52 DEPARTMENTAL REPORTS. 



stations have recently shown the protein, starch, and fat contents of 

 corn to be subject to great variation in different individuals and that 

 they are capable of being greatly increased by selection. This feature 

 is being carefully considered in all corn-breeding work. 



There is a great demand throughout the Southern States for races 

 of cotton with a longer and finer staple than is found in the ordinary 

 upland sorts. This demand, it is believed, can be filled by produc- 

 tion of forms combining the ordinary upland with the long staple sea 

 island. A number of such hj^brids were made last year and are being 

 grown this j^ear for testing and selection. Some work of this nature 

 carried on by private growers has already yielded results of value, 

 and the investigations as a whole give great promise. 



The i3ineapple hybrids mentioned last yenv, of which about 600 have 

 been produced, are being grown and tested in Florida. Many of them 

 will fruit next year, and their true value can then be determined. 



The successful results obtained in securing hardy varieties of grapes 

 adapted to California and the Pacific coast generally was pointed out 

 last year. This j^ear's work, however, emphasizes the importance of 

 these results. The work was started several j^ears ago, mainly to find 

 means of overcoming certain inherent weaknesses in the vine which 

 led to the loss of the fruit soon after the blosson?s set. The new forms 

 show none of this weakness, and have yielded fruit of much promise. 



During the year the work on the improvement of pears and other 

 pomaceous fruits was continued. A number of valuable crosses have 

 been secured between the Oriental or sand pears and some of the 

 more delicate kinds, like Bartlett, Seckel, etc. The Oriental pears 

 are verv hardv and resistant to disease, and the crosses were made 

 with a view of obtaining more vigorous kinds than we have at i^resent. 



PLANT NUTRITION. 



In my last report special attention was called to the Avork on j^lant 

 nutrition in relation to the health of plants and their productiveness. 

 The principal elements constituting the mineral nutrients of plants 

 have long been known, and the question of the availability of the xnvi- 

 ous elements in the numerous fertilizers used and in soils has been 

 and is still being carefully studied for different crops. The experi- 

 ment stations are doing valuable work along this line. Another and 

 a very important phase of the work, which has hitherto received com- 

 paratively little attention, is the study of the function of each of the 

 mineral nutrients in the nutrition of the plant. This subject received 

 special attention during the year, and a bulletin entitled "The phys- 

 iological role of mineral nutrients" was prepared and published. The 

 bulletin brings together all that is known on the subject up to the 

 present time, and embodies much original work also. It was designed 

 especially for experiment-station workers. In the investigations 

 special attention was given to calcium and magnesium. Contrary to 

 former belief, the association of the two compounds in proper relation 

 has been found to be one of the most important requirements for the 

 vigorous and healthy growth of plants. 



TOBACCO INVESTIGATIONS. 

 CURING AND FERMENTATION. 



The cooperative work with the Division of Soils on tobacco investi- 

 gations started two years ago has been continued. It has been found 



