New Kinds of Sugarcane

by GEORGE B. SARTORIS

PROGRESS in improving sugarcane has been in the direction of increasing yields and developing varieties that can be harvested more easily and economically by machines. Higher yields were obtained by producing disease-resistant varieties especially adapted to the various regions where sugarcane is grown in the United States. The primary objectives in developing machine-type sugarcanes are to lower the cost of production and to eliminate back-breaking tasks, without losing the precision and quality of hand harvesting.

For a long time new varieties have been needed. Most of the varieties grown commercially used to be soft, large-stemmed noble varieties belonging to Saccharum officinarum, although several harder and slender-stalked varieties of S. sinense and S. barberi were also used. Only a few of these natural varieties (although each was known by several different names) attained commercial prominence. With modern methods of breeding, many new varieties were produced by hybridization. Most of the first breeding was with the noble varieties, but it was soon learned that they could not bequeath disease resistance and increased yields. Breeders then turned to crossing varieties of S. officinarum with varieties of the widely distributed wild cane, S. spontaneum, and with the Temperate Zone varieties of S. barberi of India. Species crosses have produced the high-yielding, disease-resistant varieties now grown almost universally.

The crossing of natural varieties from the Temperate Zone (Chunnee) and Saccharum spontaneum of India with tropical varieties has enabled the breeder to produce varieties especially adapted to the temperate climate of the United States. These new trispecies hybrids have replaced the tropical noble canes. Here we shall not be interested in all the C. P.—that is, Canal Point, Fla.—varieties, but only in those that have been

This genealogical diagram shows the lines of descent of the Canal Point, Fla., sugar. cane varieties now grown commercially in the United States. The boxes across the top show the original varieties and species. There are two varieties of S. spontaneum, one of S. barberi (Chunnee), and eight noble cane varieties (S. officinarum). The commercial C. P. varieties are shown in the bottom row of boxes. Note that all are trispecies hybrids, since each has some noble blood, some Chunnee blood, and some wild blood. The varieties given in the box with C. P. 29/ 103 and all those to the right have wild blood from two sources, India and Java.

released for general culture since 1941, and with two somewhat older varieties that are especially adapted to the new methods of harvesting.

Most of the new C. P. varieties are resistant to red rot, root rot, and mosaic. All are susceptible to chlorotic streak, but this disease is controlled by hot-water treatment of seed cane or by rogueing.

C. P. 29/320 and C. P. 29/120 already are old-timers, although both varieties are still in their teens. They merit consideration because they possess the essential characteristics that adapt them to machine harvesting. C. P. 29/320 is the dominant variety in the northern section of the Louisiana Cane Belt, and also is grown extensively in the Bayou section of southern Louisiana. Although it may continue to be a prominent commercial cane, its importance is historical; it was the guinea pig for the harvesting machines. Much of the early experimental work with cane harvesters was done in fields of C. P. 29/320.

C. P. 29/120 was almost a failure. It lacks eye appeal. The trash clings to the relatively short stalk. Its straight stalks of uniform height, however, are admirably adapted to machine harvesting, and with the development of practical harvesters its merits were soon recognized. Here was a variety tailored to the machine. During the war years the acreage of C. P. 29/120 was expanded rapidly.