Assessment Of Cold Tolerance In Different Sugarcane Varieties Using Molecular Markers

In order to evaluate the cold tolerance of different sugarcane varieties under the rain frost condition, the test was carried out in the frost zone-Rong’an county, Guangxi province with35varieties (elites) that coming from domestic and abroad. Genomic DNAs of35sugarcane varieties were marked by using197pairs of EST-SSR primers,67pairs of gSSR primers and100pairs of SRAP primers, and the genetic diversity among the35sugarcane varieties was assessed using36pairs of EST-SSR polymorphic primers,17pairs of gSSR and72pairs of SRAP polymorphic primers screened out from the above primers. The main results are as follows:1.The correlation analysis showed that:the traits under rain frost were only correlated with the emergence rate, Stem diameter, Millable canes. There was significant positive correlation between percent of green leaves&tratits of stem. The percentage of+1～+5green leaves were significant negative correlation with tratits of stem. Further analysis showed that the evaluation for cold tolerance of sugarcane under the rain frost condition would be more simple and reliable with traits of the percentage of+1～+5green leaves and damage rate of top stem internode according to analysis.2.Clustering analysis showed that:the probability that the variety with good cold tolerance parents would have good cold tolerance will be higher than40%, and the probability that the variety without good cold tolerance parents would have poor cold tolerance will be higher than70%.3.87gSSR bands were obtained, with a mean of5.1bands per primer. The PIC value ranged from0.53to0.93with a mean value of0.84. The DP value ranged from0.54to0.96with a mean value of0.87. And162EST-SSR bands were obtained, on average4.5bands were amplified by each primer. The PIC value ranged from0.43to0.93with an average of0.81. The DP value ranged from0.44to0.96with an average of0.81. And1241bands were obtained, on average17.24bands were amplified by each primer, and89.36%of them were polymorphic. 4. The gSSR genetic similarity coefficients of the sugarcane cultivars ranged from0.4138to0.8046, with the average of0.6251.And the EST-SSR genetic similarity coefficients of the sugarcane cultivars ranged from0.5145to0.7971, with the average of0.6651. And the SRAP genetic similarity coefficients of the sugarcane cultivars ranged0.5773～0.7264, with the average of0.6340. The results show that effect of gSSR was better than that of EST-SSR.5.According to the results of gSSR clustering analysis, the35sugarcane varieties could be classified into7groups, and it could be classified into5groups for SRAP clustering analysis, but it could not reflect the characteristic of zone of the tested sugarcane varieties. Some of the good cold tolerance varieties did not go to the same group, which indicate that the good cold tolerance varieties could not be classified well by clustering analysis, but a few cold sensitive varieties could be classified into the same sub-group. It is concluded that the SSRs markers and SRAP marker were good for clustering the cold sensitive sugarcane varieties, which could be referred for research on cold resistance in sugarcane.