1268 PI,ANT BREEDING 



young leaves contain too great a quantity of fats and albuminoids, which do 

 not decompose to a sufficient degree during the fermentation of the tobacco. 



In leaves picked at the right time, the mineral salts and organic sub- 

 stances are present in favourable proportions. In this condition of the leaf, 

 the ferments in it are active, and it is these ferments which, during suitable 

 fermentation of the tobacco, are capable of effecting transformation of 

 the starch, sugars, cellulose, fats and albuminoids. 



Unfortunately, the study of the lines chosen among the native races 

 could not be continued each year in as thorough a way as was reported in 

 Bulletin No. 9. Thus, in Bulletins Nos. 12 and 18 the different types are 

 judged from the practical point of view only. For some lines of the races 

 " Deli " and " Kedoe ", however, cultivated on two different fields, statistic- 

 al study was carried a little farther as regards the height of the plants, the 

 number and distance apart of the leaves, and also the number of leaves up 

 to I metre height of the stalk. The results of this analysis are, inter alia, 

 the following. 



i) The field with more moistiire and less sun, a less clayey and 

 lighter soil, produced a greater length of stalk together with greater 

 distance apart and size of the leaves, while the other field with less moisture, 

 more sunshine, and a heavy and clayey soil, yielded more closely packed 

 plants with more numerous and smaller leaves. The two races behave 

 identically. 



2) In both races, the lines with the greatest number of leaves up to 

 I m. height are preferable from the quantitative and quahtative point 

 of view. The types with leaves a short distance apart generally possess 

 a larger number of leaves than others in which the spaces are wider, and where 

 there are small spaces the leaves follow each other more regularly on the stalk, 

 and afford better shade, so that when dry the}^ exhibit a more homo- 

 geneous lighter and duller colour. 



3) The seedlings chosen in the first place from the nurseries yield 

 a finer plantation than the second or third choice of seedlings. All other things 

 equal, backward seedlings will never yield in the open field tobacco plants 

 as healthy and with as many leaves as strong seedlings. Seeds with feeble 

 germs do not, even if the nurseries are manured, produce as strong adult 

 plants as non-manured seedlings derived from strong embryos. 



What is called the " Deli " race is a mixture of man}' genotypes. Se- 

 veral of these types have been under cultivation for j^ears in the east of Java ; 

 for instance the " Deli-Palembang ", " Deli Toentoengan ", " Deli Besoeki ", 

 " Deli-Arensburg ", etc. Even the " Deli-Medan ", however, is composed 

 of several types, and the writer regards the " Deli " race as more variable 

 than the " Kedoe " race. Though the difference may not always be easy 

 to detect in the field, it is obvious on comparing the dry tobacco, and if 

 the trouble is taken to mesure the plants it can be demonstrated mathematic- 

 ally. It is by measuring, counting and weighing certain properties of 

 the phenotypes which for several generations represent the dift'erent geno- 

 types, that a pure line may most effectively be distinguished from a popula- 

 tion of types. 



