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Resistance to bacterial blight of cotton varieties homozygous for combinations of B resistance genes
Author(s) -
INNES N. L.
Publication year - 1974
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1974.tb01489.x
Subject(s) - inoculation , biology , blight , resistance (ecology) , bacterial blight , gene , sheath blight , horticulture , high resistance , plant disease resistance , agronomy , botany , genetics , rhizoctonia solani
SUMMARY In the Sudan, inoculation experiments were done on a wide range of Egyptian cotton lines homozygous for single genes and for digenic and trigenic combinations of Knight's B genes for resistance to bacterial blight. Although leaf inoculation was successful, stem inoculation was only partially so and boll inoculation, using two different techniques, failed to produce measurable disease symptoms. There was a good general relationship between leaf and stem resistance, and a close association between resistance to natural attack in the field and leaf resistance to artificial inoculation. Confirmation was obtained of the strong resistance conferred by B 2 B 9K , which was as effective as B 2 B 6 or B 2 B 3 B 6 . No other combination was as effective when inoculated artificially. Nevertheless, in a natural field attack, only mild symptoms were found in lines homozygous for B 1 B 9K and for B 4 B 6 . Under the same conditions lines with B 2 B 6 showed no symptoms but those with B 2 B 3 were severely attacked. Reasons for continuing to use major genes in the breeding of blight‐resistant cotton in the Sudan are discussed.