Breeding of a new non-transgene and small-fruit-sized papaya cultivar Huanghuayou

Abstract: Huahuangyou is a new high-quality fruit papaya cultivar, which was crossed between Taiguohong (female parent) and the small fruit Hawaiian type GZ201301301 (male parent) by the Institute of Fruit Research, Guangdong Academy of Agricultural Sciences in 2016 and 358 hybrid seeds were obtained. In December 2016, the hybrid seeds were sown in nutrient pots in a greenhouse, and 296 healthy seedlings were obtained through conventional water and fertilizer management. Those seedlings were planted in Guangzhou Experiment Base in February 2017. According to the breeding purpose for high yield, high quality and good commercial appeal, Huahuangyou was first selected in 2017. After variety test and regional adaptability test at Guangzhou, Foshan and Zhanjiang from 2019 to 2021, it was finally selected in 2021. The plant grows vigorously with high temperature resistance, the average plant height is 288.5 cm and the crown width is 298.7 cm. The stem of the adult plant is cylindrical, gray green and hollow with 218.5 cm high and 48.3 cm thick. The leaves are dark green and the average leaf length and the width are 87.1 cm and 93.8 cm, respectively. The veins are clear and green, and the petiole is 98.2 cm long and 11.5 cm thick. The corolla is yellow while, the base is yellow green, and the corolla length and diameter are 3.7 cm and 3.2 cm, respectively. The main axis of the inflorescence isgreen, and the average length is about 8.8 cm. The fruit is pear- shaped with high regularity, the fruit stalk is green with an average length of about 3.5 cm, the peel of the fruit is smooth and orange yellow after ripening. The flesh is of superior quality, with orange-red color, and the taste is tender, smooth and sweet. The longitudinal and transverse diameters of the fruit are 17.3 cm and 10.3 cm, respectively. The ratio of longitudinal to transverse diameters is 1.68, and the average width of the middle fruit cavity is about 5.0 cm. The contents of soluble solid, reducing sugar, total sugar, total acid, Vitamin C and crude fiber are 13.5%, 10.5 g·100 g^-1 , 12.8 g·100 g^-1 , 0.16 g·100 g-1 , 84.7 mg·100 g^-1  and 0.5 g·100 g^-1 , respectively. The period from planting to first flowering and planting to first harvesting was about 59 d and 177 d, respectively when the tissue culture seedlings were planted in the Pearl River Delta Region in spring. This cultivar has high yield performance, and the average number of commercial fruits per plant is 71.8 with the average single fruit weight being 790.3 g, the average yield per plant is 56.8 kg in the year of planting, and the yield is 6816 kg per 666.7 m² in the case of planting 120 plants. The storage period under normal temperature is 7 days. The variety has strong adaptability, but it is susceptible to papaya ring spot and malformed virus disease. It is suitable for cultivation in the papaya producing areas in China and suggested to adopt rotation planting mode for sake of the prevention and control of virus disease.