Experiment to Influence of planting date on growth and allelopathic of sesame on subsequent crops. The month of planting affects the growth and yield of sesame CM-07 and CM-53. Sesame is planted in June, with the best growth and maximum yield. Different from planting in November. Growth and low productivity. Efflorescence showed sesame is grown in October-December early flowering is 32 days from planting to flowering so. The sesame seeds are planted in June-July is 37 days from planting to flowering. After harvesting sesame and incorporation of sesame soil left for one month and then plant corn, sorghum and sunflower. The plots are planted sesame seeds before planting the crop yield has less volume than in plots that did not have sesame seeds before planting. The sunflower is a plant that has been most influenced by Sesame. Sesame is grown in June, containing allelopathic than in other months. Sesame is grown in November the lowest allelopathic.

Abbreviations: CM-07: Black sesame shattering resistance and CM-53: White sesame shattering resistance

Cropping system shares a large 2 system is Mono Cropping and Multiple Cropping may crop once or more than 1 time in the types of plants that grow more than 1 time in the kinds of plants that grow more than one type of composite form. Planting is different crops. (Intercropping) crop margins season (Relay Cropping) Crops Rotation crop mix (Mixed Cropping) and cropping sequence (Sequential Cropping) is cropping up in various forms received. Coupled with the development of the various factors involved, such as maintaining soil fertility, soil structure, and nutrient selection of suitable plants. Factors including the Allelopathy, which is another factor that is vital to the development of the crop (Hanvongsa, 1999). The allelopathy has allelopathic compounds, which means that the plant is well. Microorganisms drive out to certain substances affects the growth of plants is another. Passengers may inhibit or encourage, directly or indirectly, any delay or accelerate the direct or indirect. But the plant is not harmful (Molish, 1973) Allelopathic substances that accumulate in the soil may be due to the release from the roots and stems of plants directly. Or from the decomposition of crop residues remaining residues in the soil. As a result, either to inhibit or stimulate the growth of plants that is cultivated or planted close together after the next (Rice, 1984: Waller, 1987).

The compounds that inhibit or stimulate the growth of plants depends on the concentration of substances dissolved in the soil. Allelopathic effect of which is classified as one of the factors related to the environment that influences the division of the plant, including cultivated crops allelopathic occurs. In addition, the plants also affect weeds (Rice, 1979). Effect on seed germination and growing plants. Including crop yields. In the cropping system allelopathy has been studied between plant and plant to find ways to utilize the improvement in cropping systems to increase productivity and lower costs of harm to the environment. Sesame oil is important to Thailand. High potential for market competition and farmers planted crops in cropping system. The production of sesame in Thailand it is not enough for the needs of both domestic and international markets. The demand is increasing every year. Due to low yield and quality one of the limitations is the lack of understanding about technology (Kerdphol, 2001). Varieties and season planting have a great impact on the growth and yield of sesame (Maneekaw, 1996; Tiangtrong, 1998). Although the recommended planting season is generally early in the rainy season (February-April) and the rainy season (July-August), but also the right time to plant vary from each local area. (Sakunruk and Wasana, 2001) Also allelopathic in sesame can affect the growth of crops. The research of Premasthira (1988) found that white sesame inhibited the growth of both grain and grass Rice giant mimosa. It will enable the length and root length decreased.

The problem, therefore, this research has objectives to study the growth characteristics of CM-07 and CM-53, when planting with different times and study the allelopathy effects of sesame on later planted cropping systems includes evaluates allelopathic effects of sesame seeds grown during different periods of time.

This study investigated the allelopathy of sesame in cropping system in the transplanted condition. Sesame is the main crop grown in the first season and three secondary crops, corn, sorghum and sunflower, are planted with the second growing season. The procedures were planned with the following.

In the first year of planting sesame in field of the farmer at Khok Samrong district Lopburi. Sesame planting with the 10^th of April 10^th of May 10^th of June 10^th of July 10^th of August and 10^th of September. The experimental design was RCBD with 4 replications planting sesame seed variety CM-07 and CM-53. Size of plot size 19.5 x 40m. Distance between rows 75 cm. The distance between trees 20 cm. 3 seeds per hole. When sesame was 2 weeks old make a withdrawal of 1 tree per hole, water daily sprinkler system, rid of weed every 1 month. Harvest of seed at 100 days after the harvest already. Sesame plowing into the ground, leaving one month for sesame is fully decomposing. Data collection days to germination, days to 1^st flowering, plant high (cm.), branches/plant capsules/plant and grain yield (kg/rai).

In the second year experiment in the same area sesame seeds were planted before that has been plow sesame compares with other plots that did not plant sesame before planting. Prepare the same planting as the first year of planting, the row of the second season must match the same row of the first growing season. Sow the seeds of three test plants at the spacing of planting, sunflower, sorghum and maize together in one main plot. Make all 4 mains plot. Total area of 19.5 x 40m². Corn and sunflower the distance between tree 20 cm, the distance between rows 75 cm, 3 seed per hole. Sorghum is sprinkled in rows of rows, 6 meters wide and 10 meters long distance between rows 75 cm. The plot was not planted sesame before use planting area 19.5 x 10m² the experimental design was split plot design with 4 replications. Water daily sprinkler system, rid of weed every 1 month. Harvest the seed yield of each test crop according to the harvesting period of plants. Data collection days to germination, days to 1st flowering, plant high (cm.), branches/plant capsules/plant and grain yield (kg/rai). Recording except the guard row randomly collects 10 samples. Data collection corn: seed row/ear, no. seed/row and grain yield (kg/rai) sorghum: seed weight/panicle (g), seed weight total (g) and grain yield (kg/rai) sunflower: Width of disk flower (cm) Weight of disk flower (g) and Seed weight/disk flower (g). Data analysis brings characteristics information about the collection to analyze the variance and compare the mean difference by Duncan's Multiple Range Test (DMRT)

The results show of sesame seeds planted in June is the best growth and yield to sesame seed is CM-07 height 112 cm. The branches 4 branches, capsules per plant and yield 109 capsules and 347.13 kg/rai respectively [Table 1]. The white sesame seeds CM-53. 107 cm height, number of branches 4 branches, capsules per plant and yield 101 capsules and 325.54 kg/rai respectively [Table 2] quantity reduce when planting after that. Sesame seeds planted in November, the lowest growth and productivity of sesame seed is the most CM-07 76 cm height, number of branches 3 branches. 65 capsules per plant and yield 198.65 kg/rai, the sesame seed CM-53 72 cm height, number of branches 3 branches. Capsules per plant and yield 63 capsules and 187.62 kg/rai. White sesame varieties CM-53 is affected from effect of planting date more than black sesame varieties CM-07.

The flowering was found that the sesame planted in October-December flowering is the fastest flowering is 32 days from the plantation to flowering, the sesame seeds planted in the June-July period 37 days from planting date, then flowering. The flowering age when grown in October-December flowering is faster than planting in June and July 5 days. After harvesting sesame seeds and sesame plowing into the ground, leaving one month and then plant corn, sorghum, sunflower behind the plots it found plots are planted sesame before had lower yield plots are not planted sesame before. Sunflowers are the most influenced by sesame, with the lowest productivity compared with plots are not planted sesame before, there is a width of disk flower 12.15 cm weight of disk flower 1.43g and seed weight per dish flower 47.5g while plot are not planted sesame before has width of disk flower 15.52 cm weight of disk flower 1,629.4g and seed weight per dish flower 53.8 g (Table 5) corn and sorghum production decreased compared to the plots that do not have sesame before. Corn planted after the sesame plantinghas seed row/ear 11.58 no. seed/row 21.67 and grain yield 271.58 kg/rai but corn is not planted in plots with sesame seeds before planting has seed row/ear 14.58 no. seed/row 24.17 and grain yield 946.46 kg/rai. Sorghum found plots is planted sesame before to seed weight/panicle 14.82g seed weight total 328.5g and grain yield 133.48 kg/rai, which is less than plot are not planted sesame before to seed weight/panicle 34.16 g seed weight total and grain yield 765 grams and 310.86 kg/rai respectively. [Tables 3 and 4] which corresponds to Sakunruk and Wasana (2001) reports that, when cultivated Sesame June 20 with the best growth and keep maximum productivity and decreases as the sequence when planted after June.

Sesame seeds are planted in October, the flowering period of 6 days faster with shorter 8 day height. Number of pods per ton and decreased yield of Kerdphol (2002), reported that tropical crops like Sesame, hot and sunny. Optimum temperature for growth of approximately 27-30 degrees Celsius. Don't like the cold. If, the temperature is lower than 20°c. Germination is slow or possibly halt the growth, but if the temperature is higher than 40 degrees Celsius, it will make it difficult to create stick-pollination as pods. Usually in the rainy season, there will be sufficient moisture for growing season cultivated sesame. But if grown in the dry season, although like the hot weather and withstand drought well enough. If the output is high, like irrigation water in because of the water, not too much will affect the growth of sesame. Sesame seeds planted in June, there are allelopathic more planted in other months the sesame seeds planted in November substance allelopathic lowest.

Since June sesame has maturation have branches. The high and the number of pods per plant as much as possible. So it is the production of out more planted in other months Especially in November. Which has the highly retarded the lowest. The yield of crops grown after sesame cultivation in June produced the lowest. The November yield. The allelopathic created with many factors, such as light, nutrient deficiencies, lack of water, the temperature Allelopathic agent plant age, heredity, prey and predators. (Einhellig, 1987), and Premasthira and Zungsonthiporn (1995) extract from Sphenoclea zeylanica Gaertn with methanol and then tested for seedlings of rice found when the vegetable fields it contains lung age highly retarded to increase.

Black sesame shattering resistance varieties CM-07 and white sesame shattering resistance CM-53 look close growth both days of germination, flowering and plant height, number of branches per plant and number of pods per plant, the growth and High yield in June. The November growth and yields are low. Planting corn, sorghum, sunflower, behind sesame cultivation decrease the growth and yield. Sesame seeds planted in June there are highly retarded more planted in another month. The sesame planting months November contains highly retarded the lowest.