UNITED STATES DEPARTMENT OF AGRICULTURE 
Contribution from the Bureau of Plant Industry 
WM. A. TAYLOR, Chief 
Washington, D. C. PROFESSIONAL PAPER June 1, 1920 
CITRUS-FRUIT IMPROVEMENT: A STUDY OF BUD 
VARIATION IN THE LISBON LEMON:: 
By A. D. SHameEt, Physiologist, L. B. Scorr, Pomologist, C. 8S. PomEroy, Assistant 
Pomologist, and C. L. DyErR, Scientific Assistant, Fruit-Improvement Investigations, 
Office of Horticultural and Pomological Investigations. 
CONTENTS. 
— - Pacesa | Page. 
Importance of the lemon industry........... 1 | Lessons taught by these investigations...... 11 
History of the Lisbon lemon variety........ Ze eeresenita GlOonmO led ata nae eee eee 12 
Variability within the variety.............. 3._| Comparative value of the strains...........- 62 
Objects of the investigations. ..-...-...... 3 | The unintentional propagation of undesir- 
Riancorthemnvesticatlonse == s- ees a Ava oes aDLeIStraimsy 6 sees al cals way nee gts 63 
Methods of keeping performance records.... - 5 | The isolation of strains through bud selection 64 
Descriptions of the important strains........ 6 | Top-working undesirable lemon trees... -.. 64 
isbon strain ee 6220s s0 28 fen ie see See 6 | Replacing undesirable trees in bearing or 
OWENES Uap Marg whce seen s eee 7 CHaLGS eed aise nce ice ee ee eee 67 
Dense-Unproductive strain.............- 8 | The selection and care of bud wood.......- 68 
BUS (rales ee pssteesee oo Sees ye Se i) | SUMMA TVA We ccc ee dk Ee cesar  creercinre a rcteyatnye 69 
WeraeenieGl Singin 6 Gexnoosodaosccedeaode OM 
SPOLtMe Strabane acres eels ose 10 | 
IMPORTANCE OF THE LEMON INDUSTRY. 
In the United States, the lemon (Citrus limona Osbeck) is grown 
commercially practically only in California. According to the Thir- 
teenth Census of the United States there were 957,000 lemon trees of 
bearing age in the United States in 1910, and 396,000 under 
bearing age, of which 941,293, and 379,676, respectively, were in 
California. The total production of all States in 1909 was reported 
in the Thirteenth Census as amounting to 2,770,313 boxes, of which 
California produced 2,756,221 boxes. 
Additional information concerning the lemon industry of Cal- 
ifornia will be found in United States Department of Agriculture 
Bulletin 813, entitled ‘‘Citrus-Fruit Improvement: A Study of Bud 
Variation in the Eureka Lemon.”’ 
_ 1 This is the fifth in a series of bulletins summarizing the citrus-fruit improvement investigations of the 
Department of Agriculture. The four former reports, U. 8. Dept. Agr. Buls. 623, 624, 697, and 813, 
presented the results of studies with the Washington Navel orange, the Valencia Grane, the Marsh grape- 
fruit, and the Eureka lemon, respectively. 
137435°—°0— Bull. 815——1 
