How can super rice achieve a yield of over 1,000 kg per mu?

After expert yield measurement organized by the Ministry of Agriculture, the fourth-phase China super rice project targeting a yield of 1,000 kg per mu in Xupu County, Hunan Province, supported by the Ministry of Agriculture and led by Academician Yuan Longping, achieved a major breakthrough, with a 100-mu plot setting a new record of 1,026.7 kg per mu. On the same day, Minister of Agriculture Han Changfu sent a congratulatory letter to Academician Yuan Longping, expressing warm congratulations and sincere greetings. Han Changfu said this was the result of the joint efforts and long-term struggle of Yuan Longping and a large number of agricultural science and technology workers, and a tremendous contribution to China's and the world's agricultural science and technology cause.

In his congratulatory letter, Han Changfu said that super rice exceeding 1,000 kg per mu not only marks that China's hybrid rice research has once again reached the world's pinnacle, demonstrating that the Chinese people have the ability and confidence to rely on their own strength to solve the country's food security problem, but will also have an important and far-reaching impact on safeguarding global food security.

Why can super rice achieve over 1,000 kg per mu?

On April 28, 2013, General Secretary Xi Jinping discussed the “Chinese Dream” with national model workers. At that time, Yuan Longping took out two photos of super hybrid rice and handed them to the General Secretary, saying: “I have two dreams, one is the ‘dream of enjoying the cool beneath the rice plants’, and the other is the dream of hybrid rice covering the globe. This is my Chinese Dream.” Less than a year later, the “father of hybrid rice” Yuan Longping once again delivered a satisfactory answer.

“High-yield rice requires the ‘four goods’ to be matched: good seed, good method, good field, and good ecology. Among them, good seed is the core, good method is the means, good field is the foundation, and good ecology means good climate and ecological conditions.”

Yuan Longping, now in his “post-80s”, is already envisioning the “post-90s” goal: in the future, rice yields per mu still have 500 kg of potential awaiting researchers to tackle, and with advances in breeding technology and other integrated technologies, super rice yields per mu could even reach 1,500 kg.

What does it mean for super rice to break through a yield of over 1,000 kg per mu?

On October 10, 2014, an expert group dispatched by the Ministry of Agriculture conducted on-site yield measurement and acceptance of the super hybrid rice “Y Liangyou 900” in Hongxing Village, Hengbanqiao Township, Xupu County, Hunan Province. Through random sampling, the average yield per mu was measured at 1,026.70 kg, marking the success of the fourth-phase 1,000 kg per mu breakthrough of China's super hybrid rice led by the “father of hybrid rice” Yuan Longping, and also marking that China's hybrid rice breeding technology has reached a new level, with positive significance for China's food security.

From the first-phase target of 700 kg per mu in 2000, the second phase of 800 kg per mu in 2004, the third phase of 926.6 kg per mu in 2011, to 1,026.70 kg per mu in 2014, China's hybrid rice breeding research achieved a world-renowned “four consecutive jumps” in 14 years.

Why is super rice so “super”?

After tasting super hybrid rice, Yuan Longping believed that the grains were round and plump, with a rich oily luster. When it entered the mouth, the rice was delicate and fragrant, full of elasticity, with an excellent taste.

In addition to increasing yield, the new super hybrid rice Y Liangyou 2 will place more emphasis on rice nutrition. The research team is working to add vitamin A, protein, starch and other nutrients to new varieties, in hopes of reducing anemia and visual disorders.

Does super rice have any defects?

Cheng Shihua: Super rice is hybridized from japonica rice and indica rice, like a mixed-race child, and the differences between the parents are very large, so problems with poor late-stage functionality are very likely to appear.

Yuan Longping: Super hybrid rice cannot be saved as seed, and the amount of fertilizer used is relatively large.

What is the theoretical limit of rice yield per unit area over a relatively large area?

The breeding of super hybrid rice in China has always followed the technical route proposed by Academician Yuan Longping: namely, morphological improvement and utilization of heterosis.

Academician Yuan Longping also stated that according to estimates by Japanese scholars, the light energy utilization rate of rice, that is, the ratio of the energy contained in organic matter accumulated by crop photosynthesis to the solar energy irradiated on that ground surface, can reach about 5% at most. If we are more conservative and halve this figure, calculating only at a light energy utilization rate of 2.5%, taking the solar radiation in the Changsha area as an example, theoretically the yield per mu of early rice can reach 1,000 kg, the yield per mu of late rice can reach 1,100 kg, and the yield per mu of middle rice can reach 1,500 kg.

“Y Liangyou 900” is a middle rice variety, and there is still 500 kg of potential to reach its theoretical yield.

What varieties of super rice are there?

Over the past 20 years, the promotion of major rice varieties has shown a marked increase in the number of varieties, a significant decline in the average annual promotion area of a single variety, a narrow promotion region for conventional rice, a broad promotion region for hybrid rice, a decrease in the number of broadly promoted varieties, and rapid development of two-line hybrid rice.

Upper Yangtze River rice region. In the past 10 years, the varieties with relatively large promotion and application areas in this rice region include II You 838——a high-yield, stable-yield, broadly adaptable variety, and Gangyou 22——a medium-late maturing, large-panicle hybrid middle indica.

Middle and lower Yangtze River rice region. In the past 10 years, the varieties with relatively large promotion and application areas in this rice region include Shanyou 63——the hybrid rice variety with the longest promotion time and the largest application area, Liangyoupeijiu——a representative variety of the first generation of two-line hybrid rice, Jinyou 207——an early-maturing, high-quality hybrid late indica variety, Fengliangyou No. 1——a high-quality two-line hybrid rice variety, Xinliangyou No. 6——an early-maturing, high-quality two-line hybrid rice variety, Y Liangyou No. 1——a new high-yield, high-quality two-line hybrid rice variety, Tianyou Huazhan......

What work has the Ministry of Agriculture done in super rice research and promotion?

On April 9, 2014, Minister of Agriculture Han Changfu came to the Hainan Nanfan Base of the National Hybrid Engineering Technology Research Center, and together with the father of hybrid rice Yuan Longping announced the launch of the fourth-phase super hybrid rice research, striving to breed new super rice varieties with a yield potential of over 1,000 kg per mu within 5 to 8 years. Han Changfu said the Ministry of Agriculture will vigorously support the fourth-phase super hybrid rice research, so that super rice yields per mu can reach a higher level.

After attending the Boao Forum for Asia agricultural roundtable with the theme of “food security”, Han Changfu rushed to the Nanfan Base to investigate the super rice breeding research site led by Yuan Longping, and to discuss rice scientific research and industrial development strategies with Yuan Longping. Accompanied by Yuan Longping, Han Changfu walked into the experimental field to inspect the growth of new super hybrid rice varieties that had entered the maturity stage. Under the blazing sun, the golden rice ears bowed their heavy heads, presenting a scene of an imminent bumper harvest.

In response to the impact caused by the transition from traditional agriculture to modern agriculture, how can hybrid rice be saved?

In recent years, the downward trend in hybrid rice varieties has been very obvious. The number of varieties with an annual promotion area of over 1 million mu increased from 46 in 2002 to a peak of 59 in 2004, then declined year by year to 29 in 2012; the number of varieties with an annual promotion area of over 5 million mu dropped from about 9 in the early period to 1 per year at present; since 2007, no variety with over 10 million mu has appeared. The average annual promotion area of a single major hybrid rice variety fell sharply from 2.133 million mu in 1993 to 374,000 mu in 2012, a drop of 82.5%.

“Save hybrid rice!” was the proposal heard most frequently by reporters on August 26 at the “C Liangyou Huazhan” upper Yangtze River variety demonstration meeting. In fact, as early as three years earlier, Professor Chen Liyun of Hunan Agricultural University had already issued a call to save hybrid rice: saving hybrid rice should be treated as a major matter for solving China's food security and rescuing the national seed industry.