538 



The Journal of Heredity 



A CABBAGE CHIMERA 



Variegated cabbage, whose heredity has not yet been put to the test of breeding. Dr. Chapin 

 thinks it is probably a chimera showing both sectorial and periclinal variegation. (Fig. 12.) 



plants which act as hcterozyj^otes ; that 

 is, they ])roduce green scedHngs and 

 white scedHngs in the ratio of 3 : 1. 

 Such plants have been reported by 

 Baur (6) for Antirrhinum (Snajxlrag- 

 ons) and Melandrium. Johannscn has 

 also bricflv rc])ortcd a similar case in 

 Phascolus"( Kidney Beans). Shull (16) 

 has confirmed Baur's work with Mclan- 

 driiun. 



Baur's Melandrium (6) is especially 

 interesting. He fovmd a wild Melandri- 

 um album which had one branch with a 

 streak of white tissue on it affecting 

 the leaves on that side. Eventvuilly the 

 white tissue surroimded the green, fonn- 

 ing a periclinal chimera with white- 

 edged leaves. A female blossom on this 

 V)raneh was then fertilized with ])ollen 

 from a normal green ])lant. This was 

 equivalent to a cross between white 

 female and green male since the genn 



cells are only formed from the outer 

 layer of cells just beneath the epidermis 

 in the apical cone. This cross resulted 

 in over 200 seedlings all green though a 

 little ])alcr than nomial. When crossed 

 with each other the\- ])roduced green 

 and white offs])ring in the ratio of 3 : 1. 

 No \'ariegated j^lants were produced. 

 The question then was whether the 

 white branch had si^rung from a normal 

 green ])lant or from a hetcrozygote for 

 white and green. As self fertilization 

 was impossible, flowers on the green 

 branches were crossed witli pollen from 

 heterozygotic offspring oi tlie white 

 branch, ])roduced as described, with 

 the result that green and white seedlings 

 were ])rodueed in the ratio of 3:1. If 

 the jjlant ha<l been a normal green 

 homozygote such a cross would have 

 produced onh'^ green plants. 



