Media: Yield loss and total crop failure not the fault of super rice; rice blast epidemic is the trigger
[Finance Exclusive]Yield loss and total crop failure: the fault is not with super rice
The event half a year ago in Anhui, where ten thousand mu of super rice suffered yield loss and total crop failure, triggered strong public attention to super rice. However, according to a reporter from Caijing, in this event, the local rice blast epidemic was the trigger, and the yield loss and total crop failure were directly related to poor farmer management
By | Caijing reporter He Tao
The event half a year ago in Anhui, where ten thousand mu of super rice suffered yield loss and total crop failure, triggered strong public attention to super rice. In October 2014, parts of Anhui experienced rice yield loss or even total crop failure, with affected area exceeding ten thousand mu. The rice seed involved was the super rice “Liangyou 0293”, from Yuan Longping High-Tech Agriculture Co., Ltd. (hereinafter referred to as Longping High-Tech).
After the incident, the Seed Management Station under the Anhui Provincial Agricultural Committee petitioned the Ministry of Agriculture, hoping that the province would no longer be included in the planting areas for “Liangyou 0293”. As a result, public opinion began to extend to doubts about super rice.
However, according to a reporter from Caijing, in this event, the local rice blast epidemic was the trigger, but even if rice blast struck, “if pest and disease control were strengthened at every stage, there would be no problem.” Luo Xuefu, deputy director of the Guangxi Yulin Agricultural Technology Promotion Station, told a Caijing reporter that Guangxi is a high-incidence area for rice blast, and based on experience, yield loss and total crop failure are directly related to poor farmer management.
“Rice blast” is the “cancer” of rice. It mostly occurs after rice heading, drying up the neck of the panicle and blocking nutrient transport; if pesticide is not sprayed in time, large areas wither and dry up. In rice regions north and south of China, rice blast occurs to varying degrees every year. In epidemic years, severely affected areas generally suffer 10%-20% yield loss, with severe cases reaching 40%-50%, and some fields even producing no harvest at all.
The “Liangyou 0293” variety indeed cannot withstand rice blast. The variety's greatest advantage is resistance to lodging, but it is “moderately susceptible to bacterial leaf blight and highly susceptible to rice blast.” Anhui is not a high-incidence area for rice blast, so it was listed as a suitable planting region for “Liangyou 0293”. Jiangsu, also a suitable planting region, likewise experienced large-area total crop failure due to rice blast in 2012.
In fact, due to biological adaptation, the advantage of a hybrid variety generally lasts only from several years to several decades, so hybrid rice varieties on the market need constant renewal. The “Liangyou 0293” rice produced by Longping High-Tech passed national approval in 2006 and had already been planted in Anhui for as long as 8 years. Usually a new variety is popular for only two or three years; if it is popular for 10 years, it counts as a very good variety. At present, China's super rice 100-mu plot program has completed the fourth-phase 1000 kg target, and super rice variety renewal has also entered the “fourth generation.” “Liangyou 0293” is an old variety bred during the second-phase program of super rice.
“Liangyou 0293” was not the only variety that suffered yield loss. According to a report by Agricultural Materials Herald, in 2014, not only in Anhui but also in Hubei, Henan, Jiangsu and many other places, many rice varieties suffered yield loss due to climate problems.
In addition, the factor of the single variety “Liangyou 0293” cannot represent the entire population of super rice varieties, and extending it into doubt about super rice as a whole is even more absurd. However, the call to reflect on super rice “valuing yield over quality” has some merit, namely that the direction of super rice research and development indeed placed too much emphasis on high yield and did not give sufficient attention to indicators such as stable yield and stress resistance.
The concept of “super rice” was proposed by the International Rice Research Institute. Breeders there began selecting and breeding new super-high-yield plant-type rice in 1989. Its main characteristics are few tillers, large panicles, erect and dark green leaves, and thick, sturdy, lodging-resistant stems. It can be said that from the very beginning of the concept, super rice was aimed at super high yield. In 1994, the International Rice Research Institute bred the first case of “super rice,” whose yield in tropical dry-season small-plot trials could reach 833 kg/mu. However, this kind of super rice also showed drawbacks such as low seed-setting rate, poor grain filling, and weak resistance to pests and diseases.
Nevertheless, this astonishing yield stimulated China's ambition to develop super-high-yield rice breeding. In 1996, the Ministry of Agriculture formally established the project and began a 10-year “China Super Rice” breeding program. Thereafter, the research team represented by Yuan Longping continuously broke records for super-high-yield rice breeding. In October 2014, “Y Liangyou 900” super rice set a record in Huaihua, Hunan, with an average yield of 1026.7 kg per mu.
From the perspective of agricultural science, this record is very difficult to promote and replicate on a large scale. Behind the super-high-yield figures of super rice is the planting of excellent varieties in excellent fields by researchers, combined with scientific cultivation and management; none of these can be missing. Newly bred super rice varieties will show very high yields in experimental demonstration fields, but at the level of large-area planting, the yield-increasing effect shrinks. However, this does not affect the important significance of super rice to China's grain yield increase. In terms of unit yield, China's actual average rice yield per mu reached 447.8 kg in 2013, and super rice played an indispensable role.
It should also be noted that the momentum of hybrid rice yield growth has slowed considerably. The average yield per mu of hybrid rice increased by 127 kg over the 12 years from 1976 to 1988. But over the following more than 20 years, it increased by only about 110 kg, and to date the average yield per mu is 550 kg.
Obviously, the cost-effectiveness of research and development that simply increases rice yield is continuously declining. Wan Xiangyuan, general manager of Beijing Jinguanfeng Biotechnology Co., Ltd., analyzed for a Caijing reporter, “We should not simply pursue absolute high yield, but should pursue relative stable yield while achieving high yield.” Multinational seed companies are very shrewd in this regard, that is, they emphasize strengthening the stress resistance of seeds so that seeds can grow under different environmental conditions, such as drought resistance, pest and disease resistance, and broad adaptability.
In the national variety approval process, resistance has only been taken seriously in recent years; previously only yield was emphasized. In the future, a superior variety must be premised on suitable stress resistance and broad adaptability, and must be able to show stable yield under climate and environmental changes in different years and in different geographical environments.