Biological studies of amaranthus viridis L. and sinapis arvensis L

Mukhtar, A.M., Sudan University of Science and Technology, Khartoum; Eltahir, S.A., Cereals Research Center, Sorghum Research Program, Wad Medani; Siraj, O.M., Cereals Research Center, Sorghum Research Program, Wad Medani; Hamada, A.A., Agricultural Research Corporation, Wad Medani

Biological studies of amaranthus viridis L. and sinapis arvensis L

2007

Mukhtar, A.M., Sudan University of Science and Technology, Khartoum (Sudan) | Eltahir, S.A., Cereals Research Center, Sorghum Research Program, Wad Medani (Sudan) | Siraj, O.M., Cereals Research Center, Sorghum Research Program, Wad Medani (Sudan) | Hamada, A.A., Agricultural Research Corporation, Wad Medani (Sudan)

A study was conducted to investigate some biological aspects of the weed species Amaranthus viridis L. and Sinapis arvensis L. Seeds were sown in field plots on 3 November 2003 at Dongla area, Northern State. At flowering plant height, root length and days to 50% flowering were recorded. At maturity number of seeds/plant was counted. Laboratory experiments included the effects of constant temperature (5 - 45°C) and alternating temperature of 30/20 °C, simulated drought (0 to -15 bar) and sowing depth (0 - 5 cm) on seed germination and seedling emergence. Germination of both species commenced within 24 h, rapidly increased after 3 days and reached a maximum with 3 _ 9 days. Both species are annual herbs 90 -92 cm high, with 22 - 30 cm root length, reached 50% flowering within 52 _ 54 days and completed their life span after 99 -101 days. A. viridis produced 1050000 seeds/plant, while that for S. arvensis produced only 650. Seed germination of both species, was inhibited at 5 and 45 °C. Germination of A. viridis occurred at 15 °C, while that for S. arvensis commenced at 10 °C. The optimum temperature for germination of A. viridis was at 30 or 30/20 °C, while that for S. arvensis was 20 °C. The maximum temperature in both species was 40°C. Germination decreased with increased osmotic pressure. In A. viridis seeds it took place at _3 and _6 bar, while that of S. arvensis was displayed up to _12 bar. Germination was considerable (94-99%) at sowing depths of 0 - 2 cm, moderate (70-88%) at 3 cm depth and was significantly reduced at 4 and 5 cm depth. Seedlings failed to emerge at 4 or 5 cm depth. Maximum emergence was attained at 0 - 0.50 cm depth. Emergence of A. viridis was generally higher than S. arvensis

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