Cultivo in vitro e crioarmazenagem de sementes de mamona (Ricinus communis L.).

Abstract

The castor (Ricinus communis L.) has great importance for the economy of the half-barren northeastern that is responsible for 80% of the national production, but between the decade of 70 and the year 2000, the liquid production of this oleaginous was reduced at 80%. The existence of about 90 different types of seeds used in the culture of this Euphorbiaceous was also registered. According to this problem the objective of this was work to develop a technique of cryoconservation and micropropagation aiming during to keep the genetic stability of two varieties of Ricunus communis or at least reducing the risk of instability during the time. In all the research the used experimental delineation was entirely casually, being that in the sterilized of the seeds the data was taken at the 14th day of the inculcator, with a factorial array of 2 x 2 x 2 x 2 (2 varieties x 2 methods of dormancy in addition x 2 active chlorine concentrations x 2 periods of decontamination) with ten replications containing three seeds for bottle; in the induction callus the data had been taken in 28° day of the inoculation of the explants, with factorial array 2 x 12 (2 varieties x 12 concentrations of regulators of growth) with ten replications containing three explants for each bottle and in the crioconservation the data was taken at the 7th and 14 day after the sowing, with a factorial array of 2 x 3 x 2 x 2 (2 varieties x 3 periods of crioconservation x 2 temperatures of crioconservacion x 2 types of preservation) with eight replications of twenty and five seeds each. The obtained data were submitted to analysis of variance and their averages of the qualitative factors compared by the test of Tukey, 5% of probability. With the obtain results it can be concluded that: the critical level of moisture for the crioconservation of the seeds of the two varieties of Ricinus communis (northeastern and pernambucana) was between 4 and 10% wet base; the seeds of the studied varieties of Ricinus communis had a better performance in its physiological quality at its thirty days of crioconservation and can either be cryostoraged in the vapor (-176 °C) or by immersion (-196 °C) in liquid nitrogen; canister of aluminum to condition the seeds revealed to be betterthan the one of PVC; the best methodology for the decontamination of seeds of the two studied varieties of Ricinus communis. Is the one that uses seeds without sterilized tegument in a solution with 2,0% of active chlorine during 10 minutes; the best production of friables calluses was obtained by with explained of hypocotyls with half composition of 1,0 mg.1-1 of ANA and 2,0 mg.1-1 of 2iP (MS10) for the variety northeastern and the half composition of 1,0 mg.1-1 of ANA and 2,0 mg.1-1 of BAP (MS6) for the pernambucana variety.