In a somewhat similar way, it appears that the infestation by certain fungous pests is determined, to a certain extent, by the nature of the rind of the stalk where the fibrous matter is in excess, and, the presence of epidermal cells assisting, the resistance of the cane to the fungous pests is in a degree proportional to the amount of the fibrous matter so located.
Another matter connected with the structure of the stalk, and one of great practical importance, is its size. By a mathematical law, the larger the stalk the greater strength will be imparted to it by the distribution in its outer layers of a given amount of fibrous matter. Further, the larger it is, in view of the foregoing fact, the more space is available for the storage of sucrose in the interior tissues. Hence, varieties with large stalks are generally viewed with more favor than those with small stalks. Certain varieties of cane produce a comparatively small number of long stalks, while other varieties tend to produce a larger number of shorter stalks. It is evident that these characters adapt the various varieties to various conditions. Short-stalked varieties are better adapted to certain windy locations.
Not only is the location and distribution of the joints important in determining the value of a variety, as above mentioned, but the size, location and germinating power of buds and roots situ ated at the joints are also important factors. This is so for two reasons: First, the growth of the roots is at the expense of the sucrose near by, so that, if a variety has a tendency to root unneces sarily at the base, then the sugar-yield is lessened. Second, it is the nature of the bud that determines the value of the cane for seed purposes. This factor is important in proportion to the frequency of planting. In some localities ratooning is dis pensed with, so that after each crop is harvested the land is at once replanted. In many localities the cane is allowed to ratoon only once or twice and then replanted. Of course, in such localities the question of seed is one of greater importance than in those localities where the cane ratoon for a long series of years, and is not often replanted.
Varieties of cane differ to a remarkable extent in respect to the germinating power of their eyes. In some varieties eyes in any part of the stalk germinate readily ; in others, only those eyes near the top can be relied on to germinate promptly and vigorously, and these latter are by far the more numerous among the best-yielding varieties. Then,
some varieties germinate much better as plant-cane than as ratoon, while other varieties show much less difference in this respect. The germinating power of a variety depends on the vigor of the buds and on the vigor of the root-tissues developed at each node, but this is not the whole of the matter. It happens that there are insects whose special habitat is the buds of the cane-stalk, and resistance to the attacks of these pests constitutes an important part of the value of cane for seed purposes. Buds, other wise good, are rendered worthies; by the attacks of these pests, so that resistance to them may deter mine the value of the cane for seed purposes almost as much as the production of vigorous buds.
The handling of cane is necessarily rough, and prominent buds are often bruised or broken during the handling. From this it follows that canes with low flat buds are to be preferred to those with round and prominent buds. This is especially the case where the cane has to be flumed for long dis tances, as the effect of the water is to soften the buds and they are then more easily rubbed off as they pass along the flume.
To prepare cane for seed purposes, it is cut into sections, each having one or more buds which it is intended shall germinate and start a new stool. While the new plant is establishing itself, it grows at the expense of the sucrose and other matters stored up in the cutting. It is important, there fore, that this store of food shall be preserved for the use of the plantlet. If the cane is brittle, it is likely to shatter when cut for seed ; that is to say, the stroke of the knife causes each piece to split at the end in the manner familiar to everybody in chips of wood produced by the axe. These cracks afford an opportunity for various organisms to enter the cut ting after it is planted, and cause it to decay much more rapidly than it otherwise would. For this reason a cane that is brittle is one that is of less value as seed than one that is not. For this reason, also, the tops of stalks are more valuable than other parts because they are more succulent, and therefore less liable to shatter. To avoid shat tering, or even cutting, it is the custom of some planters to use whole cane for seed.