343 



containing a large number of figures, showing the grain as affected by 

 the loose smuts, the germination of the different species of smut, and 

 the natural enemies referred to above. 



Experiments in crossing varieties of corn (pp. 288-334, illustrated). — A 

 report on an experiment in crossing varieties of dent, flint, and soft 

 corn, similar to that reported in the First Annual Report of the station 

 for 18S8, page 3 IG. Fifty-six different varieties were used, 45 of dent, 

 of flint, and 2 of soft corn. A summary of the results with each kind 

 of corn is given. The whole experiment is summed up as follows: 



Number of crosses attempted, 18S ; number of crosses successful, 175 (or 93 per 

 cent); ears too defective for comparison, 6; no evidence of cross manifest, 104 (or 62 

 per cent) ; doubtful evidence of cross, 27 (or 16 per cent) ; evidence of cross manifest, 

 38 (or 22 per cent) ; evidence in color only, 29 (or 17 per cent). Our results show in 

 common with tbose of others that the so called varieties of maize cross more or less 

 freely, and the eflects may or may not be visible the current year. * » » Here, 

 however, might be mentioned more fully the work of Dr. E. Lewis Sturtevant, as 

 reported in the New York State Statiou Report for 1884, pp. 148-1.54. Instead of 

 artificially fertilizing the pistils of auy variety with pollen from another, he planted 

 the numerous sorts of corn together, so that the pollen being distributed by natural 

 agencies might have a fair opportunity to fertilize the several varieties indiscrimi- 

 nately. He judged of the fact of crossing solely by the visible effects, and his propo- 

 sitions are based on experiments and observations extending over several years. The 

 first, namely, that maize does not in general show the effects of current cross-fertiliza- 

 tion, the exception being sweet-corn, may be said to be confirmed in part by our re- 

 sults. Yet, in case of the experiments in 18ci8, 7| per cent of the crossed ears of the 

 dent, flint, and soft varieties exhibited unmistakable evidence of the crossing, and 

 19 per cent showed the effects doubtfully. In case of the crosses made in 1889, 24 per 

 cent of the ears showed evidence of the cross and 12^ per cent were doubtful. 



Our experiments during the past two years do not show, as Dr. Sturtevant's do, 

 that the agricultural species * have a strong tendency to resist cross-fertilization with 

 eacti other. By consulting our tabulations and summaries it will be seen that dent, 

 flint, soft, sweet, and po])-corn cross as freei3' with each other as with the difterent 

 varieties in their own class. The confirmation of this statement depends in part on 

 the effects seen in the second generation (which see in the article that follows, namely, 

 Crossed corn the second year). 



According to Dr. Sturtevant, " where cross-fertilization has taken place in maize 

 the tendency is to produce both parental types, and not toward intermediates." We 

 find that the cross the first or current year is sometimes iirtcrmediate in character of 

 grains. The second year's product may show exact iuteruiediates, and in no case are 

 the ears exactly like either parent. 



In cross-fertilization variation in color is commoner than variation in other char- 

 acters. About one half of the crossed ears wliich exhibit the effect of the crossing 

 the first year show it in color only. 



With a view to improving certain leading varieties crosses of 9 of 

 these varieties were made, with a number of others, as stated in the re- 

 l)ort. The details of all the experiments in the cross-fertilization of 

 corn at the station in 1889 are given in a table which fills fifteen pages, 

 and includes the name of the variety, the date of inclosing the ear with 



* The agricultural species are given by Dr. Sturtevant as follows: Zea saccharata, 

 sweet-corn; Zea hidnrata, flint corn; Zea iiidentaia, dent corn; Zea amijUuca, soft 

 corn ; Zea everta, pop-coru. 



