LONG Wen-hong1，XIAO Guan-li2，WANG Qiong3，SHA Ben-cai2，GUO Hua-chun3*
. 2011, 1(12): 56-59.
In order to study the effect of paclobutrazol（PP333）and chlormequat（CCC）on dormancy-break of yam（Dioscorea batatas Decne.）bulbils，yam bulbils were treated with different concentrations （0.1 mg?L-1，1 mg?L-1，10 mg?L-1，100 mg?L-1 and 1 000 mg?L-1）of PP333 and CCC solutions when bulbils were just harvested，stored for 60 days and for 90 days，respectively．Two treatments were used in this study．The first one was that bulbils were cultured in PP333 and CCC solutions until germinating．The second one was that bulbils were soaked in solutions for 24 hours and cultured in sand．The results showed that PP333 solutions （0.1-1 000 mg?L-1）could not break the dormancy of new bulbils．41.3 %-61.8 % bulbils which had been stored for 60 days germinated after being cultured in 0.1-100 mg?L-1 PP333 solution for 30 days，while 92.5 % and 97.5 % bulbils germinated when they were cultured for 45 days in 1 mg?L-1and 10 mg?L-1 PP333 solution，respectively．Those germination percentages were all significantly higher than the control．The germination percentages of bulbils soaked in 10 mg?L-1 and 100 mg?L-1 PP333 solution for 24 hours then cultured in sand after being stored for 60 days were significantly higher than the control．The bulbils which were soaked in 0.1-1 000 mg?L-1 CCC solution for 24 hours and cultured in sand failed to germinate．While the bulbils which were cultured in 0.1 mg?L-1 CCC solution after being stored for 90 days could germinate，and the germinate percentage（60.0 %）was significantly higher than the control．All these results indicated that the dormancy of bulbils been stored for 60 days could be broken by aquiculture in 1-10 mg?L-1 PP333 solutions，and PP333 was more effective than CCC．
