52 BULLETIN 815, U. S. DEPARTMENT OF AGRICULTURE. 



Table VI presents the average annual yield of the lemon trees of 

 the various strains of the Lisbon variety in the investigational plat, 

 sho\\dHg their total crops and the yields of Green, Tree-Ripe, and Cull 

 fruits. Figure 4 shows these data graphically, and the percentage of 

 fruit of each grade is shown in Table VII. The Lisbon strain is seen 

 to be the most productive one. The Bull strain is very nearly as 

 productive and bore a higher proportion of green fruit, but the lower 

 quahty and poor appearance of the fruit of that strain make it much 

 less desirable than that of the Lisbon strain. The low average of 

 the Dense-Unproductive strain and its high percentage of Green-grade 

 fruit is particidarly noticeable. Every tree of this strain produced 

 more fruit of the Cull grade than of the Tree-Ripe grade. The fruit 

 borne by the trees of this strain is of very little value commercially. 

 The trees of aU the strains except the Open strain are characterized 

 by a dense or semidense habit of growth, and the effect of this con- 

 dition is reflected in the percentage of fruit of the CuU grade produced 



^a;^<s^<x<i'iiKt!)ity/nrs7Xitivas.7Swamam^ /Sis:s2mmmmma ■sun AUiat 



Fig. 4. — Diagram showing the average annual total crops and the weight of fruit of the different commer- 

 cial grades produced by the trees of the several strains of the Lisbon lemon occurring in the investiga- 

 tional performance-record plat during the 4-year period from July, 1913, to Jime, 1917, inclusive. The 

 data for the trees of the Bull strain and three other trees, as indicated in Table I, cover only three years. 

 The strains are ranked according to the weight of their average total crops. 



by the trees of the different strains. Table VII shows the trees of 

 the Open strain to have had 11.8 per cent of fruit of the Cull 

 grade, the next highest proportion, 5.16 per cent, being borne by the 

 trees of the Dense-Unproductive strain. 



The last two columns of Table VII show the average number and 

 percentage of variable fruits produced by the trees of the different 

 strains during the performance-record period. While all except the 

 Open strain are shown to bear very large percentages of fruit of 

 variable forms, the greater proportion of them on the trees of the 

 Bull, Lisbon, and Open strains are of the fluctuating type previously 

 described. The fruits of the Dense-Unproductive strain are prac- 

 tically aU of forms characteristic of that strain, and the trees of the 

 Sporting strain produce a relatively large percentage of fruit which 

 differs very markedly from the typical fruit of the variety. Figure 

 5 shows graphically the variations between the different strains in the 

 percentage of variable fruit produced. 



