Colored cotton has naturally pigmented fibers.The mechanism of pigmentation in cotton fiber is not well documented.This experiment was conducted to study the effects of respiratory chain inhibitors,i.e.,rotenone and thiourea,on pigmentation and fiber development in colored cotton.After 1 d post-anthesis,ovaries were harvested and developing ovules were cultured on the liquid medium containing different concentrations of rotenone and thiourea for 30 d.The results demonstrate that both respiratory inhibitors reduced fiber length and ovule development under ovule culture conditions,and the inhibition efficiency of rotenone was much higher than that of thiourea.Rotenone and thiourea also showed significant effects on fiber pigment (color) development in colored cotton.In green cotton fiber,rotenone advanced fiber pigment development by 7 d at 200 μmol/L,while thiourea inhibited fiber pigmentation at all treatment levels (400,600,800,1000,and 2000 μmol/L).Both respiratory inhibitors,however,had no significant effects on pigmentation of brown cotton fibers.The activities of cytochrome c oxidase (COX) and polyphenol oxidase (PPO) decreased significantly with increasing levels of both respiratory inhibitors.It is suggested that both respiratory inhibitors have important roles in deciphering the mechanism of pigmentation and fiber development in colored cotton.
Shu-na YUANWaqas MALIKShui-jin HUANoreen BIBIXue-de WANG
In order to clarify inheritance mechanism of fertility restoration for cytoplasmic male sterility （CMS） in a new Gossypium barbadense restorer line Hai R which was found in the fertility test crossing of G. hirsutum CMS lines with G. barbadense germplasms. 23 fertility segregation populations of F2 and backcross were used to analyze the inheritance of fertility restoring gene（s） of Hai R. The result showed that Hai R had one major dominant gene （RfB） to control the CMS fertility restoration and this fertility restoration gene functioned at the sporophytic level. The sterile cytoplasm background might not only influence the transmission rate of male gamete but also that of female gamete when the restorer gene was recessive. It could be deduced that this fertility restoration gene might come from G. harknessii cotton, Hai R is of value in the application of cotton interspecific hybrid breeding.
ZHANG Xiao-quan WANG Xue-de JIANG Pei-dong ZHU Wei
