Genetic variability among sugarcane genotypes from the Karst region of China was evaluated using genotype-specific microsatellite (SSR) markers. Eighteen sugarcane genotypes including 13 active cultivars and five elite QT-series clones bred locally were screened for genetic variability with 21 SSR primer pairs. All the primer pairs were highly polymorphic and amplified a total of 167 alleles with an average of eight alleles per primer pair. The average polymorphism information content (PIC) value was 0.86 with a range of 0.68 and 0.92. A UPGMA dendrogram categorized the 18 sugarcane genotypes into three major groups containing three, ten and five genotypes, respectively. No geographical affinity was observed among genotypes within the same group. Eight SSR primer pairs produced cultivar-specific alleles, of which five alleles were unique to the QT-series clones, namely, . The clone-specific SSR alleles will be useful in identifying elite QT-series clones for use in the sugarcane crossing programs in China.

In this paper, we used plant growth regulators, such as gibberellin and ethephon to treat fruit sugarcane Qiantang 5 respectively. The results show that the spraying of gibberellin on the plants with its concentration of 30g/year.667m 2 has positive effects on most agronomic characters, such as growth speed, plant height, valid stalks, brix, sucrose content and yield. The residue of gibberellin is 0.05mg/kg. However, ethephon has no positive effects on agronomic characters except the growth speed.