ABSTRACT
A factorial experiment with six replications was conducted in a temperature controlled water bath tank (66+1 F) to evaluate host reaction to Pythium ultimum and Rhizoctonia solani. The four factors were: Cultivars, isolates of each pathogen, inoculum densities, and planting depths. Six cultivars were used, three were developed in the multi-adversity resistance (MAR) program (Tamcot CAMD-E, Tamcot Cab-CS, and TX-LEBO-3-80), and the other three were non-MAR cultivars (Dixie King II, Lankart 57, and Westburn M). The two P. ultimum isolates were B6-1 from Tennessee and TX-1 from Texas, and the R. solani isolates were F366 from California and TX-MAR from Texas. Inoculum densities were 60 and 90 propagules/g of soil for P. ultimum and /100g of soil for R. solani, and planting depths were 0.5 and 1.5 inches. Traits measured were coefficient of velocity of emergence, emergence, seed rot, pre- and post- emergence damping-off, stand, root length, seedling height,and hypocotyl and root lesion grade.
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