1919] FIELD CROPS. 235 



Cook proved to be the most wilt-resistant strains tested, while Wannamaker- 

 Cleveland was found to be somewhat wilt-resistant. 



Continued observations on the single-stalk method of cotton culture are said 

 to indicate that increased yields obtained in some cases by this practice were 

 due to close spacing rather than to delayed thinning. Spacing experiments 

 again resulted in the highest yields being obtained from close spacing. 



Fertilizing cotton at the Holly Springs substation is said to have given good 

 returns on the investment over a period of 12 years. 



Much variation was observed in the number of flowers produced by different 

 varieties, but in general it was noted that varieties producing and supporting 

 the most flowers during the first part of the fruiting season were the most 

 satisfactory for growing under weevil conditions. Selected strains developed 

 by the station comprised a majority of the ranking varieties in all the tests. 



A study of certain environmental factors and varietal differences influ- 

 encing the fruiting of cotton, E. C. EwTNG (Mississippi Sta. Tech. Bui. 8 

 (1918), pp. 95, fi(is. 40). — Observations of the fruiting processes of American 

 upland cotton, including flowering, shedding, the effect of removal of flowers 

 ui ion fruiting, and the developmental period of the boll; and of varietal dif- 

 ferences in the fruiting processes are discussed in considerable detail. The 

 seasonal history of the cotton plant, the nature of boll-weevil injury and the 

 problem of its control, and the relation of early maturity in the cotton plant 

 to weevil injury are described. The discussion and the conclusions reached 

 are based chiefly on a statistical analysis of data collected in the field in con- 

 nection with cotton variety tests made at Agricultural College during 1911, 1912, 

 and 1913, and at Holly Springs during 1914. In 1913 and 1914 meteorological 

 instruments were exposed during fruiting season, aud the records obtained, 

 together with daily soil moisture determinations, were used in an effort to 

 study the relation between the diurnal fluctuation in flowering and shedding 

 and environmental conditions. 



Neither soil moisture nor air temperatures appeared to be constant con- 

 trolling factors in the daily fluctuations noted in flower production, although at 

 times they seemed to act as limiting factors when their values became abnormal. 

 Nevertheless the sharp variations observed in flowering are thought to point 

 to the existence of definite environmental relations, however obscure they may 

 be. 



The water content of the plant appeared to have an important influence upon 

 shedding, a deficient supply of moisture resulting in excessive shedding. Varia- 

 tions in soil fertility did not seem to greatly disturb the ratio between the 

 amount of flower production and of fruit maturing therefrom. It was concluded 

 that in general shedding was not greatly affected at time of flowering unless 

 pollination was interfered with. Observations upon the relations between 

 flowering and shedding and the several environmental factors have led to no 

 definite conclusion. 



It is stated that the cotton plant naturally produces a surplus of flowers, 

 many more than can be matured into fruit, and that the elimination of a large 

 part of these always occurs, regardless of how favorable the conditions may be 

 under which the plants are grown. 



The relations between the boll period curve and the temperature curve are 

 deemed very significant. The average daily temperature prevailing through- 

 out the developmental period of the bolls resulting from the first two weeks 

 of flowering was approximately S0° F. at the beginning and 70° at the close. 

 The condition of the soil, including texture, moisture, and fertility: the 

 humidity; and the age of the plant are all said to have influenced the length 

 of the time required for the boll to mature. It is regarded as certain that the 



