Every winter, like many seniors in Northeast China, Li Yanhua travels more than 4,000 kilometers from Hailun city, Heilongjiang, to Sanya in the nation's southernmost province of Hainan.

However, Li spends winter in Sanya not to escape the bitter cold of the northeast, but to cultivate new soybean varieties with her team at the Sanya Nanfan Scientific and Research Breeding Base.

Over the past 32 years, the 57-year-old soybean expert and researcher at the Chinese Academy of Sciences' Northeast Institute of Geography and Agroecology in Hailun, has selected and cultivated 17 high-yield and high-quality varieties of the Dongsheng soybean.

These varieties, which are rich in oil and protein, are now planted on more than 3.3 million hectares of farmland in Northeast China, helping to increase grain yield by 1 billion kilograms and local economic benefits by 4 billion yuan.

"The process for new soybean varieties, from breeding to approval, usually takes 10 to 12 years," Li said. "To shorten this period, almost every year after the autumn harvest, I take seeds to Hainan for planting. I return to Heilongjiang for further experiments after the seeds are harvested the following spring, which helps add one or two growing seasons and shortens the breeding time."

In 1990, after graduating in crop science at Northeast Agricultural University in Harbin, capital of Heilongjiang, Li returned to her hometown and became a member of the Northeast Institute of Geography and Agroecology.

"I was born to a rural family that had grown soybeans for generations. I was very familiar with the crop, but never imagined that I would spend most of my life researching it," she said.

On her first day at the institute, Li set a goal of cultivating high-quality soybean varieties suitable for planting and processing in cold climates.

Every year, she makes more than 300 soybean hybrid combinations and cultivates them in an experimental field.

"As the flowering period for soybeans is short, and the ideal hours for hybridization experiments are only from 4 am to 10 am, I usually arrive at the experimental field before 4 am during the flowering time," Li said.

Unlike farmers who stand to benefit from a higher degree of mechanization, Li's soybean hybridization experiment requires artificial harvesting, threshing and classification.

At harvest time, she usually remains sitting on the ground for several hours to select and sort soybeans.

To benefit more farmers with her professional knowledge, Li set up several WeChat groups to offer consultation services and help the farmers solve problems.

She has lectured at hundreds of technical training courses at night schools and in fields for farmers, attracting thousands of local agriculturists.

In recent decades, Li has received many awards, and in 2017, she was selected as a Key Technical Talent of the Chinese Academy of Sciences for her achievements in solving crucial technical problems and promoting technological innovation.

As China's major grain production area, Heilongjiang is home to the nation's largest soybean-producing zone.

Last year, more than 4.9 million hectares of land in the province was used to plant soybeans, accounting for 48.1 percent of the national total, with local production of the crop reaching 9.53 million tons, or 47 percent of the national total.

"Soybeans have been cultivated for about 5,000 years, so we should develop the best seeds to improve our efficiency," Li said.