10181 HORTTCULTUUE. 445 



lighted crop was of good quality, and the no-light crop was long-stemmed, 

 watery, and subject to disease attack. Celery grown at 80° F. was shorter and 

 far more leafy than that grown at 60° but Its quality was not injuriously 

 affected. 



It Is pointed out that blanching, if properly done, tends to develop a nutty 

 flavor ; if improperly done, a bitter flavor. In either case the chlorophyll is 

 profoundly modified or destroyed. Reference is made to experiments con- 

 ducted at the Maryland Station in which it was shown that pithiness, which is 

 characterized by lack of parenchyma, is due in the self-blanching varieties to 

 heredity, to the propagation of an undesirable strain, or to reversion, but that 

 in other forms of celery it is quite as likely to be due to unfavorable cultural 

 conditions. Careful seed selection, it is believed, should to a large degree ob- 

 viate this difliculty. 



Breeding sweet corn resistant to the corn earworm, G. N. Collins and J. H. 

 Kkmpton ([/. S. Dcpt. Agr., Jour. Agr. Research, 11 (f017). No. 11, pp. 549- 

 572). — Observations made by O. F. Cook on a variety of field corn growing near 

 Rrownsville, Tex., indicated that the greater Immunity of southern varieties 

 of field corn to depredations of the corn earworm may be due to the greater 

 development of husks in these varieties as compared with northern varieties. 

 Breeding investigations were started in 1912 by J. H. Kinsler with the idea that 

 the special susceptibility of sweet corn varieties to attacks of the corn ear- 

 worm may not be due to the character of the seeds alone. Crosses were made 

 between three commercial varieties of sweet corn, Stowell Evergreen, Early 

 Evergreen, and Early Cory, and two varieties of field corn, Brownsville and 

 Marrainto. The work of breeding and selection was continued by the authors, 

 and a biometric study was made of characters believed to be associated with 

 worm resistance. Earworm resistance was tested in 1915 near San Diego, Cal., 

 and in 1916 near Washington, D. C. The results of the investigation are here 

 tabulated and discussed in detail. 



The progeny of these crosses have been found to be much less subject to in- 

 jury from the corn earworm than commercial sweet varieties, and the data 

 seciu-od indicate that the factors concerned in immunity are inherited, and 

 thus capable of improvement. Of the characters measured, prolongation, or 

 the extent to which the husks exceed the ear, was found to be the most closely 

 correlated with low damage. Thickness of the husk covering was associated 

 with low damage to some extent, but only 5 per cent of the larvre that reach 

 the ear bore through the husk. The occurrence of leaves on the husks ap- 

 peared to attract the moths or, at least, to afford a location for the eggs. Cer- 

 tain recorded differences between the inter and intraprogeny regression are 

 believed to indicate that the protection is in psLTt due to other characters cor- 

 related with husk prolongation and not included in those measured. It was 

 found that in the more immune progenies both the number of larvse and the 

 damage per larva were low. It is suggested that at least part of the immunity 

 may be due to the presence of some volatile substance distasteful alike to the 

 moth and larvse. This was not noticeable in the ear, for when gathered at the 

 proper time the immune strains were pronounced by a number of different ob- 

 servers to be fully as sweet as the parent sweet varieties. 



" From the experiments here reported it appears that by increasing the 

 length and thickness of the husk covering and reducing the husk leaves varie- 

 ties of sweet corn can be produced in which damage from the corn earworm 

 is materially lessened. No difficulty was experienced in securing by hybridiza- 

 tion and selection the desired plant characters in combination with the seed 

 characters of sweet corn." 



