《PNAS Nexus》| CCAP has achieved new findings on the impact of high-yield wheat and maize crop varieties on infant mortality rates in China.

Release date：2025/02/24　　Source： CCAP

In the 1970s and 1980s, China began large-scale promotion of high-yield wheat and maize varieties, significantly enhancing grain production and becoming a pivotal component of China's "Green Revolution." However, previous studies on the micro-level impacts of these improved crop varieties on human health and welfare, particularly on infant mortality, remain limited. At the same time, infant mortality is a critical indicator for assessing a nation's human development, poverty alleviation efforts, and balanced regional economic growth, drawing considerable attention from global public health experts. During the mid-20th century, China experienced a remarkable decline in infant mortality rates, a trend closely aligned with advances in agricultural technology. Nevertheless, the causal relationship between these two phenomena has yet to be adequately verified.

The research team utilized data from the 1985 and 1987 China In-depth Fertility Surveys, combined with data on the adoption of high-yield wheat and maize varieties, to construct a long-term dataset spanning 1954 to 1987, covering major wheat and maize cultivation regions in northern China, particularly the Huang-Huai-Hai Plain. Employing a two-way fixed-effects model, the study analyzed the relationship between the adoption of high-yield varieties and infant mortality rates, examining potential mechanisms such as increased grain production, improved infant nutrition, and changes in maternal characteristics.

The findings revealed a significant association between the spread of high-yield wheat and maize varieties and reductions in infant mortality. Specifically, from 1954 to 1987, the average weighted potential yield increase of wheat and maize led to an approximate 0.14 percentage point decline in infant mortality rates. This relationship remained robust even after excluding famine years, suggesting a lasting positive impact from the adoption of improved crop varieties. Notably, the adoption of high-yield wheat varieties had a more pronounced effect on lowering infant mortality compared to maize, likely due to wheat's critical nutritional role for pregnant women and infants.

Figure 1. The Impact of High-Yield Crop Adoption on Infant Mortality: Baseline Results and Robustness Checks

The study further explored the potential mechanisms linking the adoption of improved crop varieties to reductions in infant mortality. Results indicate that the spread of high-yield varieties significantly increased grain production, improved nutritional intake for infants, and notably increased the prevalence and duration of breastfeeding, which emerged as critical mechanisms reducing infant mortality.

Moreover, the analysis revealed heterogeneity in the relationship between the adoption of high-yield varieties and infant mortality. The beneficial impact was more pronounced among male infants, potentially due to China's traditional preference for males and the inherently greater vulnerability of male infants. Additionally, the study found no significant difference in the impact of improved crop varieties on infant mortality rates before and after the implementation of family planning policies, suggesting that the positive effects remained consistently stable over the long term.

Figure 2. Mechanism Analysis: The Impact of High-Yield Crops on Grain Production and Breastfeeding Practices

The findings of this study offer important policy implications for agricultural technology dissemination globally. Given that many developing countries continue to face food and nutritional insecurity, enhancing the promotion of high-yield crop varieties can not only boost agricultural productivity but also significantly reduce infant mortality through improvements in nutrition and health. This research provides robust evidence for the connection between advancements in agricultural technologies and human health outcomes, offering valuable insights for global agricultural policy formulation. The study underscores that continuous innovation and dissemination of agricultural technologies are critical, not only for addressing food security challenges but also for improving human health and welfare.

The results discussed above were published under the title “The influence of improved wheat and maize varieties on infant mortality in China” in the journal PNAS Nexus on February 20, 2025. Professor Wang Xiaobing and doctoral graduate Liu Xinyu from the China Center for Agricultural Policy at Peking University are co-first authors, while Professor Huang Jikun from the China Center for Agricultural Policy at Peking University and Professor Songqing Jin from Michigan State University are corresponding authors. Additional collaborators include Professor Scott Rozelle's team from Stanford University, Professor Min Shi from Huazhong Agricultural University, and Dr. B.M. Prasanna from CIMMYT. This research was supported by major projects funded by the National Social Science Fund of China and the National Natural Science Foundation of China.

Author Biographies

Xiaobing Wang (First Author)
Professor Xiaobing Wang currently serves as a professor and doctoral supervisor at the School of Advanced Agricultural Sciences at Peking University and is also a researcher at the China Center for Agricultural Policy, Peking University. She is a committee member of the 16th Central Committee on Agriculture and Rural Development of the China Zhigong Party. Her primary research areas include agricultural technology development and policies, food security, and poverty alleviation. Her research has been published in leading international and domestic academic journals, including the American Journal of Agricultural Economics, Journal of Economic Behavior & Organization, World Development, Economic Development and Cultural Change, Global Food Security, and Chinese Rural Economy. From 2020 to 2024, she was consistently listed as a highly cited researcher in agricultural and forestry economic management by Elsevier. Her research achievements have also been featured by mainstream media, including the Publicity Department of the Communist Party of China's platform "Xuexi Qiangguo," Guangming Daily, and Science and Technology Daily.

Jikun Huang (Corresponding Author)
Professor Jikun Huang is Dean of the School of Advanced Agricultural Sciences at Peking University, Boya Chair Professor, Distinguished Professor of the Changjiang Scholars Program, Director of the Institute of New Rural Development, and Honorary Director of the China Center for Agricultural Policy at Peking University. He is a member of The World Academy of Sciences (TWAS), an Honorary Life Member of the International Association of Agricultural Economists, Fellow of the Agricultural & Applied Economics Association (AAEA), and former President of the Asian Society of Agricultural Economists. He also serves as editor or editorial board member for over 30 international and domestic journals. Professor Huang is a specially appointed expert in the advisory talent pool of the Chinese People's Political Consultative Conference (CPPCC), and a member of several expert advisory committees, including the Ministry of Agriculture and Rural Affairs' Rural Revitalization Advisory Committee, the Science and Technology Innovation Strategy Advisory Committee, and expert committees for China's 14th and 15th Five-Year National Development Plans. He received his bachelor's degree from Nanjing Agricultural University in 1984 and his PhD from the University of the Philippines in 1990. He primarily focuses on agricultural and rural development research and has been recognized with the National Science Fund for Distinguished Young Scholars. Professor Huang has published over 640 papers in leading journals such as Science, Nature, and economics and management fields. He has been honored with prestigious awards, including the China Young Scientist Award, the Fudan Management Outstanding Contribution Award, multiple provincial and ministerial-level science and technology progress awards, and first prize for research achievements in economics from the Ministry of Education.

Original link：https://doi.org/10.1093/pnasnexus/pgaf048