The role of exotic wheat germplasms in wheat breeding and their impact on wheat yield and production in China

Wheat is the second most important food crop in China and its yield has increased significantly since the early 1980s. While the rise in yield is obviously owed to the adoption of modern varieties and the rising use of inputs, little research has examined the yield gains as a result of the improvement of germplasms through international exchanges in the domestic breeding program. This study aims to understand the uses of exotic germplasms in wheat varieties adopted by farmers and their contributions to wheat yield and production in China. Based on unique data on major wheat varieties adopted by farmers and their pedigree in 17 major wheat production provinces in the period between 1982 and 2014, descriptive analyses show that the varieties with germplasms from CIMMYT (International Maize and Wheat Improvement Center) and other countries (or Others) accounted for 19% and 81%, respectively, in the major varieties adopted by farmers. While the direct adoption of exotic varieties in production has been falling, the use of exotic germplasms in wheat breeding has increased over time. Moreover, the varieties with both, Chinese and exotic germplasms, normally had higher average yields than the varieties with Chinese germplasms alone in most periods studied. The econometric analysis further shows that when compared with the varieties with pure Chinese germplasms, those with exotic germplasms contributed higher yields. Without the germplasms from CIMMYT and Others, the average annual yield would be lowered by 63 kg/ha and 323 kg/ha, respectively, during 1982–2014. The estimated increase in wheat production as a result of using exotic germplasms reached 10.4 million tons annually and has increased over time in the past three decades. The paper concludes with several policy implications for China's plant breeding strategy and for international donors funding the germplasm program.