Fruit fusion: how will the market react to Chinese scientists’ lychee-longan creation?

Chinese scientists who crossed a lychee with a longan are preparing to test its market release after the first substantial harvest of the high-yield, cold-resistant fruit is expected to ripen next month.

The new variety, named “Cuimi”, was bred using the Shixia longan – a popular cultivar in Guangdong province – as its maternal parent and a lychee as its paternal parent, according to the research team. The hybrid fruit breaks long-standing reproductive barriers between plant genera.

It has been planted across Guangdong, Sichuan and Yunnan provinces in southern China, with its yield this year reaching several thousand jin, a Chinese unit equal to 500 grams or 17.6 ounces. Trial sales are scheduled for mid-September.

Speaking at an on-site demonstration hosted by South China Agricultural University (SCAU) in Guangzhou on August 9, Liu Chengming, a professor at the university’s College of Horticulture and the lead developer of the variety, told media that about 90 per cent of Cuimi’s genetic material comes from its mother. Consequently, its appearance and flavour lean closer to those of the longan.

Nevertheless, the hybrid has inherited several key traits from its father, including the cracked, textured skin characteristic of lychees, according to the team which said its flesh was tender, crisp and free of fibrous strands.

Compared with the Shixia longan, Cuimi delivered about double the yield, was more cold resistant and ripened 15 to 20 days later, the researchers said.

According to Liu, these characteristics could help expand longan cultivation areas in China while extending the fruit’s commercial selling season.

“The creation of Cuimi is significant for its breakthrough in intergeneric hybridisation, long regarded as a major technical obstacle,” the state-run newspaper Science and Technology Daily said on Monday.

“The achievement has expanded the techniques available for crossbreeding fruit trees in China and could serve as a model for developing new varieties of other fruits.”

Lychees and longans share a strong reproductive barrier, making crossbreeding them an exceptionally difficult challenge.

Liu’s team at SCAU set out to overcome this hurdle in 2007. After nearly three years of research, they developed a pollination technique that allowed longan flowers to be fertilised by lychee pollen. However, even with this breakthrough, the success rate was a mere 0.3 per cent.

Applying the method, researchers pollinated more than 100,000 female flowers to ultimately harvest around 300 hybrid seeds.

The team then identified 69 genuine hybrids before selecting the single strongest plant – code-named SZ52 – for its superior quality, flavour, and late ripening. It formally passed Guangdong’s official variety approval process in 2022.

The researchers then faced another hurdle: enabling the plant to withstand extreme winter cold. Last year, through refined cultivation techniques, researchers eliminated frost damage.

At an experimental cultivation base in Lianzhou, a county-level city in Guangdong where winter temperatures drop as low as minus 3 degrees Celsius (26.6 degrees Fahrenheit) to minus 7 degrees, the new variety survived the cold. Its first substantial harvest is expected to ripen in early to mid-September.

Next year, Cuimi’s total yield is projected to exceed 25,000kg (55,100 lbs), according to its developer. Liu noted that the fruit should become more affordable between August and October next year as it reaches a broader array of retail and online shopping platforms.

His team is developing another hybrid using lychee as the female parent and Shixia longan as the male parent, alongside other crosses aimed at combining superior traits including enhanced disease resistance and higher yields.

Driven by a major national push to bolster independent research and development in the seed sector, domestic Chinese crop and livestock varieties have been steadily expanding their market share.

“For some varieties where China’s breeding level used to be relatively low, not only have we developed our own varieties in recent years, but their market share has also increased rapidly,” said Zhang Xingwang, vice-minister of agriculture and rural affairs, during a press conference in January.