Abstracts Biological Sciences

Correlations between horticultural characteristics and Fusarium root-rot resistance in Phaseolus vulgaris L.: Fusarium root-rot resistance in Phaseolus vulgaris L.

by Theodora Wang

To study the association between Fusarium root-rot resistance (Fusarium solani f. sp. phaseoli) and economically inportant characteristics of beans, 2259 lines each consisting of 30 plants were used. The lines were randomly selected for root-rot reaction, but were selected for differences in vigor and differences in plant and seed pigments, growth habit, and toughness. The lines were established from crosses of resistant and susceptible parents after which self-fertilization for 4-6 generations was practiced. Measurements and classifications with respect to pigmentation, vigor and growth habits were made on plants grown in the field and the greenhouse. Toughness of pods was evaluated by means of a shear press or by subjective estimates. Replicated tests of these lines with artificially produced inocula of the Fusarium organism were made in the greenhouse and in the field, thus under different environmental conditions. Uninoculated plants of each of the lines were also grown in order to evaluate the lines simultaneously for the horticultural characters. The relationships between resistance and plant characteristics were determined by correlation analysis among the traits. Though correlation coefficients were small or non-significant in many cases, some associations were indicated: 1, Indeterminate growth was associated with low root-rot infection. 2. Late flowering was related to high susceptibility of beans grown in the field. 3. Late maturity was associated with high score for root-rot of field grown beans 4. High shear press readings were associated with low root-rot infection of field-grown beans, 5. Plants with dark colored seeds were less susceptible to root-rot infection when the beans were grown in the field.