Comparative Efficiencies of the "Sequential Inoculation Selection" (SIS) and "Multi-Adversity Resistance" (MAR) Systems of Selection for Multiple Disease Resistance in Cotton

Ismail A. Baker and W.P. Sappenfield


 
ABSTRACT

Cotton diseases are important factors in cotton production in the North Mississippi Delta. Breeding cotton for multiple disease resistance is the only economical means to minimize losses caused by diseases. The two basic systems now in use are Multiple Disease Resistance using the Sequential Inoculation Selection (SIS) procedure and Multi-Adversity Resistance (MAR). The multiple disease resistant cultivars, Delcot 311 and CAMD-E, were crossed with Stardel, a disease susceptible cultivar, to provide segregating populations to compare efficiencies of the two systems for selecting multiple disease resistant cotton F3 plants were used to practice the sequential inoculation selection "SIS" and multi-adversity resistance "MAR" methods of selection. Progeny tests of potentially multiple disease resistant segregates were conducted on soils naturally infested with pathogens causing Fusarium wilt-root knot nematode disease complex or Verticillium Wilt.

Data summation, by analyses of variance, indicated that the "SIS" method and "Delcot 311 x Stardel" germplasm produced superior seed cotton yield, resistance to Fusarium wilt, height index, lodging index, and storm resistance index. Resistance to bacterial blight, percent germination, stand, seedling vigor, percent open bolls and days to first flower were enhanced by using the "MAR" method and "CAMD-E x Stardel" germplasm.

Significant negative simple and partial correlations obtained were between seed cotton yield and percent Fusarium wilt using the "MAR" method and "CAMD-E x stardel" germplasm; seed cotton yield and bacterial blight resistance for "Delcot 311 x Stardel" germplasm.

Step-wise regression analyses indicated that variability in percent Fusarium wilt, bacterial blight score and height index was important in accounting for variability in seed cotton yield in the "SIS" method. Percent Fusarium wilt, seedling vigor, height index, and lodging index were found to be important measurements in accounting for the variability in the yield in the "MAR" method.

Path coefficient analyses indicated a strong direct negative effect of percent Fusarium wilt on seed cotton yield in the "MAR" method and "CAMD-E x Stardel" germplasm and a strong direct negative effect of bacterial blight on seed cotton yield in the "SIS" method and "Delcot 311 x Stardel" germplasm.

Combining the attributes of the "STS" and "MAR" breeding methods should give rise to an improved method for selecting multiple disease resistant cultivars from germplasm pools of Delcot 311 and CAMD-E or lines of similar origin. A suggested procedure is presented.



Reprinted from 1985 Proceedings: Beltwide Cotton Production Research Conferences pp. 63 - 69
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998