GENETIC IMPROVEMENT OF WHEAT YIELD POTENTIAL AND ADAPTATION IN CHINA - Soybean and Wheat Crops: Growth, Fertilization, and Yield - page 184

Chapter 10
G ENETIC I MPROVEMENT OF W HEAT Y IELD
P OTENTIAL AND A DAPTATION IN C HINA
Zhonghu He 1,2,* and Xiaoke Zhang 3
1 Institute of Crop Science, National Wheat Improvement Center/The National Key
Facility for Crop Gene Resources and Genetic Improvement,
Chinese Academy of Agricultural Sciences (CAAS),
12 Zhongguancun South Street, Beijing 100081, China
2 CIMMYT China Office, C/O CAAS, Zhongguancun South Street,
Beijing 100081, China
3 College of Agronomy,
Northwest Sci-Tech University of Agriculture and Forestry,
Yangling, Shaanxi 712100, China
A BSTRACT
Genetic improvement of yield potential has always been an important objective in
China. Averaged annual genetic gain in grain yield ranged from 13.96 kg/ha/year to
72.11 kg/ha/year or from 0.31% to 1.23% annually in different wheat regions. The
genetic improvement in grain yield was primarily attributed to increased grain weight per
spike, reduced plant height, and increased harvest index. Three dwarfing genes and
1B/1R translocation have been successfully used in wheat production. Rht-D1b (45.5%)
and Rht 8 (46.8%) were more frequent, followed by Rht-B1b (24.5%). The frequencies of
Rht-B1b and Rht-D1b increased, from 8.6% to 32.2% and 36.2% to 53.4%, respectively,
whereas the frequency of Rht8 has remained constant over time, when compared with
cultivars released before and after 1990. From the late 1970s to the early 1990s, wheat
breeding in autumn-sown wheat regions focused on the utilization of the 1B/1R
translocation. The dominant Vrn-D1 allele showed the highest frequency in Chinese
wheat cultivars (37.8%), followed by the dominant Vrn-A1 , Vrn-B1 , and Vrn-B3 alleles.
All cultivars released in the Northern Winter Wheat Zone were winter type. Winter