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The Journal of Heredity 



what flattened spheres, those derived 

 from thicker discs not showing such 

 flattening. In addition to the single 

 large factor which causes the difference 

 between sphere and disc shapes, there 

 seem other independent factors which 

 affect fruit shape in the same general 

 way but to a slighter degree. 



The great variety of other fruit 

 shapes in the summer squash is doubt- 

 less due to many other factors, and a 

 more complete analysis of the problem 

 of fruit shape in these plants has been 

 undertaken. 



FLESH COLOR OF FRUIT 



Considerable difference exists be- 

 tween the various pure lines as co the 

 flesh color of their fruits. In some, this 

 is pure white, the seed cavity and pulp 

 having a slight greenish tinge. In 

 others it is cream with yellow pulp, and 

 in a few it is a deeper cream with a 

 hint of reddish, the pulp being salmon. 

 In plants with yellow fruit, the flesh 

 color is almost invariably cream or 

 salmon, but white fruits may have 

 flesh of any color. The extremes of 

 color are readily distinguishable, but 

 they grade into one another in such a 

 way that the intermediate forms are 

 often hard to classify. 



During the course of inbreeding, 

 cream fleshed plants have several 

 times arisen from white fleshed ones 

 and subsequently bred true. No 

 instances have been found, however, 

 of a white fleshed type originating 

 from a cream fleshed family. 



Figures as to the inheritance of flesh 

 color in seven crosses are set forth 

 in Table V. 



In the first four of these, white is 

 clearly dominant and seems to differ 



from cream by a single factor, the F2 

 approximating three whites to one 

 cream. In the last three pedigrees, 

 however, the dominance of white is 

 not so complete, for although the Fi 

 is here recorded as white, the white 

 has a very slight creamy tint. In these 

 pedigrees, also, white and cream occur 

 in about equal numbers in F2. In these 

 cases it is noteworthy that the cream 

 fleshed parent was a yellow squash, 

 whereas in the first four pedigrees it 

 was a white squash. Flesh color 

 evidently behaves differently in differ- 

 ent cases, and we may perhaps assume 

 the operation of two different kinds of 

 factors for cream, as well as of factors 

 modifying the intensity of the color. 



BLOSSOM END 



Plants differ markedly in the size and 

 character of the scar at the blossom end 

 of the fruit where the corolla fell off. 

 This may be large or small, shallow or 

 deep. Perhaps the most striking 

 difference, however, is that between the 

 single (Fig. 18, 85BS1-4), and the 

 double (Fig. 18, 8BS2-5), the scars 

 of the stigma and of the corolla 

 being united in the former and sepa- 

 rated by an area of smooth pericarp 

 in the latter. 



Pure lines differ in the character of 

 the blossom end, some being invariably 

 single and others always wide and 

 double. Certain lines, however, are 

 intermediate, some plants being single 

 and others narrowly double with only 

 a small smooth area between the scars. 

 The two types may even be found on 

 different fruits of the same plant, and 

 the character is thus probably easily 

 susceptible to environmental differ- 

 ences. During inbreeding, single types 



Table V. Inheritance of Flesh Color in Fruit 



