SUSCEPTIBILITY OF DENT CORN TO" ROOT ROTTING. 



Table 1. — Infection, by rot-producing organisms in starchy and in horny ears 

 of several varieties of dent corn obtained from different parts of Indiana 

 during 1918 and 1919. 



Source of sample 

 (Indiana). 



Variety. 



Average 

 character. 



Number of ears studied. 



Infected ears 

 (percent). 



Total. 



Starchy. 



Horny. 



Starchy. 



Horny. 







F 

 F 

 D 

 E 

 E 

 E 

 E 

 E 

 E 

 D 

 D 

 D 

 C 

 E 

 D 

 D 



100 

 100 

 100 

 100 

 150 

 100 

 100 

 100 

 100 

 100 

 100 

 150 

 200 

 100 

 400 

 100 



42 

 24 

 40 

 44 

 42 

 22 

 15 

 24 

 37 

 59 

 34 

 52 



168 

 53 



304 

 54 



58 

 • 76 

 60 

 56 

 108 

 78 

 85 

 76 

 63 

 41 

 66 

 98 

 32 

 47 

 96 

 46 



6.17 

 58.33 

 57.89 

 50.00 

 50.00 

 20.00 

 42.86 

 50.00 

 43.75 

 46.20 

 76.92 

 68.40 

 70.33 

 66.67 

 55.27 

 51.56 



4.45 







43.24 





Early Yellow Dent 



17.59 





33.33 





Reid Yellow Dent 



...do 



28.57 





16.50 





do 



35.00 





do 



23.08 





do 



37.04 





do 



38.90 



Delphi 



do 



41.67 





do 



47.20 





. ...do 



35.29 



Shelbvville 



Johnson County White. . 



58.33 



Do 



41.67 





. ...do 



34.78 









Total 



2,100 



1,014 

 63 



1,086 

 68 













50.90 



33.54 













In every case the ears of the starchy class were characterized by a 

 larger percentage of infections. This was especially noticeable in 

 those strains which averaged a half (C) or a quarter (D) starchy. 

 A very horny sample from Woodburn, Ind., carried a very low 

 amount of ear infection. In this sample the differences between the 

 horny and starchy groups were practically negligible. The most ex- 

 treme difference occurred in a lot of starchy ears of Reid Yellow 

 Dent from Xew Richmond, Ind. In this lot 70.33 per cent of the 

 starchy ears were infected, compared with only 35.04 per cent of the 

 horny ears. In general, such extreme variations have not been en- 

 countered. When all the samples subjected to this germination test, 

 totaling 2,100 ears, are considered together, practically equal num- 

 bers of horny and of starchy ears are represented. The average 

 proportion of infection in the horny group was 33.5 per cent and that 

 in the starchy group 50.9 per cent, representing 17.4 per cent fewer 

 infected ears in the horny group. 



These data indicate that progress may be made in securing better 

 seed ears by selecting those ears within the strain which have the 

 more horny composition. 



Though these data concerning car infections of different varieties 

 are meager, it is evident from the variations encountered among the 

 nine separate strains of Reid Yellow Dent under comparison that as 

 great variations in the character of the endosperm may occur among 

 Strains afi among distinct varieties. The field performance of these 

 indicates further that just as large variations in slarchiness 

 may occur among strains within a variety which require (ho same 



length of growing seat on. 



