Tratamento pré-germinativo de sementes de mandioca e determinação da divergência genética de genótipos provenientes dos clones Aciolina e Gabriela

Abstract

The objective of this paper is to analyze the technical pre- germination treatment of cassava manioc seeds from the clone Gabriela. The analysis was conducted at CCA – UFRR, Boa Vista RR during the period October 2013 to December 2013. Three experiments with a completely randomized layout were carried out, with six treatments (experiments l and ll), seven treatments (experiment lll) and four repetitions for all the other experiments. Experiment l: T1 - Intact seeds; T2- Seeds sanded at the caruncle, T3- Intact seeds immersed in a solution with 2, 5 % of Sodium hypochlorite for 5 minutes. T4 -Seeds sanded at the caruncle and immersed in a solution with 2,5 % of Sodium hypochlorite during five minutes. T5 - Intact seeds immersed in hot water at 80° C until cooled down to room temperature. T6 – Intact seeds immersed in 40% of hydrogen peroxide for 3 seconds. Experiment ll: T1-Whole seeds. T2 - Seeds with the caruncle removed; T3- sanded seeds at the caruncle; T4- Seeds sanded at the opposite side of the caruncle; T5 – Sanded seeds on the opposite side of the caruncle with the caruncle removed and T6 - Seeds sanded at the caruncle and at the side opposite of the caruncle. Experiment lll: T1- Intact seeds; T2 – Seeds with caruncle, scarified at the sides; T3- seeds with the caruncle removed with a pair of pliers. T4- The immersion of Intact seeds in sulfuric acid for ten minutes. T5- Immersion of intact seeds, with the caruncle, in sulfuric acid for 20 minutes. T6 – Immersion of intact seeds in sulfuric acid for 30minutes. T7 – Scarification of the caruncle. The variables analyzed were: The percentages of emergence of normal and abnormal plants from hard and dried up seeds and the indices of the velocity of emergence. The results were submitted to the analysis of variance ((p≤0,05) and the Turkey test at 5% of probability and the measures of the variables were transformed to root ( x+ 0,5). The manioc cassava seeds presented a physical dormance which is overcome with the scarification of the tegument. The manioc seeds after being collected can be sowed as long as they have being through the pre-germination treatment of scarification of the tegument. The scarification treatment of seeds at the sides or at the caruncle, showed more efficiency to increase the emergence over 80%. Key words: Scarification. Bud Breaking. Germination.