182 ANNUAL KEPORTS OF DEPARTMENT OF AGRICULTURE. 



seedless puniinelo from Sijiiii proved disai)pointing, the fruit proving 

 to bo very seedy when grown in a mixed phuiting. Kecent investi- 

 gations in Siam indicate that seed i)ro(hi('tion is dependent on the 

 ilowers becoming pollinated by seedy varieties of citrus. Authentic 

 bud wood of the best Siamese varieties has been secured to permit a 

 further test of these pummelos in America. 



Eustis Umequat. — Among the numerous citrus hybrids developed 

 in the breeding investigations is one originating as the result of a 

 cross between the common lime and the kumquat which gives promise 

 of achieving considerable economic importance. The fruit resulting 

 from this cross, called the limoquat, has the acid flavor of the lime 

 and yet possesses much of the hardiness of the kumquat. The lime, 

 as is Avell known, is so tender that its culture is chiefly limited to the 

 coast keys of Florida, so that a hardy lime, such as the limequat 

 promises to be, will fill a much felt want in the citrus-growing section 

 of the (jrulf coast. The limequat is handsome in appearance, \ igor- 

 ous in growth, and of everbearing habit, produ.cing fruit for a con- 

 siderable portion of the year. A selected hybrid of this class has 

 been named the " Eustis," the original cross-pollination having been 

 made at Eustis, Fla. It is being propagated commercially and should 

 find a place in home fruit gardens in Florida and throughout the 

 Gulf coast region, and possibly for more extended commercial grow- 

 ing when fully tested. 



TOBACCO. 



Work with tobacco in the Connecticut Valley during the year has 

 beeji limited to a careful study of "tobacco-sick" soils. Th.ore are 

 numerous fields which have previously yielded satisfactory crops of 

 tobacco but have now become unproductive. It is found that the well- 

 Iviiown Thielavia root-rot is only partly responsible for the trouble, 

 and apparently a second parasitic organism is involved. In the Burley 

 district of Kentuclry the resistant strains of the older type of White 

 Burley have given satisfactory results in the presence of the Thielavia 

 root-rot, and some of the farmers are growing these strains on dis- 

 eased land. Work has been continued in develr)ping disease-resistant 

 strains of the newer " stand-up " type of Burley, for which there 

 is an increasing demand in the smoking-tobacco industry. In Wis- 

 consin a strain of cigar-binder tobacco highly resistant to root-rot 

 which has been recently developed is becoming quite popular with 

 growers, and it has been estimated that 2,500 acres of this strain will 

 be grown this season. 



Field experiments have been continued with a view to working out 

 the fertilizer requirements of the principal types of tobacco, and some 

 of these tests are about completed. The results of extensive tests 

 with flue-cured tobacco in Virginia, North Carolina, and South 

 Carolina extending over a period of 10 3^ears are now being prepared 

 for publication. These tests will furnish information as to the most 

 profitable forms and rate of application of nitrogen, phosphoric acid, 

 and potash and as to the value of liming the soil for the tobacco 

 crop. Beginning this year, these investigations have been changed 

 in scope so as to cover a comprehensive field study of crop rotation in 

 connection with the more imi)ortant fertilizer problems. Fertilizer 

 tests similar to those in the flue-cured districts have been continued in 

 Maryland, Tennessee, and the Onondaga district of New York, and 



