The Relation between Length of Styles and Mendelian Segregation in a Maize Cross

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Abstract
In F2 of crosses between sugary maize and certain varieties of popcorn only about 15% of the recessive sugary is found. When the styles were cut off at the tip of the ear the percentage of su grains was significantly higher than when they extended 3 or more inches from the tip. This indicates that the growth of Su pollen tubes is faster than that of su ones. When the percentage of su grains in successive 1-inch sections of ordinary ears was determined and averaged for all ears, no consistent or progessive change was found. Individual ears frequently showed a definite trend in successive sections, but in some cases it was in one direction and in others in the opposite direction. It is therefore suggested that the growth rate of Su tubes is greater at first but is overtaken and later exceeded by that of su tubes. The effects of this would be obscured by combining all the ears. The suggestion is supported by the following facts: (a) the short ears had the highest percentage of su grains in the upper part and the long ones in the lower part. (b) In the only 4 ears in which any section has 25% su, this section is at the bottom and when all 4 are combined there is a progressive decrease toward the tip. (c) In one case in which the silk had been pollinated 8 inches from the ear, the successive sections from base to tip showed the following percentages of su grains: 35.7, 32.0, 14.8, 12.9, 12.0.