FIELD CROPS. 433 



and there was segregation into pointed, nonpointed, and intermediate ears in F2. 

 Tliirteen self-pollinated F: ears were grown in F3. Of these, the following F2 

 ears were classed as pure pointed (6X64) -6-6, (6X64) -6-3, (6X64)--;^8, 

 (6X64) -4-9. Two of these ears, (6X64) -6-6 and (OX 64) -6-3, bred true in 

 Fs, while (6X64) -4-8 and (6X64)-4-9 showed segregation in F3 with a total 

 of 85 pointed and 31 intermediate pointed ears. Two self-fertilized ears, 

 (6X64) -4-8-8 and (6X64) -4-8-3, were grown in 1914. One proved to be a 

 pure pointed ear and the other again gave pure pointed and intermediate 

 pointed seeds. Those results might have been obtained if ear (6X64) -4-8 

 were homozygous for one factor for point and heterozygous for a second factor. 



"Three self-fertilized F2 ears of the intermediate class shovrcd a range of 

 variation in Fs from pure-pointed to nonpointed ears. Six F2 ears classed as 

 nonpointed were proven to have been hybrids by the F3 results. One of these 

 (6X64)— 1-7, produced 52 intermediate and 13 nonpointed ears. As no typi- 

 cally pointed ears were obtained it seems fair to conclude that the parent ear 

 (6X64) -4-7 was heterozygous for one factor for pointed seeds. Two self- 

 fertilized ears F3 of line (6X64) -6-6 which bred true for the pointed habit 

 in F3 were grown in F4. Ear (6X64) -6-6-4 gave a progeny of 35 ears, all 

 of which were pure-pointed, while (6X64) -6-6-1 had a progeny of 23 pure- 

 pointed ears and four vrith points more strongly developed than the interme- 

 diate class, but not so strongly developed as the 23 pure-pointed ears." 



The White Rice pop pax-ent contains only a small amount of floury starch, 

 while the dent variety has corneous starch at the sides of the seed and floury 

 starch at the cap and next the embryo. There was no effect on the development 

 of the amount of corneous starch in Leaming dent (No. 6) due to the pollen 

 from White Rice pop (No. 64). The Fi generation cross produced ears with 

 intermediate-sized seeds. These ears would have to be classed as dents. 



"Two Fi ears (6X64)^ and (6X64)-6 were grown in F2. Both popu- 

 lations showed a wide range of variation. The ears were classed as pure dent, 

 nearly pure dent, half seeds dent, few seeds dent, and nondent. Ear (6X64)-4 

 had progeny of each class, while (6X64) -6 produced progeny in all classes 

 except the nondent class. Thirteen F2 ears were grown in Fs. Two nondented 

 ears gave a progeny of nondented ears and ears with a few seeds slightly 

 dented. No ears bred true in F3 or F* for the pure dented condition, although 

 some selections gave a progeny with a much larger proportion of dented ears 

 than others. Twelve F3 ears were grown in F4. Ear (6X64)-6-5-3 produced 

 the greater proportion of its progeny in the pure dent class. 



Tests of corn varieties on the Great Plains, L. L. Zook {U. S. Dept. Agr. 

 Bui. 307 {1915), pp- 19, figs. 4). — This bulletin contains results of varietal tests 

 of corn conducted on dry land and under irrigation at the following-named 

 stations in the Great Plains area: Huntley, Mont., Newell, S. Dak., Mitchell 

 and North Platte, Nebr., and Akron, Colo., in which several offices of the De- 

 partment and the Nebraska Experiment Station cooperated. 



Descriptive lists are given showing the dent, flint, and soft varieties of corn 

 used in the tests. Tabulated data show yields of plats at the various stations. 



The results covering the three years 1912, 1913, and 1914 have shown that 

 small differences are of importance only when it is certain that such differences 

 are due to potential varietal qualities and not chance fluctuations. It ap- 

 pears that the usual recommendation favoring locally-grown seed has in some 

 cases been overemphasized by comparing averages rather than the perfor- 

 mances of individual varieties and that to assume that a variety is best for 

 a locality because it has had an opportunity to become acclimated may be as 

 false a conclusion as to assume that a variety will do well in one locality be- 

 cause it has done so in some other locality. The range of adaptation of vari- 



