The grain sorghum planting area in Thailand has dramatically decreased due to the grain price being so depressed. As a response to this, Mr.Seriwat and his co-workers of the Department of Agriculture have now made some adjustments to their sorghum breeding program. Details of this is presented in this most recent bulletin.

The productivity of some hybrid maize varieties under five different soil series at Nakhon Sawan Field Crops Research Centre are also described. The principle researcher, Mr. Satit, found that some maize varieties yielded better than others on particular soil series. In addition, Mr.Chollawuth and Dr. Teerasak found that applications of chicken manure at the rate of 1 ton per rai (1 rai = 0.16 ha.) per year for 13 years, not only improved soil fertility, but also improved maize yield. Moreover, it was shown that by including legumes in the cropping rotation, improvement to soil fertility were achieved and increases were made to the yield of maize. The optimum cropping system was found to be Maize-Mungbean with a recommended fertilizer application to maize at the rate of 10-5-5 kg/rai. This resulted in a higher marginal rate of return when compared to the chicken manure treatment.

In 2004, 1.13 million ha. were planted to maize for Thailand. About 0.63 million ha. (56.13%) were in the Northern part, 0.27 (23.97%) were in the North-eastern part and 0.22 (19.90%) were in the Central plain of Thailand. The average yield for each part were 623, 552, 604, and 602 kg/rai in the North, North-eastern, Central plain, and overall the country, respectively. The difference in yield between each part of the country was dependented on the different soil series and others production problems which has been reported upon by Dr. Teerasak, in co-operation with AMTC, a survey is presented for each location over maize growing area.

Maize yields in Thailand are low when compared to some others countries. Improving base populations for further breeding programs are necessary. Advantage and dis-advantages of prolific and non-prolific genotype populations are still controversially. These issue have been the focus of study by Dr. Sansern in his Ph.D. dissertation. At the same time, Dr. Chaba used the QTL technique to conferred the resistant gene in Mo47 inbred lines for ECB resistance in maize.

In addition to the work on maize and sorghum, other important work is being conducted on tobacco. Although cigarette consumption is on the decrease. Thailand continues to imported about 6.95 m$(net) of tobacco for manufacture of cigarettes. The article presented here describes the work of Mr. Jirasak and his colleague detailing methods used to improve the yield and quality of the tobacco through their breeding program, enabling reductions to be made to decrease import value. Please read on for further details of this and other issues.

The editor is appreciated Dr. Ian Grange for his valuable advice and edited some papers here.

Teerasak Manupeerapan