Proceedings of the Fifth Asian Regional Maize Workshop - Search ...

aRBff STAnJS OF MAIZE HYIIUD ER:EDIftG AN} IlS STRATEGIES IN am~
Peng Zebin-Uand Chen Zehui.:£f
Abstract
China is now the second largest maize producing country in the world behind the USA. In
1991, total maize area reached 21.6 m ha and the average yield was 4.6 t/ha. The area pl~ted
with hybrids is over ~ of the total cultivated area, and in 1992 a total of 27 hybrids were
grown in areas over 100 thousand ha. There were four main germplasm sources of hybrid maize, but
nearly 34~ of the hybrid production reported contained Lancaster germplasm. Ludahonggu germplasm,
with 19.07~, was the second most important, followed by Reid and Tangsipingtou with 14.4~
and 13.8% area, respectively. The narrow genetic background is the main problem maize breeders
are facing. In 1992, 52.21~ of all new inbred lines were selected from single crosses, 10.44~
from synthetics, and 10.44~ from three-way crosses. The plant ideotype is an important character
considered in hybrid development in China. Many hybrids with good plant architecture have been
developed in recent years.
The area planted to maize in the three southwest provinces (Yunnan, Gui zhou , and Guangxi)
is large, but with low productivity due to a low percentage of area planted with hybrids and poor
maize growing conditions. The germplasm used in the region includes temperate, subtropical,
tropical highland and tropical lowland materials. Single crosses, three-way crosses, double
crosses, top crosses, and OPV's are popular in this region.
Maize hybrid breeding in China
Maize hybrid breeding in China was initiated in the 1950's. Similar to some developed
countries, maize hybrid breeding in China began with varietal cross hybrids, followed by top
cross hybrids, double crosses, three-way crosses, and single crosses. It was through the
utilization of maize hybrid breeding technology that varietal cross hybrids such as Fangza 2,
Chunza 2, and the topcross hybrids Nongda 1, and Wuding 1 were successfully released. A group of
double crosses such as Nongda 4, Nongda 7, and Chunza 12 were widely used since 1956, contributing
a great deal to increase maize production of China. In the late 60's single cross hybrids
were developed and put into production. The research efforts of more than twenty years led to
the rapid increase of maize production in China. China now is the second largest maize producing
country following the USA. In 1991 the total maize area reached 21.574 m ha with an average
yield of 4.575 t/ha (Table 1), according to the statistics of the National Seed Administration.
In 1992, there were 112 hybrids grown in areas above 10,000 ha. Today the maize area planted
with hybrids is over 8~ of the total maize area cultivated in China (Fig. 1).
The varieties have been renewed four times since the adoption of single crosses in the
late 1960's. The typical varieties used at various times were:
Generation one: Xindan 1, Baidan 4
Generation two: Qundan 105
Generation three: Danyu 6, Zhendan 2, Jian 101
Generation four: Zhongdan 2, Yandan 14, Danyu 13
-!J Maize breeder, Crop Breeding Inst., Chinese Acad. of Agric. Sci., 30 Bai Shi Qiao Road, west
Suburbs, .Bei j ing, P.R. China.
-fJ Vice director, Upland Crops Inst., Guizhou Acad. of Agric. Sci., Jinzhuzhen, Guiyang 550006,
Guizhou, P.R. China.
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