Date of Award

Winter 1991

Project Type


Program or Major


Degree Name

Doctor of Philosophy

First Advisor

Lincoln C Peirce


Large Plum', a tomato cultivar carrying a wilty mutation (LP-wilty), was characterized genetically, physiologically, and anatomically. Inheritance, complementation, and mapping studies of LP-wilty were performed. The mutation was found to be inherited as a single dominant gene, distinct from other wilty alleles, and was mapped to the long arm of chromosome six.

Measurements were taken of stomatal conductance, root conductance, shoot water potential, and leaf water potential for 'Large Plum' and normal plants. Results suggest that both stomatal conductance and root conductance rates are reduced in the wilty mutants. In addition, shoot and leaf water potentials are more negative in 'Large Plum' than in normal plants, indicating greater water deficit stress. All of these physiological tendencies are inherited in wilty F$\sb1$ plants derived from crosses between 'Large Plum' and 'Nova', a normal cultivar.

Anatomical comparisons were made between 'Large Plum' and 'Nova'. 'Large Plum' was found to have a reduced leaf hair density, abnormal root hairs, reduced leaf thickness, and altered relative volumes of cell types and air space within the leaf. All of these physical features were associated with wilting in F$\sb1$ and/or F$\sb2$ generations from crosses between 'Large Plum' and 'Nova'.