Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 31, 1998
Publication Date: N/A
Interpretive Summary: Plant mutants are forms that deviate from the normal. While most mutations are undesirable, as evidenced by the connotation of the word, they are key to identifying genes and understanding gene function and location. For many crops, mutant forms are studied, published, maintained in collections, and distributed to researchers. No sugarcane mutants have been registered, and this deficiency has complicated studies of its genetic makeup. A severely stunted plant, that we called Dwarf1, was discovered in tissue culture plants of LCP 83-137. In this study we measured the growth and development of Dwarf1. We found that Dwarf1 produced an extremely shortened stalk compared to LCP 83-137, and that the reduction in stalk length was due to shortened internode length. Leaf architecture of Dwarf1 was noticeably different from that of LCP 83-137, and resembled the dwarf mutants of maize. The dwarf trait was stable. Dwarf1 flowered and produced seed allowing us to study the sexual transmission of the trait. We found that the dwarf trait was rather strongly transmitted to the offspring, and that offspring had either dwarf or normal stature. This type of transmission is very rare in sugarcane. Through this registration we document the discovery of this rare, stable sugarcane mutation, and make the plant available for distribution to other researchers for genetic, breeding, and physiological studies.
Technical Abstract: Sugarcane (Saccharum L. interspecific hybrid) is a polyploid whose genetics are complex and poorly understood. No known sugarcane mutants have been registered, further complicating its genetic analysis. A mutant genotype, called Dwarf1, was identified in 1990 among 216 callus-derived plants of LCP 83-137. Dwarf1 had stunted growth and abnormal leaf architecture resembling maize dwarf mutants. At 12 mo, stalks were 0.7 and 1.9 m long for Dwarf1 and LCP 83-137, respectively. The dwarf stature was caused by shortened internode length, not reduced number of internodes. Compared to LCP 83-137, Dwarf1 had thicker stalks, and 14 to 29% lower sucrose concentration. Chromosome loss may have contributed to the trait. Repeated application of gibberellin-3 failed to stimulate internode elongation, suggesting that the mutation affected gibberellin reception. Dwarf1 was susceptible to infection by leaf scald [caused by Xanthomonas albilineans (Ashby) Dowson]. Segregation analysis of 10 crosses (271 progeny) with Dwarf1 showed that the trait was qualitatively transmitted in a ratio of about 1 dwarf : 2 normal progeny. Dwarf1 was vegetatively propagated with no reversion to normal phenotype. This genetic stock should be useful as a marker in breeding and genetic studies. It may also have aesthetic value as an ornamental.