RICE RATOONING - IRRI books - International Rice Research Institute

Breeding and testingfor superior ratooning abilityof rice in TexasC. N. Bollich, B. O. Webb, and J. E. ScottUnited States Department of Agriculture, Agricultural Research Service, andTexas Agricultural Experiment Station, Route 7, Box 999, Beaumont, TX 77706.ABSTRACTCommercial ratoon cropping contributes significantly to rice farmers’ income on theGulf coast of Texas and Louisiana. Ratooning ability has been an important breedingobjective. A primary basis for releasing cultivars Belle Patna and Labelle was superiorratooning ability. Research in the United States on ratooning has been relatively limitedin the United States and has focused primarily on cultural practices. In the breedingprogram in Texas, advanced selections are routinely tested for ratooning ability but noearly-generation selection criteria are available. The field plot techniques are reliablebut relatively labor intensive. Ratoon crop yield appears to be independent of main cropyield. Carbohydrate reserves in the culm at maturity generally have a positive but lowrelationship with ratoon crop yield. Average ratoon yields in research plots haveremained relatively constant for 30 yr. Preliminary indications are that, with goodmanagement, newly developed high-yielding semidwarf cultivars like Lemont andGulfmont can produce significantly higher ratoon crop yields on the Gulf coast thancurrent nondwarf cultivars. Superior ratooning ability is receiving increased breedingemphasis in Texas because it offers the potential to significantly reduce the per unitcost of production.Rice ratooning on a commercial scale in the Southern United States was establishedin 1962 with the release of the very-early maturing cultivar Belle Patna. Before therelease of Belle Patna, no U.S. rice cultivars were sufficiently early maturing forreliable ratoon crop production, although some ratooning was practiced on alimited scale. In 1959, only 4,000-8,000 ha of rice were ratoon-cropped in Texas (5).Research on ratoon cropping initiated in Texas in 1956 included studies of theeffect of cutting height, cultivars, and fertilizer rates on ratoon production (2, 4). Atthat time, the development of cultivars with superior ratooning ability became abreeding objective. Belle Patna was released primarily on the basis of its high yieldpotential through the production of a ratoon crop (1). The widespread popularity ofLabelle, the leading cultivar in the U.S. for a number of years, was due to a largeextent to its superior ratoon crop yields (6).Evaluations of the ratooning potential of promising early-maturing selectionsin the breeding program at Beaumont are conducted in replicated field plots. Thesame plots are used to measure main crop yields and ratoon crop yields. Standard