Sugar Lines from Available Varieties

During the 90 years since the first group of 17 varieties were introduced from China and Africa, an immense number of variant forms were evolved by selection or by planned hybridization and by new introductions. Moreover, much confusion of names was injected in the first years by promoters who took advantage of the widespread interest in the new crop by rechristening varieties so as to enjoy temporary advantage by selling seed of "new and improved" varieties. The result was that the same variety was known by many names and they, superimposed on many legitimate new names, resulted in a formidable list. The process of coining new names, both legitimate and illegitimate, was carried on to the point where it was difficult to untangle the confused nomenclature and assay the existing material in a methodical way. No less than 389 "domestic varieties," or at least plant materials with that many designations, have been assembled at the Meridian, Miss., station.

Because of the systematic studies of competent agronomists, including C. R. Ball, and the late H. Vinall, C. V. Piper, and H. B. Cowgill, many of the more or less true-to-seed sorts in that assemblage are recognizable, but it requires a specialist to determine varieties with any degree of certainty. Every year since 1941 thousands of chemical analyses and studies of various kinds, genetic, pathological, and agronomic, have been conducted on the mass of plant material in an effort to sift out the best "sugar lines" and "sirup lines" suitable as beginning points for breeding and to continue breeding and selection with combinations already made.

Fourteen crosses of domestic varieties considered promising as sugar lines have been made. They comprise various combinations of Honey, Collier, Rex, Hodo, and White African with Cowper, Sourless, Straight-neck, Hodo, S. A. 287, and Early Folger 9097. Sirup lines are represented by crosses of Hodo, S. A. 287, White African, Coleman (M), S. A. 108, and Iceberg in various combinations with C. P. Special, Early Folger 16154, Cowper, and Straightneck. All of them have now been carried to the F6 generation. The best results have been obtained from Hodo X Early Folger 9097. More recently, exploratory crosses were made to find parents that would transmit high yield and disease resistance; they represented 43 combinations of Rox Orange, S. A. 183, M. N. 60, M. N. 61, Texas Blackhull Kafir, Sugary Feterita, Dawn, Blackhull Kafir, Georgia Blue Ribbon, Straightneck, Iceberg, M. N. 51, and M. N. 352 with S. A. 287 C, Sumac, Coleman Y, McLean, Silvertop, Saccaline, Leoti, S. A. 107, Rex, Honey, Hodo, Atlas, and Early Folger 16154.

The results indicate that the only good domestic parent varieties for intercrossing are Collier, Rex, Honey, Early Folger 9097, White African, and Hodo. Combinations of these are not likely to produce high-yielding varieties for sugar production, but because Hodo is rank-growing there is a good possibility of increasing sirup yields.

Rex, Collier, and Honey were used in 1944 for more than 200 crosses with a number of the large, robust varieties obtained from Ethiopia and India. Promising parents among the latter include M. N. 414, 423, 531, 534, 543, and 684. The F2 generation was grown in 1946. Although its progenies will be actively segregated, it is probable that there will be enough material to permit selection of parents that may produce the type wanted. As indicated before, this line of breeding—crossing of the promising large tropical varieties with domestic varieties—is the main hope for success. At this stage it is only well begun.