Grain sorghum research and development in 1995-1996 continues to have emphasis on the selection of pure lines, grain yield evaluation of pure lines and hybrids and evaluation of introduced varieties from A & M University, Texas and Georgia populations.

Sorghum populations have continued to be introduced from Georgia University since 1991 and 10 potential lines have been extracted. These lines were tested in regional yield trials together with the check varieties, U-Thong 1 and Suphan Buri 60, at 4 locations across the sorghum belt area. The objective of the trial was to study their yield performances at each of the locations. A randomized complete block design was used with 4 replicates. The results showed that, in general, the experimental mean yield at Nakhon Sawan FCRC was the highest followed by Suphan Buri FCRC, Ban Mai Sam Rong FCRES and Praphuthabat FCRES giving 4,375, 3,600, 2,843 and 1,468 kg/ha respectively. This indicated that environmental condition at Nakorn Sawan FCRC, for this year, was suitable for the growth of sorghum and lead to a high yield. Inappropriate land preparation at Praphuthabat FCES may have caused the lowest experimental mean yield. Yield performance of each tested line vary depended on the location. For example, at Suphan Buri FCRC, I 131-6 gave 50 % higher grain yield than U-Thong 1 and I 701-3 gave 44 % and 47 % higher grain yields than U-Thong 1 at Ban Mai Sam Rong FCES and Suphan Buri FCRC respectively, and I 461-3 also gave 25 % higher grain yield than U-Thong 1 at Ban Mai Sam Rong FCES. These promising lines have longer maturity than U-Thong 1and 8 % higher grain yields than U-Thong 1 at Suphan Buri FCRC, Nakorn Sawan FCRC and Praphuthabat FCRES, respectively. These lines have a creamy grain color. Sorghum line UT 428-3 obtained from the national breeding program which have red grain color also has a grain yield of about 17 % higher than that of Suphan Buri 60 as was shown from the experiment conducted at Praphuthabat FCREC. This result was similar to last years results.

Six introduced sorghum lines were grown together with 3 promising lines derived from a national breeding program including 3 check cultivars in RCB with 4 replicates. The experiment was conducted at 5 locations which aimed to study the performances of yield under the various growing conditions of the sorghum belt area. This was the second year of the experiment. The results indicated that, in general, the experimental yield was highest at Nakorn Sawan FCRC followed by Suphan Buri FCRC, Ban Mai Sam Rong FCRES, Praphuthabat FCRES and Phetchaboon FCRES with average yields of 5,637, 3,331, 3,056, 2,137 and 1,993 kg/ha, respectively. The results indicated that the growing conditions at Nakorn Sawan FCRC, in 1996, more favorable for growth and gave higher yields than the others. Praphuthabat and Phetchaboon FCRES showed unsuitable growing condition. In particular, at Phetchaboon FCRES, a high C.V. (%) was obtained (31.5 %) though the results were not included in the combined analysis. The results from the remaining 4 locations indicated that the yield performances of each line varied depending on location. For instances, TA 39 gave 55 %, 17 % and 25 % higher than U-Thong 1 at Ban Mai Sam Rong FCRES, Suphan Buri FCRC and Nakorn Sawan FCRC, respectively. Sorghum line, TA 46 gave 25 %, 12 % ent and the thresher speed to produce good quality sorghum seed. The experiment was conducted in 3 x 4 factorial in RCB with 3 replicates in 1995. Seed moisture content was the first factor with 4 levels these being 14 % (at harvest), 13 % (1 day sun dried), 12 % (2 days sun dried) and 10 % (3 days sun dried). Three levels of thresher speed (attached to the tractor) 550, 700 and 800 rpm was the second factor. The results indicated that the actual seed moisture content did not meet the requirement of the treatment. The highest seed moisture content was 12.7 % whereas the lowest was 10.8 %. The moisture contents seem to be low to cause the differences in fragile seed weight however, they were about 31.9 gram/kg of seed. The thresher speed was found to be significant difference. More fragile seed weight was found at 800 round/min (35.9 gram/kg of seed). At 700 round/min showed the lowest of fragile seed weight (29.2 gram/kg of seed).

Sorghum lines from Texas have been introduced and tested since 1991 and 4 promising lines have been selected. These lines are TA 46, TA 48, TA 18 and TA 39. The experiment was conducted in 5 locations in order to study their yield performances in the farmer fields across the sorghum belt areas. RCB with 4 replicates were used in this study. High variations were obtained from the trial at Suphan Buri, and hence, the data were not included in the analysis. The results from the other 4 locations indicated that Nakhorn Sawan followed by Ban Mai Sam Rong, Phraphuthabat and Pethchaboon have the most suitable growing conditions giving yields of 4,681, 3,381, 2,937 and 2,643 kg/ha, respectively. The performance of each of the lines also differed between locations. For example, TA 18, red grain color, gave higher grain yield than Suphan Buri 60 at Ban Mai Sam Rong and Phraputhabat at 4 % and 10 % respectively. TA 39, creamy grain color, gave higher grain yields than U-Thong 1 at Ban Mai Sam Rong and Phetchaboon at 14 % and 47 % respectively. TA 39 has long maturity and plant height is slightly tall compared with U-Thong 1 whereas TA 18 is medium tall and the flowering time is close to the check cultivars.

In 1995 the selected red grain sorghum lines which derived from the F 6 generation were tested together with the check varieties, Suphanburi 60, Suphanburi 1 and Late Hegari. The objective of the trial was to study their yield performance and agronomic traits. Three replications of double row plots 6.0 m long and 0.6 m wide were planted at Suphanburi Field Crops Research Center. The results showed that all of these lines had an average grain yield more than the short stem check variety, Suphanburi 60. There were some lines that had grain yields more than the dual purpose check variety, Suphanburi 1 such as UT94LR1256B and UT94LR1277B. These two lines had stem heights that were the same as Suphanburi 1.

The objective of this study was to evaluate yield performance at 4 different locations. The trial was conducted in a randomized complete block design with four replications. In 1995, twelve red grain sorghum lines which had average grain yields more than Suphanburi 60 in the previous year were planted, together with the check varieties, Suphanburi 60, Suphanburi 1 and Late Hegari. The results showed that the yield performance of each tested line varied depending on the location. For example, UT 429-1 and UT 249-3 gave the highest grain yield and significantly differed from Suphanburi 60 at Nakhonsawan Field Crops Research Center, whereas UT 395-4 gave the highest grain yield and significantly differed from Suphanburi 60 and Late Hegari at Suphanburi Field Crops Research Center. The average grain yield across the 4 locations showed that all of these lines had average grain yields of more than the Late Hegari and Suphanburi 60. The lines UT 249-3 had the highest grain yield at about 4 t/ha.
In 1996, thirteen selected red grain sorghum lines were planted at 5 locations, but some of these lines were changed from the previous year. The results showed that the yield performance of each tested line varied depending on location but differed slightly from the previous year. The line UT1067B had the highest grain yield and significantly differed from the check varieties, Suphanburi 60 and Late Hegari at Banmaisamrong, Praphutthabat and Petchaboon Field Crops Experiment Station (5.59, 5.36 and 5.42 t/ha respectively). While the line UT423B had highest grain yield by about 4.39 t/ha and significantly differed from the three check varieties at Suphanburi Field Crops Research Center.

The three promising sorghum lines, UT 424-2, UT 364-2 and UT 408-1 were planted together with the check varieties in 3 farmers’ fields in a randomized complete block design with four replications. Sorghum line UT 408-1 had an average grain yield of about 3.60 t/ha which was the same as Suphanburi 1 (3.64 t/ha) and Suphanburi 60 (3.56 t/ha).

To improve high white grain sorghum yield by crossing the high and medium plant height, white and large seed size sorghum lines such as Late Hegari and Naga White with the short stemmed and creamy seed sorghum lines. Hybrid seeds of all crosses were planting in the dry season of 1995 for seed multiplication. Seed from each head of the F 1 plants were harvested and threshed separately. Seventy-three heads of eleven crosses were harvested and Pedigree selection was done on F 2 and F 3 plants in the late rainy season 1995 and 1996 respectively. Each head was planted in four rows, six meters long and 60 cm wide. After seed maturity, the heads with good appearance that were from plants which did not exceed 1.8 meters in height, were cut at the flag leaf collar and dried. Each of harvested heads were measured for peduncle length as head exertion, head width, head length, seed weight, 1,000 seed weight, peduncle diameter, days to flower, and number of seeds per head. The analysis of correlation in F 2 showed that grain yield per head positively correlated with the number of seeds per head, head width, 1,000 seed weight days to flower and threshing percentage, but negatively correlated with head exertion. In F 3 generation, Four hundred and seventy seven heads were harvested from 8 crosses. These heads had flowering dates from 45 to 55 days seed weight from 23 to 135 grams and 1,000 seed weight from 17 to 37 grams. The analysis correlation in the F 3 generation showed that grain yield per head positively correlated with head width, panicle diameter threshing percentage, 1,000 seed weight and days to flower but negatively correlated with head exertion. This was the same in the F 2 generation.

The objective of this trial was to evaluate the grain yield performance of hybrid sorghum which was crossed between introduced male sterile and improved sorghum lines. Three replications of double rows plots 6 m long and 0.6 m wide were planted at Suphanburi Field Crops Research Center in the 1995 late rainy season. The results showed that the hybrid between ICSA 42/UT408-1, ICSA 88005/UT364-2 and ICSA 42/UT 364-2 gave grain yields at about 6.46, 5.82 and 5.36 t/ha respectively. These hybrids had grain yields more than the check varieties and hybrids from the seed company, but the plant height of these hybrids were greater than the variety Suphanburi 60 and hybrids from the seed company by about 50-70 cm.

Sorghum planted during the beginning of June to the beginning of September obtained neither plant crop grain yield nor ratoon grain yield because of a mold infection. The ratoon of a plant crop planted in mid-August, gave the highest panicle dry-yield (2.1 t/ha). On the other hand, sorghum, planted during the beginning of August to mid-September were more severely infected by the leaf disease than the sorghum planted at other times.

Many factors have been recognized as the causes of poor sorghum seed quality. It is known that seed moisture content and the thresher speed are the major constrains to produce a good quality of seed. Thus, the study was conducted to investigate the optimum level of seed moisture cont and have a creamy grain color. Seed size is rather small and plant height is tall. It seem that these lines may be suitable for dual purposes.