The relation of seminal roots in corn to yield and various seed, ear, and plant characters

1. The number of seminal roots varies significantly with position of the seed on the ear and with differences in temperature and moisture during germination. 2. Each ear has relatively the same average number of seminal roots under different conditions. 3. The average number of seminal roots per ear is constant within the limits of sampling error under uniform conditions of germination. Samples of 20 seeds each were found to be adequate for determining the number of seminal roots under uniform conditions. 4. Number of seminal roots proved to be independent of length, diameter, or shape of ear, number of rows of grain, and length, width, degree of denting, appearance, or specific gravity of the seed. Ears with no discoloration of the shank had a slightly higher number of seminal roots than ears with discolored shanks. 5. No correlation was found between seminal roots and yield in four tests. A barely significant correlation of 0.21 was found in a fifth test. Coefficients of determination indicate that from 0.76 to 2.29% of the variation in yield is accounted for by variation in number of seminal roots. 6. Number of seminal roots was positively and significantly correlated with vigor of seedlings when the seeds were germinated between blotters and transplanted to soil, but negatively and significantly correlated when the seeds were planted directly in soil. 7. Number of seminal roots proved to be independent of date of silking, height of plant, height of ear, number of tillers, percentage of fallen plants, and percentage of smut-infected plants. A slight association between number of seminal roots and number of nodes of the progeny plants was indicated. 8. Five generations of self-pollination in four strains resulted in a marked and progressive reduction in number of seminal roots. 9. It is concluded that number of seminal roots is of no value as a criterion for selection of productive seed ears under the conditions represented by this experiment.