. The effects of inbreeding and crossbreeding upon development . Ave. No. Rows of 1-7-1-1 Ave. No. Rows of 1-7-1-2 Generations Inbred Figure II. The reduction in variability and segregation of number of rows of grain on the ear in selfed strains of maize. East and Hayes ('12) have noted many characters which are isolated from maize by inbreeding. In addition to these, several other characters have been isolated in this and in other material. One of these characters is a constant difference in shade of color of the foliage—some are dark green, others are light, yellowish green. Some strains are
. The effects of inbreeding and crossbreeding upon development . Ave. No. Rows of 1-7-1-1 Ave. No. Rows of 1-7-1-2 Generations Inbred Figure II. The reduction in variability and segregation of number of rows of grain on the ear in selfed strains of maize. East and Hayes ('12) have noted many characters which are isolated from maize by inbreeding. In addition to these, several other characters have been isolated in this and in other material. One of these characters is a constant difference in shade of color of the foliage—some are dark green, others are light, yellowish green. Some strains are lacking in root development and never stand upright throughout the season. Some have a single-stalked unbranched tassel, while others are profusely branched. Some strains have' peculiarly wrinkled or wavy leaves, particularly noticeable in the first leaves. Some strains produce a small pro- portion of connate seeds similar to those observed by Kempon ('13) in nearly every ear, while their occurrence has never been observed on other inbred lines derived from the same source. There are also marked differences in susceptibility to disease as will be shown later. These illustrations are sufficient to demonstrate beyond doubt that by far the greatest amount of the fluctuating variability found among ordinary cross-fertilized plants is due to the segrega- tion and re-combination of definite and constant hereditary factors. Many of these characters are seldom seen in continually cross-pollinated plants, and never are so many combined together.
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