مرکز منطقه ای اطلاع رساني علوم و فناوري - تاثير سرما و گرماي گسيخته و پيوسته بر سرعت شكفتن جوانه هاي مو رقم سلطانين

چكيده لاتين :

Several experiments were conducted in Khalatpoushan Station of the University of Tabriz using completely randomized design with three treatments and three replications in order to identify the effects of interrupted and continuous chilling and heating on budbreak rate in ʹSultanaʹ grapevines in 2001. The grapevine shoots were removed on the 18th of Oct. in 2001 and 28th of Jan. in 2002. In control treatment. to save the chilling requirements of buds. cuttings were exposed to continuous chilling at 4 °C for 9 days (200 hi.). In order to interrupt continuous chilling in the other two treatments, after completing one- and two-thirds of chilling requirements of buds at 4"C. cuttings were exposed to 20 and 2.5 °C for I. 2 and 7 days and then were exposed to 4 °C until completion of chilling requirements of the buds. The results indicated that treatment with interrupted chilling at 25 °C for 7 days was better than the continuous chilling treatment at 4 °C for 9 days in breaking dormancy of grapevine buds. Also. continuous chilling at 20 °C for 1 or 2 days after the completion of two-thirds (6 days) of chilling requirements of buds. caused reductions in budbreak percentage and budbreak rate as compared to the control treatment (9 days continuous chilling). Therefore- interrupted chilling treatment at 20 "C for I or 2 days following the completion of one-third (3 days) of chilling requirement of buds was similar to the continuous chilling treatment for budbreak percentage and rate. Also, the results indicated that the effect of high temperature during the chilling period on budbreak rate of grapevines buds depends on the dormancy stage of the buds. Therefore. cuttings on 28 th of Jan. 2002, on which buds were finished their dormancy period. high temperature (20 °C) for 1 day during the chilling period of 9 days did not affect budbreak rate. In another experiment. to study the effect of low temperature on the heating requirement of buds for budbreak, cuttings were obtained on 12 th of Feb. 2002. Analysis of data showed that interrupted heating at 4°C did not affect the amount of heat requirement for the days to .50% budbreak as compared to continuous heating treatment. It can be concluded that accumulated heat for budbreak is accumulative.