Kenneth Gravois and Keith Bischoff

New sugarcane varieties are the lifeblood of the Louisiana sugar industry. In fact, the high and the low points of the Louisiana sugar industry closely parallel those of sugarcane variety development. The first sugarcane varieties grown in Louisiana were of foreign origin. Introduced varieties were typically renamed and included “Creole,” from which Etienne De Bore first granulated sugar, “Otaheite,” and later “Louisiana Striped” and “Louisiana Purple.”

Later, sugarcane varieties were improved by producing sugarcane seedlings through crossing. Crossing involves taking pollen from one variety to fertilize seeds of another variety to create a new plant with desired characteristics from both parents. The fertility of the sugarcane flower was first established in 1858 at the Highlands Plantation in Barbados. Not until 1889 in Barbados (and soon thereafter in Java) were the first seedlings successfully produced through crossing. In 1890, seedcane from these first seedlings developed in Barbados were grown in Louisiana at a research facility inAudubon Park in New Orleans. The term seedcane refers to the fact that sugarcane is planted as stalks rather than seed.

In the 1920s, sugarcane diseases decimated the Louisiana sugar industry. The only way to overcome the disease problem was to introduce new varieties. Through the U.S. Department of Agriculture (USDA), new foreign sugarcane varieties, primarily the POJ varieties from Java, and seedlings were imported and quarantined. In 1922, the Louisiana Agricultural Experiment Station (LAES) received seed from the USDA Sugarcane Station at Canal Point, Fla. After the USDA established a Sugarcane Research Unit at Houma, La., seed from Canal Point were sent there. Evaluation of varieties from both foreign introductions and seedling sources was initiated in 1924, through the cooperative efforts of the LAES, the USDA and the American Sugar Cane League.

Developing New Varieties

New sugarcane varieties begin with the creation of new genetic combinations through crossing. Because sugarcane is a tropical plant, it rarely flowers under natural conditions in Louisiana. From 1950 to 1953, LAES scientists attempted to cross sugarcane at one of Louisiana’s southernmost points, Grand Isle. After discovering that sugarcane flowers according to a photoperiod (day length) response, sugarcane crossing was begun in Baton Rouge in 1954, with the aid of photoperiod induction facilities on the LSU campus. In 1982, photoperiod, crossing and seedling facilities were constructed at the LSU AgCenter’s St. Gabriel Research Station, where sugarcane breeding continues today. The American Sugar Cane League was helpful in establishing these new facilities. The AgCenter’s sugarcane breeding program is the only one in the world that relies solely on controlled photoperiod induction to produce flowers for crossing.

The development of a new sugarcane variety takes many years (Table 1). Crossing in the LSU AgCenter breeding program is done each fall. Seed produced in the crossing program is germinated the following January in the greenhouse. Seedlings are potted into individual cells in a tray system in February. In mid-April, the seedlings are transplanted into the field with 16-inch spacing. The plantcane seedling crop is harvested, and selection is practiced the following year in the first stubble seedling crop.

First stubble refers to the first crop of stalks that develops from buds on the stubble remaining in the field after harvest. Stalks of selections from the single-stool seedling stage are planted in First Line Trials (single-row, 6-foot plots). The following year, selections from the First Line Trials are advanced to the Second Line Trials (single-row, 16-foot plots). Experimental varieties selected in the first stubble crop of the Second Line Trials are assigned permanent variety designations.

Variety assignments are planted at three on-station locations (St. Gabriel, the LSU AgCenter’s Iberia Research Station and the USDA’s Ardoyne Farm) as Nursery Trials. The following year the variety assignments are replanted at five off-station locations on cooperating farms as either an Infield Trial or a Nursery Trial. The next year, thesevarieties are introduced as seedcane increases to the Outfield Testing locations and Primary Seed Increase Stations. Outfield Testing is conducted cooperatively by the LSU AgCenter, the USDA’s Sugarcane Research Unit at Houma and the American Sugar Cane League. After the initial seedcane increase at each Outfield location, varieties are planted in a replicated variety trial.

As long as the variety results remain promising, the variety stays in the program and is replanted in the Outfield Testing program. After data are collected on at least one second stubble crop of Outfield Testing, a new variety may be released to the industry. Release occurs 13 years after the initial cross. Seedcane increase for a potential variety release to farmers is done on Primary and Secondary Seed Increase Stations and is the sole responsibility of the American Sugar Cane League. The year after a new variety is released, certified seedcane is available from a commercial seedcane company.

LCP 85-384 Variety

A hallmark of the LSU AgCenter’s sugarcane breeding program was the selection of LCP 85-384 and its release in 1993. The LCP 85-384 story began in the mid-1960s with the establishment of the basic breeding program at the USDA’s Houma unit. The objective of the basic breeding program is to introduce new genes from different species that contribute to disease resistance, stubbling ability and cold tolerance along with higher yield potential.

The prefix “LCP” indicates the origins of the variety. The cross of LCP 85-384 was made at Canal Point, Fla., thus “CP.” The variety was selected by personnel from the AgCenter’s Louisiana “L” sugarcane breeding program. The parents of LCP 85-384 are CP 77-310 and CP 77-407. The male parent, CP 77-407, was developed in the USDA basic breeding program, which has as its objective to broaden the genetic base of new sugarcane varieties.

LCP 85-384 has provided a 20 percent to 25 percent yield increase over varieties grown at the time of its release. In addition to its unsurpassed yield potential, the variety offers excellent stubbling ability and cold tolerance. These characteristics make it possible to grow more crops from a single planting.

Because of Louisiana’s temperate climate, the sugarcane crop must overwinter for two to three months. Before LCP 85-384, the typical rotation for sugarcane grown in Louisiana was a plantcane crop and two stubble crops. In years with mild winters, some third stubble crops could be grown. The typical rotation with LCP 85-384 is a plantcane crop plus three to four stubble crops. With depressed prices for sugar, the increased production from LCP 85-384 and the additional crops grown from the initial planting have kept Louisiana farmers in business.

Harvesting

Harvesting in Louisiana has been done with whole stalk harvesters since the 1940s. The sugarcane breeding program emphasized harvesting characteristics such as erectness and non-brittleness in the selection and release of new varieties. The varieties CP 52-68 and CP 65-357 were developed for adaptability to whole stalk harvesting systems.

LCP 85-384, on the other hand, helped usher in the age of combine harvesting in Louisiana. Because of the variety’s high tonnage and lodging characteristics, harvesting LCP 85-384 with whole stalk harvesters is difficult. The combine harvesting system works more efficiently and has helped farmers realize the potential of LCP 85-384.

The economic impact of LCP 85-384 has been tremendous. In 2001, it was grown on 82 percent of Louisiana’s sugarcane acreage. The higher yields and larger number of stubble crops have helped both the farm and the sugar factory. Increased production has helped increase profits on all farming operations. Sugar factories have realized full capacity after many years of being underused. The annual impact of LCP 85-384 has been to infuse at least $100 million into the Louisiana economy through the sugar industry.

Dependency on one variety is risky, however. If LCP 85-384 were to become susceptible to a disease, for example, then a high percentage of Louisiana’s cane could be affected. To prevent this, Louisiana’s sugarcane breeding program has been expanded to facilitate new variety development. Both the LSU AgCenter and the Louisiana sugar industry through the American Sugar Cane League have contributed resources for this expansion.

Another advantage of LCP 85-384 is that it is a good parent as well as producer. The AgCenter’s breeding program is developing new varieties derived from crosses involving LCP 85-384 as a parent. The goal is creation of varieties with as high or even higher yield potential along with disease and insect resistance.

New sugarcane varieties have paid and will continue to pay big dividends for Louisiana sugarcane farmers and processors.

Crossing House Photos

(This article appeared in the fall 2001 issue of Louisiana Agriculture.)