Vererbung, Variation, Mutation. 167 



409) Ball, E. D., Turpin, Geo. and Alder, Byron. A Study in Annual 

 Egg Production. In: Utah Agr. Expt. Sta. Bull. No. 135, S. 1—43, 

 July 1914. 



In this work on annual egg production (fecundity) in the domestic fowl 

 the authors summarize their results as follows: The six flocks of hens under con- 

 sideration in the experiment ränge in age from seven years down to one year. 

 They are all descended from a small number of individuals introduced into the 

 poultry plant some nine or ten years ago. Taken as a whole, these flocks are 

 practically unselected as far as egg production is concerned. They have, however, 

 always been severely selected for vigor and in a few cases some of the lower 

 producers have been discarded, but in every case some have been retained. The 

 average productive life of this strain of fowls appears at the present time to be 

 about four years. The average first year production of all flocks was 124 eggs. 

 The average second year production was exactly the same as the first, while the 

 average of the third year was only one dozen less. The normal Variation in first 

 year flock averages of this strain of fowls is apparently between 100 and 160 

 eggs, the second year between 105 and 140, and the third year between 100 

 and 130. After that the average for all ages has been very close to 90 eggs per 

 year. There appears to be a fairly definite potential laying capacity for a flock 

 of this strain of fowls which finds expression in the first three years. The total 

 production of a flock for the first three years appears to be the same regardless 

 of whether the first year record was extremely high, extremely low, or medium 

 in amount. In the flocks making low first year records the second and third year 

 records were high and there was little difference in production in these two 

 years between the high layers and the low layers of the first year. In the flocks 

 making high first year records the second and third years' records were low but 

 the higher layers of the first year continued to be the highest producers. The 

 ten hens making the highest second year's record gave a higher three year total 

 than the ten making the highest first year record. Pearl. 



410) Piper, C. T., Evans, Morgan W., McKee, Roland and Morse, W. J., 



Alfalfa Seed Production: Pollination Studies. In: Bull. U. S. Dept. Agr. 



No. 75, S. 1—32, Apr. 8, 1914. 



Alfalfa flowers remain fully susceptible to pollination from the time of opening 

 until the petals wither. Pollination is ordinarily affected when the elastic stamineal 

 column has become "tripped". Flowers tripped artifically, and therefore self-pollina- 

 ted, set pods freely. The pods from artificially tripped flowers contained an ave- 

 rage of 1.72 seeds each, while those from naturally tripped flowers averaged 2.22 

 flowers each. Pollination from a different flower on the same plant is no more 

 effective than self-pollination, but pollen from another plant increases both the 

 Proportion of pods set and the number of seeds per pod. It makes but little 

 difference whether the pollen parent be the same or a different variety. Tripping 

 in alfalfa flowers may be automatic or may be effected by insects and other external 

 agents. There is a wide ränge of variability in alfalfa plants as regards the readi- 

 ness with which the flowers become tripped, either automatically or by the aid 

 of external objects, and also in their ability to set fruit when tripped. Automatic 

 tripping takes place most frequently in hot sunshine. Humidity is doubtless a factor. 

 Insects are the natural agents of cross-pollination in alfalfa, but even where they 

 are scarce good crops of seed may be produced. Automatic tripping with conse- 

 quent self-pollination probably results in the setting of an many pods as does 

 tripping by insect visitors, at least in the West, Pearl. 



