Thus far three methods have been used in the production of seedlings : First, seed has been har vested in a haphazard way from varieties that it was desired to propagate This method has pro duced a large number of seedlings whose parent age pollen is unknown. Second, an attempt has been made artifically to fertilize certain pani cles by giving them an excess of pollen of a given kind, such as by placing near them, at the proper time, panicles of other plants, either by removing these latter from distant canes or by previously having planted the canes near by. This has re sulted in the production of a considerable number of seedlings, whose parentage pollen is uncertain, but less so than by the first method. Third, by emas culating definite blossoms before the ripening of their pollen, and by supplying fertile pollen of another sort at the proper time. Owing to the diffi culty of accomplishing this the number of such seedlings has thus far been limited to a few hun dred. By far the greater proportion of these have been produced in the West Indies, notably at the experiment station of Harvard University, where it is said that several hundred such crosses have been made.
The third method is the only scientific one, and it is probable that the difficulties will be so much les sened by experience that it will soon be possible to produce crosses of definite parentage with ease. As such can then be repeated at will, a definite knowledge of cane pedigrees can be established. This will lead to accuracy in the breeding of new varieties. It is probable that the rapidity of our progress in this direction will be in proportion to the accuracy of our knowledge of pedigree, as is the case with other species.
With regard to the improvement of present varieties by these methods, there can be no doubt about the great value of the improvements already effected. Reports show that disease-resistant varie ties have been produced, and the analysis of cer tain seedlings in their first, second and succeeding years, indicate that the sucrose content of sugar cane can be increased in much the same way as illustrated in the recent history of the sugar-beet.
Varieties.
There has been no satisfactory study of the varieties of cane, and, in consequence, there is no satisfactory system of classification of the varie ties. The division most usually spoken of by plant ers, and that which may therefore be inferred to be the one they find most useful, is based on the color of the stalk. Three color groups are recognized: (1) the green and yel low group, in which the stalk is more or less uniformly green or yellow; (2) the red group, in which the stalk is more or less uniformly reddish in color ; and (3) the striped group, in which the stalk is more or less distinctly striped. This grouping is wholly, or almost wholly arbitrary, and presents little to rec ommend it from a scientific standpoint. With the multiplication of varieties following on the production of new crosses, it is to be hoped that increased knowledge will result in improvements in nomenclature. It is manifest that the color scheme mentioned above includes in its striped division canes so closely related to each of the other divisions as to require its division into two coordinate parts, each on a par with the uniformly colored divisions. Many
other objections to the above classification might be pointed out. The great objection to the system is that it leads to the assumption that striped canes, for example, have some important property in common, which is far from being necessarily the case.
Culture.
Soil.—Soil that is good for average agricultural purposes is good for cane. It should be naturally well drained, or if not, drainage should be provided. It is usual to provide drainage by means of open ditches, comparatively little cane land being drained by means of tiles. Soils naturally acid are frequently corrected by the application of lime, and often with very profitable results. Exceedingly stony lands are sometimes profitably used.
The plowing should be deep, the deeper the better, so that the depth is limited only by the kind of plow and the nature of the land. The deep est and best plowing is accomplished with steam plows, the depth reached within economic limits being eighteen inches to two feet. Sometimes sub soil tools are alleged to go below two feet, but that is rare. The limitations are often determined by the nature of the subsoil, which in some localities is such that it is inadvisable to turn it up to the surface except in small quantities. In some volcanic soils, for example, the iron compounds in the sub soil are injurious to the growth of cane.
Good surface tillage after plowing pays as well with cane as with any other crop. All the labor saving implements connected with big-scale agri culture are in use in some regions.
Fertilizers.—Stable manure is one of the best fertilizers, but it is seldom to be had in sufficient quantity, and artificial manures are widely used. Where animal traction is in use there is much stable manure plowed or harrowed in. When com bined with irrigation, the application of commer cial manures may be reduced almost to an exact art. Cane-planters establish their own standards of manure value, and make contracts on the basis of their own analyses, less often making use of state fertilizer control. The proportion of the dif ferent elements used in the fertilizers is influenced to a large extent by the peculiar nature of the industry, which consists of extracting from the crop and sending away from the plantation only the sugar, a carbohydrate containing none of the three most valuable elements in manure, namely, nitrogen, phosphorus and potash. The burning of the trash destroys much nitrogenous fertilizer, but the potash and phosphorous compounds remain on the plantation for future use, and if they are not lost through leaching may be utilized over and over in successive crops. It follows that the most com monly purchased ingredient for cane-fertilizer is nitrogen. The soluble artificial fertilizers are ap plied in small quantities to the surface and with more or less frequency, according to the require ments of the crop. The less soluble artificial manures, such as dried blood and fish refuse, are applied slightly below the surface of the soil, where the conditions are favorable for their decomposi tion.