Yuan might have been one of the very early Chinese geneticists who was influenced by modern genetics. He attached great importance to the application of molecular biology to improve the efficiency of rice breeding and participated in the Chinese rice genome sequencing project. As recently as ~20 years ago, Chinese rice scientists discovered that only 466 Mb of the rice genome contained rich genetic variations, with 46,022–55,615 protein-coding genes (Yu et al., 2002). In 2018, a number of institutions from China jointly released the world’s first, nearly complete, and high-quality pan-genome of Asian cultivated rice (Wang et al., 2018b). This research resulted in the renaming of indica and japonica rice, and provided the most refined cultivated rice populations, which contain a wealth of genomic structural variants (SVs). Recently, based on the genome information of two indica rice varieties, ZS97 and MH63, Chinese scientists discovered a large number of SVs at the end of the long arm of chromosome 11, located in the centromeric region, and a large number of resistance genes, which was the first reported gap-free plant reference genome (Song et al., 2021).

Every year, billions of people suffer from undernourishment worldwide. In 2019, approximately 3 billion people worldwide did not have access to a healthy diet; worse, 22.0% of children under the age of five (149.2 million children) were stunted due to malnutrition, which is particularly pervasive in many developing countries in Africa and Asia (FAO et al., 2021). The Rockefeller Foundation proposed a rice breeding program to increase the beta-carotene content in “Golden Rice” in 1982. However, public misperceptions caused by false non-governmental organization (NGO) narratives have resulted in only a very few countries approving “Golden Rice” for cultivation and commercial production (Qaim, 2020). Chinese geneticist Liu Yaoguang used synthetic biology and a multi-gene stacking system to develop “purple endosperm rice”, which is rich in anthocyanins in the light purple endosperm and has enhanced nutrition (Zhu et al., 2017). Anthocyanins have excellent anti-aging effects and while they are found in many grains, they are naturally only present in the seed coat and not in the endosperm. In addition to developing rice with high anthocyanin content, astaxanthin-containing rice has been produced in the laboratory through genetic engineering and synthetic biology (Zhu et al., 2018). Astaxanthin is an orange-red carotenoid pigment generally produced by some algae and bacteria, but most land plants cannot synthesize it. The pigment is the highest-graded carotenoid and one of the strongest antioxidants discovered to date; astaxanthin exhibits strong free radical scavenging ability, anti-aging properties, and protective effects against cardiovascular disease. Therefore, large-scale promotion of the cultivation of “purple endosperm rice” has great beneficial potential for eliminating malnutrition on a global scale and improving human health.

Cultivated rice is diploid, a cultivated species that has been domesticated from its diploid ancestor over thousands of years. However, in addition to diploid cultivated rice, the Oryza genus includes 25 other wild plants, which can be classified into 11 categories according to their genome characteristics, including 6 types of diploid genomes and 5 types of tetraploid genomes. Among these, the allotetraploid wild variety combines the two complete diploid chromosomes of the CC and DD genomes, which have natural heterosis and also the advantages of large biomass and strong environmental adaptability. Chinese geneticist Li Jiayang proposed a rapid de novo domestication strategy for allotetraploid wild relatives to reduce their domestication time, which typically requires thousands of years. The research team identified a high-quality allotetraploid polyploid rice 1 (PPR1) wild relative that originated from tropical regions of South America with an extremely large biomass; the plant height can reach 2.7 m, the ear length can reach 48 cm, and the leaf width can reach 5 cm. The researchers assembled the first allotetraploid rice reference genome with a size of 894.6 Mb, which is about twice the size of cultivated rice. More than 81,000 high-confidence genes were annotated, including 10 domesticated-related genes and 113 important agronomic trait genes found in cultivated rice. Through gene editing of these genes, rapid domestication has been achieved (Yu et al., 2021). This study is the first to demonstrate de novo domestication of a wild crop and indicates that de novo domestication may facilitate cultivation of a new staple food crop (Zhu and Zhu, 2021).

Traditional cultivated rice is an annual crop, which means that seeds need to be sown every year. Scientists from Yunnan University have cultivated a perennial rice, through traditional hybridization of O. sativa L. and O. longistaminata which was rice variety native to Niger. After one-time planting, a crop can be harvested for the next 3–5 years (Zhang et al., 2019), greatly improving planting efficiency, and saving seed, fertilizer, and labor. Recent data has shown that the average yield of summer rice in July is 655.65 kg/mu, the average yield of autumn rice in October is 464.8 kg kg/mu, and the average yield of perennial rice is 1120.45 kg/mu. Thus, perennial rice has significant potential for large-scale planting. In a study on the combined effects of nitrogen application and planting density for four consecutive harvest seasons, researchers found that perennial rice maintained the best regrowth ability at a higher planting density, and lower level of nitrogen fertilizer. This suggests that perennial rice has the potential to use less chemical fertilizer while still producing high yields, which is conducive to green and sustainable agriculture (Zhang et al., 2021). Importantly, the profit for farmers from planting perennial rice currently averages at about 235% higher than that from planting annual rice (Zhang et al., 2021). In addition, owing to the reduction in plowing of perennial rice fields, soil erosion can be reduced, protecting arable land (Huang et al., 2018), and potentially promoting the accumulation of soil organic carbon, mitigating climate change. The commercialized rice was successfully grown on more than 15,000 ha by ~45,000 smallholder farmers in southern China in 2021, contributing to crop productivity, farmer livelihoods, and soil health (Zhang et al., 2022). By leveraging wild rice relatives, perennial rice’s success is inspiring for other crops’ breeding and social, economic, and environmental sustainability (Crews and Cattani, 2018; DeHaan et al., 2020; Zhang et al., 2022).

The team led by Yuan Longping has a great ambition in promoting sea rice. By leveraging saline-alkali land improvement projects supported by the central government, the team plans to plant sea rice in 100 million mu in 8–10 years. Due to the accelerated biotechnology advancements in rice research (Chen et al., 2022; Shang et al., 2022), there is a great potential for large-scale improvement in its production along the Chinese seashore. Currently, fields in Panjin exhibit an average yield of only 300 kg/mu, half that of traditional rice fields. A breakthrough in sea rice technology could facilitate turning at least 300 million mu of saline-alkali land into grain fields, which is equivalent to 1/6 of China’s arable land. A recent study on rice salt stress showed that the gene RST1 (rice salt tolerant 1), a negative regulator played a crucial role in rice survival under saline conditions (Deng et al., 2022). Malfunction of RST1 promotes nitrogen utilization and reduces NH 4 + accumulation subjected to salt stress, and, increases grain yield, which laid a solid foundation in sea-water tolerant rice breeding (Deng et al., 2022).

During the entire growth period of rice, the plant is susceptible to infection by various pathogens. Rice blast, also called rice cancer, is caused by the fungus Magnaporthe oryzae; it has the greatest impact on yield causing a 10–35% reduction in yield or even no harvest (Li et al., 2019). Identifying resistance genes in rice to M. oryzae, especially long-lasting broad-spectrum resistance genes, has been a long and difficult task for rice breeders. Recently, researchers discovered a key role for Ideal Plant Architecture 1 (IPA1), a key transcription factor for the establishment of ideal plant types in rice, in combatting rice blast disease (Wang et al., 2018a). Interestingly, IPA1 promotes growth under normal conditions, and improves the immune response when a plant is infected by the fungus, providing an important theoretical basis for high-yield and high-resistance breeding. Through the combination of big data analysis in genetic, biochemical, pathological, and other experimental methods, researchers have discovered the gene bsr-d1, which confers broad-spectrum and long-lasting disease resistance to rice blast caused by M. oryzae (Li et al., 2017). The researchers also discovered a recessive gene, bsr-k1, which also confers broad-spectrum resistance to rice blast (M. oryzae), as well as to bacterial blight, caused by the proteobacteria Xanthomonas oryzae. The immune response activated by bsr-k1 is relatively mild and has no significant effect on the agronomic traits of rice (Zhou et al., 2018). Every year, China loses at least 16 million tons of food due to pathogens and insect pests, which is equivalent to feeding 300 million people annually (Deng et al., 2021). Therefore, the discovery of these transcription factors and disease resistance genes indicates that pathogen resistance of rice may be improved through gene editing in the future (Deng et al., 2017; Gao et al., 2021), which is extremely important for obtaining a stable rice yield.

In the 1960s, Green Revolution, the large-scale promotion of semi-dwarf rice and wheat varieties, effectively solved the problems of plant lodging and yield reduction caused by large-scale fertilization, and greatly increased the output of the world’s major food crops (Evans and Lawson, 2020). Although the semi-dwarf varieties developed as part of the Green Revolution have excellent characteristics of high fertilizer tolerance, lodging resistance, and high yield, they also have the disadvantage of low nitrogen use efficiency, which leads to a high dependence on chemical fertilizers (Li et al., 2018). To increase crop yields, and continuous application of a large amount of nitrogen fertilizer is required, but this not only increases planting costs but also leads to increasingly serious environmental problems. Chinese rice scientists have recently discovered that rice GROWTH-REGULATING FACTOR 4 (GRF4) is a positive regulator of plant carbon-nitrogen metabolism; it also promotes and integrates plant nitrogen metabolism, photosynthesis, and growth. GRF4 can also interact with the rice growth inhibitor DELLA protein; the accumulation of DELLA protein led to the first Green Revolution. By tilting the balance of GRF4-DELLA to increase the abundance of GRF4, it is possible to increase the nitrogen use efficiency of Green Revolution varieties and increase grain yield, while maintaining the excellent traits of semi-dwarfing. Similarly, researchers recently discovered another key gene, NITROGEN-MEDIATED TILLER GROWTH RESPONSE 5 (NGR5) (Wu et al., 2020), which controls the efficiency of nitrogen use in rice. Researchers have confirmed that NGR5 is a positive regulator of rice growth and development (plant height, tiller, and number of grains per panicle) in response to nitrogen. In the current rice varieties, increasing the expression of NGR5 improves nitrogen use efficiency and maintains the semi-dwarfing and high-yield characteristics, ultimately leading to higher rice yields under appropriately reduced nitrogen fertilizer conditions. The discovery of GFR4 and NGR5 genes is expected to lead to the production of new green and high-yield rice varieties.