Breeding report of a new midstem banana cultivar Guijiao No. 8 resistant to Fusarium wilt disease

Abstract：The Guijiao No. 8 (AAA Cavendish) is a new banana cultivar selected from the adventitious buds of GCTCV-217-1 (AAA Cavendish) through 60Co-γ radiation induced mutation and pathogen highpressure screening. The new banana variety with medium stem resistance to Fusarium wilt was developed in 2022. Using the adventitious buds of introduced strain as the materials, fifteen strains were selected by 60Co-γ radiation for disease resistance pressure screening. For three consecutive years of experimental planting, six plant lines with excellent horticultural traits and disease resistance were observed. Based on the evaluation of the disease resistance in indoor tissue culture plantlets, one of the plant lines was selected in 2018, and excellent individual plants were selected through multiple site trials from 2019 to 2021.The newly planted banana Guijiao No. 8 had a plant height of 252.7 cm, a petiole length of about 32.4 cm, and a middle circumference and basal circumference of 45.3 cm and 66.4 cm, respectively. The bottom color of pseudostem was dark green. The leaves were upright and the male flower buds were oval in shape. The ear of the fruit was in a long cylindrical shape, with slightly shorter spacing between the stems and compact stems. Under conventional planting conditions, the average yield ofnewly planted bananas could reach 21.5 kg per plant, while the average yield of perennial bananas could reach 23.9 kg per plant. The color of the fruit skin was medium green, the color of the ripe fruit skin was golden yellow, and the color of the fruit flesh was yellow white. The soluble solid content of the fruit was 20.10%, the total soluble sugar content was 19.42%, the total acid content was 0.26 g·100 g^-1, the starch content was 1.05 g·100 g^-1 , the vitamin C content was 11.00 mg·100 g^-1 , the sucrose content was 4.80 g · 100 g^-1 , and the potassium content was 332.00 mg · 100 g^-1 . The growth period was 365 to 380 days. It could be planted in winter in Guangxi (October November) and harvested in November of the following year. Spring planting should be accomplished before mid to late February to avoid the impact of cold damage and harvesting can be done from January to February of the following year. The resistance to Fusarium wilt disease was evaluated through the pot and field experiments, and Guijiao No. 8 showed high resistance. The variety had been successfully planted in the main banana producing areas of Guangxi, such as Nanning, Yulin, Chongzuo, Beihai, and Baise, which could be suitable for planting in the tropical and subtropical regions such as Guangxi, Guangdong, Hainan, and Yunnan in China. The density of planting of 110 to 130 plants per mu should be recommended.