New Gene Combinations Conferring Resistance to the Bacterial Blight Disease of Cotton
Abstract
F2 plants comprising different gene combinations were evaluated
for cotton bacterial blight resistance in the field of the Gezira Research Station and the greenhouse of the Plant Pathology Centre of the University of Gezira, Neshashiba, Wad Medani, during the autumn of 2002. Results generally showed significant differences between different gene combinations in resistance to the new race of the bacterium Xanthomonas campestris pv. malvacearum. Leaf disease grades ranged from 4 to 6. Most of the plants fell into grade 5. Genotype 12, with expected gene combination of (B2B3B6B7B9B12), expressed the highest level of resistance with a mean disease grade of 4, while genotypes 7, 11 and 15 showed the lowest level of resistance with a mean disease grade of 6. The results indicated the importance of the genetic background B2B3B7 in improving resistance to both the old and the new races when one of the following major genes B4, B6, B9, and B12 is incorporated. In such background, resistance level improves as the number of genes increases. Therefore, the commercial resistant cultivars having B2B6 genetic background to the old race of the bacterium can be replaced by the genetic background involving B2B3B7 in addition to one of the four major genes mentioned above in order to protect the cotton crop. Genotypes 5, 6, 12, and 19 were recommended for further improvement as they expressed relatively high level of resistance to the pathogen.
References
Proceedings of the Beltwide Cotton Production Research Conference, National Cotton Council, Memphis, Tennessee.
Bird, L.S. 1982. The MAR (multi-adversity resistance) system for genetic improvement of cotton. Plant Disease 66: 172-176.
Bird, L. S. and H.H. Hadley. 1958. A statistical study of the inheritance of Stoneville 20 resistance to the bacterial blight disease of cotton in the presence of Xanthomonas malvacearum races 1 and 2. Genetics 43: 750067.
El nur, E. 1970. Bacterial blight of cotton, pp 179-188. In: Cotton Growth in the Gezira Environment (ed. M.A. Siddig and L. C. hughes). Agricultural Research Corporation, Wad Medani, Sudan.
El-zik, K. M. and L.A. Bird. 1970. Effectiveness of specific genes and gene combinations in conferring resistance to races of Xanthomonas malvacearum in upland cotton. Phytopathology 60
441-447.
Follin, J.C., B. Girardot, V. Mangano and R. Benitez. 1988. New results on inheritance of immunity to bacterial blight (Xanthomonas
compestris pv malvacearum (Smith) Dye, races 18 and 20) in the
cotton plant (Gossypium hirstum L.). Cotton Fibers Tropicals 43:
167-174.
Hughes, L.C. 1961. A visit to the United States cotton belt. September-October, 1960. Empire Cotton Growning Review 38: 119.
Innes, N. L. 1961. Breeding bacterial blight resistant cotton in the Sudan by combining greenhouse inoculation with field spraying. Empire Cotton Growing Review 38:92.
Innes, N.L. 1964. Bacterial blight resistance breeding. Progress Reports from Experiment Stations. Republic of the Sudan. 1963- 64/ Empire Cotton Corporation, London, pp. 21-27.
Innes, N.L. 1974. Resistance to bacterial blight of cotton varieties homozygous for combination of B resistance genes. Annals of Applied Biology 78: 89-98.
Innes, N.L., S.J. Brown. and J. T. Walker. 1974. Genetical and environmental variation for resistance to bacterial blight of upland
cotton. Heredity 32:53-72.
Knight, R. L. 1946. Breeding cotton resistant to blackarm disease (Bacterium malvacearum). Empire Journal' of Experimental Agriculture 14: 153-174.
Massey, R. E. 1932. Agricultural Research Division, Sudan, Annual Report 1931/32.
Massey, R. E. 1934. Studies on blackarm disease of cotton. Empire Cotton Growing Review I l: 188.
Siddig, M. A. 1973. Barakat, a new long-staple cotton variety in the Sudan. Cotton Growing Review 50:307-315.
Wallace, T.P. and K. M. El-zik. 1989. Inheritance of resistance in three cotton cultivars to the HVI isolate of bacterial blight. Crop Science 29: 1 114-1119.
Wallace, T.P. and K. M. El-zik 1990. Quantitative analysis of resistance in cotton to three new isolates of the bacterial blight pathogen. Theoretical Applied Genetics 79: 443-448
