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

DEVELCHENT OF HYBRID ~ IN THAILAN>
C. Chutkaew J1, N. Senanarong z.! R. Thiraporn ~ U. Pupipat ~ C. Kitbamroong ~
S. Jampatong..§.{ C. Aekatasanawan 11, P. Grudloyma1!.( S. Noradechanon ~
S. Lim-aroon ~ Y. Juthathong ~ and S. 80nwai ~
Abstract
Since 1950, corn has been one of the most important econanic crops of Thailand. In 1984,
exports of corn grain reached a maximum value of 10,149 m Baht and exports of canned baby corn
has also come to play an important role, earning 961 m Baht in 1991 (1 US$=25.2 Baht). However,
the planted area has declined, and the fast growth of the feed industry demands greater supplies
of corn grain.
High yielding hybrid corn and expansion of area by planting corn in paddy fields during the
dry season where irrigation is available would make it possible to meet the national demand of
the grain.
The first high yielding open pollinated variety (OPV), Phra-Phutthabat (PB), was released
around 1961. It was replaced by two OPVs: Thai DMR 6 in 1972 and SUWan 1 in 1976. The other
open pollinated varieties released were SUWan 2 (early maturity) in 1979, Rangsit 1 baby corn in
1981, SUwan 3 in 1987, Nakhorn sawan 1 in 1989, and most recently, SUWan 5 in 1993.
All of these OPVs are good sources of germplasm for inbred line extraction and are used in
both public and private hybrid corn breeding programs. So far, 44 Kasetsart inbred lines (Ki 1
to 44) have been released by the Corn Breeding Project of Kasetsart University (KU). The
released hybrids are Kasetsart Single Cross 2301 (KSX 2301) or SUWan 2301, in 1982; Kasetsart
Three-way Cross 2602 (KTX 2602) or SUwan 2602 in 1986; KTX 3101 or SUWan 3101, in 1991; and the
Kasetsart Baby Corn Three-way Cross 3501 or KBTX 3501, in 1993. The hybrids expected to be
released shortly are KOSX 3503, KSX 3504, NSX 9002, and NSX 9008.
These hybrids embody genetic improvements which make possible higher yields and better
agronomic characteristics, such as greater resistance to root and stalk lodging, diseases,
insects, barrenness and greater tolerance of drought and high plant densities.
The first recorded sale of hybrid corn seed was 40t in 1981. In 1993, an estimated 10,000 t
of hybrid corn seed were sold in Thailand. The successful development of hybrid corn in Thailand
has depended in part upon cooperation through the years of different agencies, including USAID,
Rockefeller Foundation, CIMMYT and FAD, as well as of visiting scientists.
Introduction.
Corn Zea mays has become one of Thailand's leading economic crops over the past four
decades, important both as an export product and as an animal feedstuff. Exports of corn grain
have increased drastically from only 12,630 t valued at 10,479,000 Baht in 1950 to 3,982,440,000
t, worth 10,149,816,000 Baht in 1984. The 42 year (1950-1991) maximum (Table 1). Also important
is baby corn. Exports of canned baby corn have risen from 67 t, worth 961,490,000 Baht in
J1 Dept. of Agronomy, and Lop Buri Exp. Sta., KU .
.1J Field Crops Res. Inst., DOA.
1Y Dept. of Agronomy 'and Inseechandrastitya Inst. of Crop Res. & Dev., KU.
~ Dept. of PLant Pathology, KU.
21 Chainat Field Crops Res. Center, DOA.
~ ,11 ,W ,1JJ Natl. Corn & Sorghum Res. center (Suwan), KU.
!JJ,~
J.1l
Nakhonsawan Field Crops Res. Center, DOA.
Un iseeds Co.
130