Hybrid rice researcher Yuan Longping told President Xi Jinping on Sunday that he hopes his hybrid rice will one day be grown throughout the world.

The elderly Yuan met Xi at the headquarters of the All-China Federation of Trade Unions, where Xi also met with recipients of the "Model Workers" title just ahead of International Workers' Day, which falls on May 1.

Yuan recently began the fourth phase of a hybrid rice breeding experiment, targeting a yield of 1,000 kg of rice per mu (0.0667 hectares).

Yuan said exports of hybrid rice should be permitted and seed companies should get greater support so as to expand the rice's global reach.

Xi previously met Yuan in 1998, when Xi was in charge of agricultural work in east China's Fujian Province. Research on hybrid rice began in 1996 as part of government efforts to ensure food security.

Xi also chatted with other model workers, including an aerospace scientist, a village chief, a steel company employee and the country's first female tractor driver.

Chang Guoli, the head of a research team at Weichai Power, an automobile and machinery company in east China's Shandong Province, is one of the model workers. Her work includes testing engines in high-altitude regions and places with extreme weather.

Xi said skin care products and other protective measures should be used to protect Chang and her female colleagues from sunburns.

Xi also showed concerned about the health of Guo Mingyi, a 54-year-old iron mine worker who was honored for his contributions to needy families.

Guo has spent half of his salary in recent years to pay for schooling for 180 needy children. He has also donated blood regularly for the last 20 years.

"As frequently as you donate blood, can that compromise your health?" Xi asked Guo. "Take care of your health."

"Happiness does not fall out of the blue and dreams will not come true by themselves. We need to be down-to-earth and work hard," Xi said.

He also called on society and the public to respect workers and their work.

"We should uphold the idea that working hard is the most honorable, noblest, greatest and most beautiful virtue," he said.

Xi pledged to protect the rights and interests of workers and ensure social justice so that all workers can live a dignified life.