How did the "Salt Yellow Fragrant Rice" with an output of 505 kg per mu in saline-alkali land come about?

On October 27, the Institute of Genetics and Biology of the Chinese Academy of Sciences completed the actual harvesting and yield measurement of the new rice variety "Yanhuang Xiangjing" at the Dongying Experimental Base in Shandong Province, with an output of 505 kilograms per mu. The quality met the first-class standard of high-quality rice, providing a very important reference example for the cultivation of crops in saline-alkali land in my country.

News report on the successful yield measurement of Yanhuangxiangjing (Source: Shandong TV)

Although the yield of Yanhuangxiangjing seems insignificant compared to the more than 1,000 kilograms per mu of ordinary rice, this achievement is undoubtedly outstanding considering the saline-alkali land where it grows. After all, saline-alkali land belongs to medium- and low-yield paddy fields, and the high salt and alkaline environment in the soil seriously inhibits the growth of crops.

Land "incurable disease" is not easy to cure

Saline-alkali land refers to land containing saline soil and alkaline soil. Saline soil is salinized soil. The "salt" here is not the salt we eat everyday, but a compound formed by the neutralization of acid and alkali, mainly sulfate or chloride. Alkaline soil refers to alkaline soil containing heavy phosphate or carbonate.

The formation of saline-alkali land is the redistribution of soluble salts in the soil, and the salt content exceeds the normal value. Among them, the salt content in the soil is within 0.2‰, which is light saline-alkali land, between 0.2‰-0.4‰, which is moderate saline-alkali land, and more than 0.4‰, which is heavy saline-alkali land.

The reason why saline-alkali land was once called the "incurable disease" of land by experts is that in addition to having little organic matter and no fertility, making it difficult to promote seedling growth, it also brings osmotic stress, ion poisoning and other damages, causing crops to wilt or even die.

Therefore, in science, the two methods of saline-alkali land transformation and maintenance and the cultivation of salt-alkali tolerant varieties are usually combined to increase grain production capacity.

Severely saline-alkali land (source see watermark)

The first problem faced by saline-alkali land transformation and maintenance is the high cost. Saline-alkali land transformation mainly refers to the continuous improvement of land moisture, which can be achieved through salt drainage, salt washing, soil fertilization, etc.

Maintenance requires repeated watering, and some hard soils even need watering four or five times a year. The cost of transformation and maintenance per mu of land is as high as thousands or even tens of thousands of yuan.

From a cost perspective, researchers usually carry out partial transformation of saline-alkali land, such as draining and washing salt.

Compared with the transformation and maintenance of saline-alkali land, the cost of cultivating salt-alkali tolerant varieties is lower and the effect is more obvious. Crops that can survive in saline-alkali land must have the characteristics of salt tolerance, alkali tolerance, and disease resistance.

Rice is the country's main food crop. It is more tolerant to salt and alkali than other crops and is easier to mass produce. After years of repeated experiments and research by the Chinese Academy of Sciences research team, it was finally determined that the rice that can be used to measure the yield of saline-alkali land is Yanhuangxiangjing.

Complex breeding, obvious advantages

From the initial selection to the final version, the breeding process of Yanhuangxiangjing is quite complicated. The research team first used "Daohuaxiang No. 2" as the female parent and "Shennong 265" as the male parent for initial breeding. Then, in the process of breeding offspring, they introduced excellent genes of rice such as Haiyehong (salt-tolerant wild type) and Jinyuan E28 (a new hybrid of large-grained japonica rice). Finally, they used different concentrations of brackish water pressure irrigation to cultivate it. Yanhuangxiangjing, which was bred through complex breeding, has three obvious advantages.

The harvesting site of “Yanhuang Xiangjing” (Photo source: Institute of Genetics and Developmental Biology, Chinese Academy of Sciences)

First, it is more tolerant to salt and alkali, and saves more water. Yanhuangxiangjing can be planted in saline-alkali land with a salt content of 6‰, and irrigated with slightly saline water with a salt content of 3‰. As a water-saving rice variety suitable for the land, Yanhuangxiangjing requires about 400 cubic meters of fresh water per mu, which is one-third of the demand of ordinary rice. The low fresh water demand indicates that it is more tolerant to salt and alkali, and the difficulty of planting is relatively small.

Second, the growth period is more suitable for planting in saline-alkali land. Yanhuangxiangjing has a unique growth cycle, that is, it is sown in June and harvested in October every year. In this way, it can not only make full use of the light, temperature and precipitation resources from July to September, but also avoid the spring with high evaporation, low precipitation and severe salt return, and the cold and low temperature winter.

Third, the rice is of high quality and tastes better. The grains of salty yellow fragrant glutinous rice produced in Dongying are full and crystal clear. The main reason is that it contains few chalky grains, accounting for only 0.3‰ per grain. According to national regulations, the proportion of chalky grains in first-class high-quality rice is 10‰ (National Standard "Rice GB1354-2009"). From this aspect, salty yellow fragrant glutinous rice fully meets the conditions of high-quality rice.

"Yanhuang Xiangjing" high-quality rice (Source: Institute of Genetics and Developmental Biology, Chinese Academy of Sciences)

In addition, salty yellow fragrant rice contains sufficient flavor substances. Flavor substances are substances that cause comprehensive sensations in sensory organs, mainly in the mouth. The flavor substances in ordinary rice include phenols, aldehydes, alcohols and other compounds, with a number of more than 120. It is these compounds that determine the aroma of rice. The content of aromatic hydrocarbons, sterols and other flavor substances in salty yellow fragrant rice is half that of ordinary rice, so it naturally tastes better.

The country attaches great importance to it and the results are beginning to show

According to statistics, among the 1.5 billion mu of saline-alkali land in China, 550 million mu can be fully utilized. How to increase the grain output of these 550 million mu of saline-alkali land has always been a matter of great concern.

Chinese agricultural experts have been conducting experimental research on crop cultivation in saline-alkali land since the beginning of this century, and have made breakthrough progress in recent years. In 2018, the Institute of Genetics and Biology of the Chinese Academy of Sciences conducted research on salt-alkali tolerant crop breeding in the saline-alkali land of the Yellow River Delta, and co-established the Chinese Academy of Sciences Dongying Molecular Design Breeding Research Center with the Dongying Municipal Government.

In 2022, the research center concentrated on demonstrating new varieties of crops such as salt-tolerant soybeans, rice, corn, and long-spiked wheat, with an experimental area of ​​1,500 acres; in the same year, it organized an international conference on saline-alkali land seed industry innovation, which effectively improved the theoretical research level of saline-alkali land cultivation in my country.

Group photo of the staff of the “Yanhuang Xiangjing” yield measurement meeting (Source: Official website of the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences)

As a pioneer crop in saline-alkali land, rice has been given great attention in saline-alkali land planting experiments and research. In June this year, the Institute of Genetics and Biology of the Chinese Academy of Sciences planted salty yellow fragrant rice in 200 mu of saline-alkali land in Dongying, Shandong.

Starting from July, researchers first used fresh water to promote the emergence of rice seedlings, and then used slightly brackish water with a salt content of 2.5‰ to 3.5‰ until the rice matured and was harvested in early October. The actual harvest and yield of the salt yellow fragrant glutinous rice not only became a powerful example of the promotion of rice cultivation in saline-alkali land, but also had important significance for ensuring the country's food security. It is understandable that it has attracted widespread attention.

Author: Wei Deyong, member of Shenzhen Writers Association, Guangdong

【References】

1. Dazhong Daily, December 7, 2021, p. 3

2. Paper "Rice Planting and Utilization of Saline-Alkali Land and Protection of Black Soil", author Chen Wenfu

3. Article "Rice Planting Technology in Saline-Alkali Land", Sannonglu official website.

4. The paper "Formation of saline-alkali land and salt tolerance of plants", author Chen Kong

END

Editor: Muzi