Improving soil quality while achieving higher productivity is the major challenge in the agricultural industry.  Wheat (Triticum aestivum L.)–maize (Zea mays L.) (W–M) rotation is the dominant planting pattern in the Huang-Huai-Hai  Plain and is important for food security in China.  However, the soil quality is deteriorating due to the W–M rotation’s long-term, intensive, and continuous cultivation.  Introducing legumes into the W–M rotation system may be an effective way to improve soil quality.  In this study, we aimed to verify this hypothesis by exploring efficient planting systems (wheat–peanut (Arachis hypogaea L.) (W–P) rotation and wheat rotated with maize and peanut intercropping (W–M/P)) to achieve higher agricultural production in the Huang-Huai-Hai   Plain.  Using traditional W–M rotation as the control, we evaluated crop productivity, net returns, soil microorganisms (SMs), and soil organic carbon (SOC) fractions for three consecutive years.  The results indicated that wheat yields were significantly increased under W–P and W–M/P (382.5–579.0 and 179.8–513.1 kg ha⁻¹, respectively) compared with W–M.  W–P

and W–M/P provided significantly higher net returns (58.2 and 70.4%, respectively) than W–M.  W–M/P and W–M retained the SOC stock more efficiently than W–P, increasing by 25.46–31.03 and 14.47–27.64%, respectively, in the 0–20 cm soil layer.  Compared with W–M, W–M/P improved labile carbon fractions; the sensitivity index of potentially mineralizable carbon, microbial biomass carbon (MBC), and dissolved organic carbon was 31.5, 96.5–157.2, and 17.8% in 20–40, 10–40, and 10–20 cm soil layers, respectively.  The bacterial community composition and bacteria function were altered as per the soil depth and planting pattern.  W–M/P and W–M exhibited similar bacterial community composition and function in 0–20 and 20–40 cm soil layers.  Compared with W–P, a higher abundance of functional genes, namely, contains mobile elements and stress-tolerant, and a lower abundance of genes, namely, potentially pathogenic, were observed in the 10–20 cm soil layer of W–M and the 0–20 cm soil layer of W–M/P.  SOC and MBC were the main factors affecting soil bacterial communities, positively correlated with Sphingomonadales and Gemmatimonadales and negatively correlated with Blastocatellales.  Organic input was the main factor affecting SOC and SMs, which exhibited feedback effects on crop productivity.  In summary, W–M/P improved productivity, net returns, and SOC pool compared with traditional W–M rotation systems, and it is recommended that plant–soil–microbial interactions be considered while designing high-yield cropping systems.

China has the most people with diabetes in the world (IDF 2021), and the promotion of a healthy diet is a key public health priority for controlling the prevalence of diabetes in China (Hu 2011).  Rice (mainly white rice) is a staple food for more than 60% of the Chinese population (Hu and Sheng 2021).  Because white rice has the husk, bran, and embryo completely removed during the milling process, it is low in the dietary fiber, micronutrients, and polyphenols that are conducive to glucose metabolism (Aryaeian et al. 2017; McRae et al. 2018; Barra et al. 2021).  In addition, white rice is high in carbohydrates (starch) and generally has a high glycemic index (GI) (Atkinson et al. 2021), meaning that consumption in large amounts may cause high postprandial levels of blood glucose and insulin, and consequently reduce insulin sensitivity and pancreatic β-cell function (Livesey et al. 2019).  These factors suggest that a higher consumption of white rice may increase the risk of diabetes.

Another rice trait that may lead to a high risk of diabetes associated with high white rice consumption is related to arsenic exposure.  Compared to other cereal crops such as wheat and barley, rice is more efficient in the uptake and translocation of arsenic (Su et al. 2010), which is widely distributed in soil, water, and air and is highly toxic in its inorganic form (Chung et al. 2014).  White rice has an inorganic arsenic (iAs) content more than 10 times higher than other cereals (TatahMentan et al. 2020).  iAs exposure has been shown to increase insulin resistance and reduce pancreatic β-cell function by increasing cytokine levels, inhibiting proliferative-activated receptors, inducing oxidative stress, activating nuclear factor Kappa B, and increasing amyloid formation in the pancreas (Bell 2015).  A positive dose-response relationship between the risk of diabetes and the amount of iAs exposure has been also found; namely, the risk of diabetes increases by 13% for each 100 µg L^–1 increase of iAs in drinking water (Wang et al. 2014).  Based on the average daily rice (mainly white rice) consumption rate per capita (210 g; OECD-FAO 2022), the recommended daily water intake rate (1.5–1.7 L; CNS 2022), and the average iAs content in white rice (103 µg kg^–1; Li et al. 2011) in China, the estimated daily consumption of iAs in white rice is equivalent to 12.7–14.4 μg L^–1 of iAs in drinking water, so the risk of diabetes increases by 1.7–1.9% due to iAs exposure from white rice consumption in China.

Several studies have investigated the association of diabetes risk with white rice consumption in China, but the results are inconsistent.  For example, Villegas et al. (2007) carried out a prospective cohort study and found a relative diabetes risk of 1.78 among women who consumed 750 g d^–1 of cooked rice (~250 g d^–1 of uncooked rice) compared with 500 g d^–1.  Similarly, Hu et al. (2012) carried out a meta-analysis which showed that a higher risk of diabetes was associated with higher consumption of white rice in Asian populations, including Chinese people.  However, more recently, Bhavadharini et al. (2020) conducted a Prospective Urban Rural Epidemiology study that found no significant association between the risk of diabetes and white rice consumption in China.

Nevertheless, the risk of diabetes associated with white rice consumption in China may be increasing due to changes in the socioeconomic and physical environments that are associated with rice production.  First, as living standards improve, the demand for and consumption of high eating-quality rice, mainly soft-textured rice with low amylose content, has increased considerably in China (Huang and Hu 2021).  To cater to the changing consumer needs, more new rice varieties with low amylose content have been developed and grown in China.  For example, in the middle reaches of the Yangtze River, the average amylose content declined significantly from 20% in the rice varieties released during 2006–2009 to 16% in those released during 2019–2021 (Huang et al.

2022d).  However, the development of low amylose rice in China has resulted in a substantial acceleration in the rate of digesting starch into glucose in cooked rice and consequently a higher GI (Huang et al. 2022a, b, c, e).  Foods with a higher GI can cause increases in postprandial blood glucose and insulin levels, reductions in insulin sensitivity and pancreatic β-cell function, and hence increase the risk of diabetes (Livesey et al. 2019).

Second, climate warming is being documented around the world.  An increase in temperature during the grain-filling period can result in a reduced grain amylose content in rice varieties with originally low amylose content (Zhong et al. 2005; Yamakawa et al. 2007; Yin et al. 2020; Huang et al. 2022a), because it can reduce both the activity of granule-bound starch synthase and the transfer of glucosyl residues from ADP-glucose to its glucan substrate, which consequently generates fewer amylose molecules (Zeeman et al. 2010; Ahmed et al. 2015).  Moreover, climate warming can increase arsenic availability in soils and the iAs content in rice grains (Neumann et al. 2017; Muehe et al. 2019).  Either the reduced amylose content or the increased iAs content in rice grains may lead to a higher risk of diabetes associated with rice consumption.

While white rice is low in dietary fiber, micronutrients, and polyphenols but high in carbohydrate (starch) and iAs, there is no consistent evidence that a higher risk of diabetes is associated with higher consumption of white rice in China.  However, the development of rice varieties with low amylose content and climate warming may increase the risk of diabetes associated with white rice consumption in China by increasing the GI of cooked rice or/and increasing the iAs content in rice grains.  This highlights the need to fully evaluate the individual and combined effects of the increases in GI and the iAs content on the risk of diabetes associated with white rice consumption.  This evaluation should consider the potential change in per capita consumption of rice.  With a shift to other types of food, such as meat and vegetables, the rice consumption rate per capita is experiencing a downward trend in China (Seck et al. 2012).  In addition, it is also important to develop comprehensive crop, soil, and climate strategies to prevent an increase in the GI of cooked rice and an increase in the iAs content in rice grains, with the goal of avoiding the potentially increased risk of diabetes associated with white rice consumption.

Potato is one of the staple food crops in North China.  However, potato production in this region is threatened by the low amount and high spatial-temporal variation of precipitation.  Increasing yield and water use efficiency (WUE) of potato by various water management practices under water resource limitation is of great importance for ensuring food security in China.  However, the contributions of different water management practices to yield and WUE of potato have been rarely investigated across North China’s potato planting region.  Based on meta-analysis of field experiments from the literature and model simulation, this study quantified the potential yields of potatoes without water and fertilizer limitation, and yield under irrigated and rainfed conditions, and the corresponding WUEs across four potato planting regions including the Da Hinggan Mountains (DH), the Foothills of Yanshan hilly (YH), the North foot of the Yinshan Mountains (YM), and the Loess Plateau (LP) in North China.  Simulated average potential potato tuber dry weight yield by the APSIM-Potato Model was 12.4 t ha^–1 for the YH region, 11.4 t ha^–1 for the YM region, 11.2 t ha^–1 for the DH region, and 10.7 t ha^–1 for the LP region, respectively.  Observed rainfed potato tuber dry weight yield accounted for 61, 30, 28 and 24% of the potential yield in the DH, YH, YM, and LP regions.  The maximum WUE of 2.2 kg m^–3 in the YH region, 2.1 kg m^–3 in the DH region, 1.9 kg m^–3 in the YM region and 1.9 kg m^–3 in the LP region was achieved under the potential yield level.  Ridge-furrow planting could boost yield by 8–49% and WUE by 2–36% while ridge-furrow planting with film mulching could boost yield by 35–89% and WUE by 7–57% across North China.  Our study demonstrates that there is a large potential to increase yield and WUE simultaneously by combining ridge-furrow planting with film mulching and supplemental irrigation in different potato planting regions with limited water resources.

China has 22% of the world’s population but only 7% of the world’s arable land.  Food security has been a chief mission of the Chinese state since the beginning of the dynastic era and remains a primary objective in the early 21st century.  As a result, high yield has been the first priority of farmers, researchers and agricultural agencies in China for a long time.
    Rice is the most important food crop in China, feeding about 65% of the national population.  Rice self-sufficiency has been achieved in China by increasing grain yields by more than 50% since 1980, and this trend is likely to be sustained assuming current yield and consumption trajectories without reduction in production area (Deng et al. 2019).
    As living standards improve, the demand for high quality rice, especially good taste rice, increases in China.  In general, rice with low amylose content and soft texture is preferred by Chinese rice consumers.  This preference has driven considerable changes in rice production of China: (1) in single-season rice cropping regions such as Jiangsu and Heilongjiang provinces, the planting area of soft japonica rice with low amylose content (<15%) has increased substantially while that of non-soft japonica rice with relatively high amylose content has decreased considerably (Zhu et al. 2015); (2) in single- and double-season (early and late seasons) rice mixed cropping regions such as Hunan and Jiangxi provinces, the planting area of early-season indica rice, which is dominated by cultivars with high amylose content (Yin et al. 2020), has decreased sharply (Peng 2016), whereas the planting area of single- and late-season indica rice with moderate to low amylose contents has increased significantly.  Increasing eating quality of rice has also been a focus for Chinese rice researchers and agricultural agencies. New tasty (soft texture) indica and japonica rice cultivars have been increasingly developed and grown in China to cater to consumer preferences (Zeng et al. 2019).
    Improved living standards are also driving up the demand for healthy food in China.  However, rice is generally categorized as a food with high glycemic index (GI).  There is an evidence that rice consumption is significanlty positively associated with the increase in risk of type II diabetes, especially in Asian populations including Chinese (Hu et al. 2012).  Based on the dose-response relation between rice intake and relative risk of type II diabetes plotted by Hu et al. (2012), Song et al. (2017) found that the relative risk of type II diabetes was significantly elevated above 1.00 in China under the current rice intake, i.e., 213 and 256 g d^–1 for women and men, respectively.  In addition, China currently has the highest number of people with diabetes (mainly type II diabetes) in the world, with 114 million or 12% of Chinese adults being diagnosed with diabetes and an additional 493 million with pre-diabetes (Xu et al. 2013).  It is well known that diet management is very important for diabetes care (Sami et al. 2017).  Choosing low-GI foods in place of high-GI foods is a clinically useful way to control glycemic levels in people with diabetes (Brand-Miller et al. 2003).  Therefore, it is meaningful and urgent to produce low-GI rice in China to reduce risk of type II diabetes.  In this regard, it has been found that there is a large variability in GI among rice cultivars.  For example, Fitzgerald et al. (2011) reported that the GI of cooked rice ranged from 48 to 92 in a set of 235 cultivars.
    Our concern is that the current rapid development of tasty rice with soft texture (low amylose content) may increase rather than reduce the risk of type II diabetes in China, because the lower the amylose content of rice, the lower the resistant starch contents (Rahman et al. 2007), the less the resistance to digestion (Hu et al. 2004), and the higher the GI (Fitzgerald et al. 2011).  This concern can be supported by a human diet study of Ohtsubo et al. (2016), who observed that a more drastic increase of postprandial blood glucose occurred in the case of eating low-amylose rice than in the case of eating high-amylose rice and thus concluded that the high-amylose rice is promising for the purpose of diabetes prevention.  Our concern is also supported by a population-based study of 3 918 Chinese adults aged 23–69 years (Cheng et al. 2017), which showed that the consumption of rice with high GI was detrimentally associated with glucose homeostasis and suggested that the preferred choice of rice with lower GI should be advocated.  These also highlight that the cultivar change should be included when modeling the risk of type II diabetes associated with rice intake.
    There is no doubt that low-GI rice with high amylose and resistant starch contents is not preferred by most Chinese consumers in the terms of palatability.  However, in the age of increasing prevalence of non-communicable diseases, most rice consumers are expected to choose health over taste.  Therefore, we appeal that China should begin to consider human health as a target for rice production.  Taken into considerations that (1) GI of rice is not only closely related to its amylose and resistance starch contents but also affected by its other starch traits (e.g., starch gelatinization and retrogradation properties, the particle size of starch granule, the ratio of amylose to amylopectin, the crystallite structure of amylopectin, the starch resistance against enzymatic hydrolysis, and the interactions of starch with other components) and external factors such as cooking conditions (Frei et al. 2003; Rahman et al. 2007; Kaur et al. 2016); and (2) GI of foods and some starch traits such as the resistance starch contents are different depending on measurement method (Brand-Miller and Holt 2004; Walter et al. 2005), we therefore suggest promoting collaborative studies among researchers from various disciplines (crop science, food science and public health) to permit a full understanding of low-GI rice (Fig. 1).  The collaborative studies are not difficult to arrange given that China has established a batch of collaborative innovation centers at national and local levels and has accumulated a wealth of experience.  The studies can start by (1) investigating the digestive properties and glycemic impact of existing rice cultivars with different grain physicochemical characteristics across a wide range of environments, crop management practices and cooking conditions; and (2) considering the minimal extent of desirable palatability for the development of low-GI rice cultivars with high amylose and resistance starch contents in breeding programs.  In addition, it is also important to facilitate the collaboration among academy, government and business to enhance the consumer acceptance of low-GI rice (Jones and Jew 2007).  These works will provide useful information to guide the evaluation, production and promotion of healthy rice in China in the near future.

Blast resistance and grain quality are major problems in hybrid rice production in China.  In this study, two resistance (R) genes, Pi46 and Pita, along with the gene Wx^b, which mainly affects rice endosperm amylose content (AC), were introgressed into an elite indica restoring line, R8166, which has little blast resistance and poor grain quality through marker-assisted selection (MAS).  Eight improved lines were found to have recurrent genome recovery ratios ranging from 88.68 to 96.23%.  Two improved lines, R163 and R167, were selected for subsequent studies.  R167, which has the highest recovery ratio (96.23%), showed no significant differences in multiple agronomic traits.  In contrast, R163 with the lowest recovery ratio (88.68%) exhibited significant differences in heading date and yield per plant compared with the recurrent parent.  At two developmental stages, R163 and R167 had greatly enhanced resistance to blast over the recurrent parent.  Similar trends were also observed for agronomic traits and blast resistance in R163- and R167-derived hybrids when compared with the counterparts from R8166.  In addition, R163, R167, and their derived hybrids significantly improved the grain quality traits, including amylose content (AC), gel consistency (GC), chalky grain rate (CGR), and degree of endosperm chalkiness (DEC).  It confirmed the success of efficiently developing elite restoring lines using MAS in this study.

China’s Super Hybrid Rice Breeding Program has made significant progress over the past two decades.  In this paper, we reviewed our studies on the yield potential and stability in super hybrid rice and discussed the strategies for super hybrid rice production.  The results of our studies show that rice yield potential has been increased by 12% in super hybrid cultivars as compared with ordinary hybrid and inbred cultivars.  The higher grain yields in super hybrid rice cultivars are attributed to larger panicle size coupled with higher biomass production or higher harvest index.  However, grain yields in super hybrid rice cultivars vary widely among locations depending on soil and climatic factors.  Therefore, it is important to tailor target yield to local conditions in super hybrid rice production.  The target yield for super hybrid rice production can be determined by the average yield method or the regression model method.  Improving soil quality is critical to achieving the target yield in super hybrid rice production.  Favorable crop rotations such as rice-oilseed rape and novel soil management practices, such as biochar addition, are effective approaches to improve soil quality.  It is needed to develop simplified cultivation technologies for super hybrid rice to meet the changes in socioeconomic environments during the period of transition.  There are such technologies as no-tillage direct seeding and mechanized transplanting at high hill density with single seedling per hill.

   Recently, a new bacterial top rot disease of maize has frequently appeared in many areas of Yunnan Province, China. The pathogen of the disease was identified as Klebsiella pneumoniae (KpC4), which is well known to cause pulmonary and urinary diseases in humans and animals and occasionally exists as a harmless endophyte in plants. To evaluate the virulence of the maize pathogen to maize and mice, we inoculated maize and mice with routine inoculation and intraperitoneal injection respectively according to Koch’s postulates. The results showed that KpC4 and the clinical strain K. pneumoniae 138 (Kp138) were all highly pathogenic to maize and mice and the strain re-isolated from diseased mice also caused typical top rot symptoms on maize by artificial inoculation. It is highlighting that a seemingly dedicated human/animal pathogen could cause plant disease. This is the first report of K. pneumoniae, an opportunistic pathogen of human/animal, could infect maize and mice. The findings serve as an alert to plant, medical and veterinarian scientists regarding a potentially dangerous bacterial pathogen infecting both plants and animals/humans. The maize plants in the field could serve as a reservoir for K. pneumoniae which might infect animals and probably humans when conditions are favorable. The new findings not only are significant in the developing control strategy for the new disease in Yunnan, but also serve as a starting point for further studies on the mechanism of pathogenesis and epidemiology of K. pneumoniae.

In order to understand the yield performance and nitrogen (N) response of hybrid rice under different ecological conditions in southern China, field experiments were conducted in Huaiji County of Guangdong Province, Binyang of Guangxi Zhuang Autonomous Region and Changsha City of Hunan Province, southern China in 2011 and 2012. Two hybrid (Liangyoupeijiu and Y-liangyou 1) and two inbred rice cultivars (Yuxiangyouzhan and Huanghuazhan) were grown under three N treatments (N1, 225 kg ha–1; N2, 112.5–176 kg ha–1; N3, 0 kg ha–1) in each location. Results showed that grain yield was higher in Changsha than in Huaiji and Binyang for both hybrid and inbred cultivars. The higher grain yield in Changsha was attributed to larger panicle size (spikelets per panicle) and higher biomass production. Consistently higher grain yield in hybrid than in inbred cultivars was observed in Changsha but not in Huaiji and Binyang. Higher grain weight and higher biomass production were responsible for the higher grain yield in hybrid than in inbred cultivars in Changsha. The better crop performance of rice (especially hybrid cultivars) in Changsha was associated with its temperature conditions and indigenous soil N. N2 had higher internal N use efficiency, recovery efficiency of applied N, agronomic N use efficiency, and partial factor productivity of applied N than N1 for both hybrid and inbred cultivars, while the difference in grain yield between N1 and N2 was relatively small. Our study suggests that whether hybrid rice can outyield inbred rice to some extent depends on the ecological conditions, and N use efficiency can be increased by using improved nitrogen management such as site-specific N management in both hybrid and inbred rice production.

The pink bollworm, Pectinophora gossypiella (Lepidoptera: Gelechiidae) is one of the most serious lepidopteran pests of cotton in the world. This pest invaded China at the onset of the 20th century, possibly through repeated introductions from several different locations worldwide. In this paper, we describe different behavioral parameters of this Hubei P. gossypiella strain under laboratory and field conditions. Using an infra-red video recorder, we observed (nocturnal) emergence, flight and mating activities, and oviposition patterns. Moth emergence started from 13:00 and continued up till 23:00. Under laboratory and field conditions, 2-7-d-old moths initiated flight around sunset, peaked 50 min later and gradually declined until 04:00. Although mating started immediately after darkness (i.e., 20:00), mating behavior was most intense from 23:00 to 03:40. Oviposition also showed distinct time-related patterns, with approx. 70% eggs laid between 20:00 and 22:00. In the studies of the relationship between flight and oviposition, the duration of flight had an effect on oviposition. The 1-d-old moths flown for 6 and 12 h began oviposition earlier than the unflown ones, and the 6-h flight had no effect on the egg production. However, the longevity of the flown moths was shortened after flight. In addition, the peaks of oviposition for the flown moths were advanced 2-3 d. The age when the moths flied affected the oviposition of adult moths. The earlier the moths started to fly after emergence, the greater the fecundity they had. The average egg production of moths flown for 24 h was less than that of non-flown moths which were of the same age. Both flight and delay in mating could advance the oviposition peak. Our study provides detailed insights in nocturnal activities and the reproductive biology of local P. gossypiella populations, which could be employed to fine-tune current pest management programs in China.

To compare the grain yield and growth behaviors of hybrid rice, field experiments were conducted in a subtropical environment in Changsha, Hunan Province, China, and in two tropical environments in Gazipur and Habiganj in Bangladesh during 2009 to 2011. Three hybrid rice cultivars were grown under three nitrogen (N) management treatments in each experiment. The results showed that grain yield was significantly affected by locations, N treatments and their interaction but not by cultivars. Changsha produced 8-58% higher grain yields than Bangladesh locations. Sink size (spikelet number per unit land area) was responsible for these yield differences. Larger panicle size (spikelet number per panicle) contributed to greater sink size in Changsha. Aboveground total biomass was greater in Changsha than in Bangladesh locations, whereas harvest index was higher in Bangladesh locations than in Changsha. Crop growth rate (CGR) was greater at Changsha than Bangladesh locations during vegetative phase, while the difference was relatively small and not consistent during the later growth phases. Higher leaf area index and leaf area duration were partly responsible for the greater CGR in Changsha. Real-time N management (RTNM) produced lower grain yields than fixed-time N management in more than half of the experiments. Our study suggested that further improvement in rice yield in the tropical environments similar to those of Bangladesh will depend mainly on the ability to increase panicle size as well as CGR during vegetative phase, and the chlorophyll meter threshold value used in RTNM needs to be modified according to environmental conditions and cultivar characteristics to achieve a desirable grain yield.

Chinese super hybrid rice breeding project has developed many new varieties with great yield potential. It is controversial which yield component should be emphasized in super hybrid rice production. The present study was conducted to compare super hybrid rice with common hybrid and super inbred rice and analyze contributions of yield components to grain yield of super hybrid rice under experimental conditions, and evaluate relationships between grain yield and yield components of super hybrid rice in farmer’s paddy fields. Field experiments were done in Changsha, Guidong, and Nanxian, Hunan Province, China, from 2007 to 2009. Eight super hybrid varieties, one common hybrid variety, and one super inbred variety were grown in each location and year. Rice production investigation was undertaken in high-yielding (Guidong), moderate-yielding (Nanxian), and low-yielding (Ningxiang) regions of Hunan Province, China, in 2009. Grain yield and yield components were measured in both the field experiments and rice production investigation. Super hybrid rice varieties outyielded common hybrid and super inbred varieties across three locations and years. Yield potential has been increased by 11.4% in super hybrid rice varieties compared with common and super inbred varieties. The higher yield of super hybrid varieties was attributed to improvement in panicle size. Panicles per m2 had the highest positive contribution to grain yield with the exception under yield level of 10.0 to 12.0 t ha-1, and was positively related to grain yield in farmer’s field at all of the high-, moderate-, and low-yielding regions. Our study suggests that panicle per m2 ought to be emphasized in super hybrid rice production.