Cabbage (Brassica oleraceae L.var.capitata L.f.alba DC.)

The planted area under cabbage in 1994 was 45 408 rai; it has been increased by 39.2 percent to reach 63 220 rai in 1998 with a production of 188 914 tons. Leading production regions were the north (164 232 tons) and the northeast (13 858 tons) in 1998. Provinces of high production are Nan, Payao, Maehongson, Tak and Phetchabun.
All cabbage seeds are imported from temperate countries. Most of them are hybrid seeds. Japanese seed companies are the leaders in the cabbage seed market. Recommended cultivars/hybrids are:
The 60-DAY NO.1 (Chia Tai):
a uniform hybrid, highly heat-tolerant, flat-globe head shaped with an average head weight of 1.5–2.0 kg. It is a sweet-flavored hybrid with crispy leaves. The crop matures in 55–60 days after transplanting.
KY-CROSS (Japanese hybrid):
it is widely cultivated as it is heat-tolerant. The head is a flat-globe with blue-green leaves and with an average weight of 1.6 kg. It is suitable for growing from the latter part of the rainy-season to the beginning of the cool season.
COPENHAGEN MARKET (Chia Tai, OP):
the cultivar is best suited to the end of the monsoon or the beginning of the cool season. The round heads are compact, with thick leaves and are of bright greengrey colour. Maturity is 70–80 days after transplanting.
Cabbage will remain an important crop and production is expected to increase in the future. Heat-tolerant cultivars enable cultivation at lower elevations, but market gardening will continue to prevail in the highlands because of higher yield potential, better head quality and fewer disease and pest problems. Introduction of effective methods of integrated pest management (with emphasis on diamond back moth control) are much needed.

Pak choi (Brassica chinensis L. var.parachinensis Bailey)

During the last five-year period the production area of pak choi has been steadily increasing. The planted area was 67 403 rai in 1994 with a 27.8 percent increase in 1998. The planted area in 1998 was 86 145 rai with a production of 146 668 tons. It is one of the main leafy vegetables of the Brassica group of crops in Thailand. It is currently being promoted to be grown under the insecticide-free program for healthy food due to its popularity. Pak choi is mainly cultivated in the Northeast (21 687 rai). North (20 799 rai) and West (14 451 rai). The provinces that have large-scale planted areas are Nakhonsawan, Lamphun, Nakhonratchasima, Nonthaburi and Pathumthani.
Pak choi is grown mainly from open-pollinated cultivars. These are:
NAN 60 (DOA):
large plants with long petiole.
BANGLUANG 006 (DOA):
the plant is large, stout, with a long petiole and less branching. The leaves are thick, green and oblong. It is suitable for any tropical climate and is both heat and disease tolerant.
KRUNG THEP 170 (Chia tai):
the plant is vigorous, large, disease tolerant, bolt-resistant and has less branching. The leaves are large, green and slightly wavy.
The potential to genetically improve pak choi using the variation in presently available cultivars seems to be limited. Germplasm collections are maintained by the universities and the Department of Agriculture. Breeding efforts are normally aimed at developing cultivars with thick leaves and petioles. Research work on integrated pest management is required. More research on organic farming and chemical-free production with the advantage of its fast growth, would promote pak choi production and consumption.