Grain Sink Size and Predisposition ofZea maysto Stalk Rot

DODD, J. L. 1980. Grain sink size and predisposition of Zea mays to stalk rot. Phytopathology 70:534-535. Corn (Zea mays) plants with rotted stalks had more kernels than populations in one location. Relationship of data to effects of rate of genetically identical neighboring plants with healthy stalks. This was carbohydrate translocation to grain and roots, including the photosynthetic observed in comparisons of adjacent rotted and healthy plants of 30 hybrids stress-translocation balance concept of predisposition of corn to stalk rots at many USA locations and in another study of seven hybrids in two plant is discussed. Additional key word: root rot. A photosynthetic stress-translocation balance (PS-TB) concept rot in the 20-cm (in-row plant spacing) plot and therefore could not of predisposition of corn to stalk rot was proposed in 1977 (2), and be compared at that plant density. for sorghum to stalk rot in 1978 (3). Development of this concept In a second experiment at five Illinois and Indiana locations, was an attempt to explain host, pathogen, and environmental observations were made of individual pairs of plants consisting of a interactions observed in the corn and sorghum stalk rots. rotted plant and an adjacent healthy plant. Each location was a Supportive evidence from the literature (2) included studies demonstration plot of adapted commercial corn hybrids on good showing: that environmental stresses reduce photosynthetic soil managed with typical, good cultural methods. Sixty-five capabilities of host plants; that stalk rot-susceptible plants have less comparisons of 30 single-cross hybrids (six seed companies reducing sugar and sucrose in the lower stalk than do the same represented) were studied. In each pair, plants with apparently tissues of resistant plants; that pith cell senescence occurs more normal, fully pollinated ears were chosen and the kernels on each rapidly in susceptible plants, that root rots precede stalk rots, and plant were counted. Student's t-test was used to analyze the data for that the Gibberella, Fusarium, and Diplodia spp. associated with pairs of plants. corn stalk rots are weak pathogens. Further support of the concept included: data showing a negative RESULTS