian province), it was finally selected in 2019. This species is a vigorous tree with evenly distributed branches. The young shoot is green, 2-year branch is light gray-brown, perennial branch is gray-brown. The germinating rate is high, and branching ability is strong. The fruit setting mainly depends on short fruit branches and bouquet-shaped fruit branches. Leaves are long oval, 6.93 cm long and 2.45 cm wide, and obtusely serrated. The flowers are bisexual, white and open before the leaves. Fruits are lager, heart- shaped with a pronounced apex. The average weight of fruit is 103.3 g; skin ripens to yellow with thick cuticle wax; pulp is amber yellow, translucent, tender and juicy; it is half- clingstone; edible rate is 97.8%. The content of soluble solids, titratable acid (as malic acid), total sugar and reducing sugar (as glucose) in‘Gutianzaonai’fruit juice is about 12.41%-13.50%, 0.90%-1.06%, 8.4%-9.58% and 6.3%- 7.5%, respectively. The fruit quality is excellent. The period from anthesis to fruit ripening is about 100- 120 d, its time of bud-burst at the middle of February, and full bloom at March, fully mature date in ear- ly July in Gutian county, Fujian province. It matures 20-25 d ahead of time compared to younai. It has good stress resistance and environmental adaptability. Suitable cultivation area is peach and plum plant- ing area of Fujian Province. This variety has a large amount of flowers and good yield. The yield of a 3- year tree is 13.5 kg; the yield of a 5-year tree is 68.5 kg, and the yield per 666.7 m2 is 2 541.9 kg (based on 37 plants per acre). Seedlings should be selected from the winter and spring grafted seedlings of the downy peach rootstock. The depth, width, and length of the cave are 0.8 m × 1.2 m × 1.2 m. Top dress- ing was performed 3 times during growth. While applying fertilizer, it can be watered at the same time. Pruning can be done in winter, including erasing redundant branches, dense branches and poor branch- es. Prevention of pests and diseases should be taken seriously, especially control of Monilinia fructicolaand Xanthomonas pruni.