FIELD CROPS. 229 



The failure of 43 per cent of tlie plants of the seconcl generation of tliis 

 cross to mature under the existing climatic conditions was the instigation to 

 perform an experiment based upon automatic elimination of weak plants. The 

 beans were planted in a young sorghiim field where the struggle for existence 

 was strong enough to crowd out the weak plants. The observations and discus- 

 sions in this paper have to do chiefly with the survivors of the difl:erent groups 

 with respect to the relation between the vigor of the various plants and their 

 dominant or recessive characters. In the selection of the seeds of the second 

 generation for this planting, frosted pods, low yields, and stinging hairs were 

 characters upon which rejection was based. 



It is noted that among the first 1,100 seeds, only oncrtenth of the young 

 plants survived to maturity, and out of 6,093 seeds only 740 surviving plants 

 bore pods. On the whole, there appeared to be a selective elimination of plants 

 with certain recessive characters. This elimination caused the surviving off- 

 spring in any family to mostly resemble their parent, and often concealed the 

 fact of gametic segregation. There was evidence that the recessive character 

 of black shoots and smooth pods was accompanied by less vigorous growth. 

 The differences of pod lengths in the different parents were mostly repeated in 

 the third generation. The high breadth-length index of the seeds of many 

 plants was probably, in great part or wholly, determined aiechanically by the 

 shortness of the pods, and the consequent pressure on the growing seeds. In 

 the third generation the seed shape was obviously inherited in the majority of 

 the surviving progeny of each family. 



Further work in progress with crossing flint and dent corn to secure a type 

 more adapted to Florida conditions (E. S. R., 25, p. 436) is noted. 



Effects of cross-pollination on the size of seed in maize, G. N. Collins and 

 J. H. Kempton iU. 8. Dept. Agr., Bur. Plant Indus. Circ. 12Jt, pp. 9-15). — This 

 paper reports the results of cross-pollinating varieties of corn, including Mis- 

 souri Cob Pipe, Gracillima, Variegated, Hickory King, Mexico Black, and 

 Algeria. Pollination was performed in such a way as to utilize the principles 

 of xeuia to detect the pure and hybrid seeds on the same ear for comparison. 

 The silks of white-seeded varieties were dusted with a mixture of pollen of 

 the same white variety and pollen of a different variety cf colored seeds, thus 

 producing pure and hybrid seeds on the same ear. 



In every instance the size of the seed was materially increased by the for- 

 eign pollen, the increase ranging from 2.8 to 21.1 per cent. It was noted that 

 the rate of increase bears no direct relation to the size of seed in the variety 

 used as the soui-ce of pollen. No differences in specific gravity of pure and 

 hybrid seeds from the same ear could be detected. The author points out that 

 the increase in weight of the seeds thus secured may b'> due to the stimula- 

 tion by foreign pollen, and has more than scientific value. 



Corn production, O. D. Center {Ann. Rpt. III. Farmers'' Inst., 16 {1911), pp. 

 9-'t-102). — The author in this address points out the difference between mainte- 

 nance production and profitable production. He considers vegetable matter in 

 the soil the chief factor of large crop production, with crop rotation with a 

 legume as the foundation, and its proficiency based upon the lime content. 



Grow corn tliat will ripen, J. H. Shepperd {Wallaces' Farmer, 38 {1913), 

 No. 12, p. i)Jf5). — In this article the author emphasizes the impoi-tauce of plant- 

 ing a variety of com that will surely ripen, quoting analyses by the North 

 Dakota and New York State stations showing the increased digestibility at 

 maturity. He considers it a mistake to grow corn, even for silage, that will not 

 reach the gl:i/aug stage of growth before there is danger of killing frost. 



The wild prototype of the cowpea, C. V. Piper {U. S. Dept. Agr., Bur. Plant 

 Indus. Circ. 124, PP- 29-32). — This paper continues the discussion of the origin 



