USDA Yearbook, 1937, pp. 198-199
CROSSING SUGARCANE AND SORGHUM—A FEAT OF INTEREST TO THE SUGAR INDUSTRY

Only a very limited area in the United States is adapted to the growing of sugarcane, which is essentially a tropical plant. The sorghums, some of which are relatively high in sugar content, are adapted to a wider area. The possibility of producing an entirely new plant of economic value, one with more sugar than sorghum and more adaptability than sugarcane, has interested plant breeders for some time. One of the chief advantages of such a plant would be that sugar factories could be kept in operation over a longer period than is possible with the short sugarcane season.

The sugarcane-sorghum hybrid has actually been made, but so far the possibilities have hardly begun to he explored. As in all crosses between genera, a large amount of material should be used if results are to be expected, and this means keeping several scientists working on the project over a considerable period of time.

The first hybrid was produced by a breeder in India who crossed sugarcane with a grain sorghum The grain sorghums, of course are not notable for sugar content, but the success achieved here showed that the cross could be made. It will be noted from the number of flower heads in the picture (fig. 15) that the work in India is apparently being done on a large enough scale to get results. Recently Department of Agriculture scientists, working on a very limited scale, have made not only this cross (fig. 14) but others between sugarcane and a variety of sorgo called honey. The first-generation hybrids of the sugarcane-grain sorghum cross occasionally have great vigor, as indicated in the illustration by the size they have attained in 7 months as compared with the size of the year-old sugarcane parent.

As was to be expected, the cross produces many abnormal types, including albinos, which, of course, do not live past the seedling stage. Many of the progeny, however, resemble sugarcane and have a satisfactory sugar content. Inasmuch as sugarcane is reproduced vegetatively by cutting up the stem and planting the "seed cane," the work is somewhat simplified since the hybrids may be perpetuated with no danger of change.

FIGURE 14.— Sugarcane X sorghum: Center, sugarcane parent, P. O. J. 2725, 12 months old; at either side, hybrids, 7 months old, obtained by crossing P. O. J. 2725 with Sorghum durra.
FIGURE 15.— Preparing to pollinate sugarcane with sorghum heads in British-India. The beads are collected in the evening, trimmed, and preserved for use in pollinating the sugarcane flower early the following morning. (From Ind. Jour. of Agr. and Science.)