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- Author or Editor: João Baptista da Silva x
Aiming to improve plant growth of the apple rootstock cultivar Marubakaido (Malus prunifolia) in greenhouse, 1-year-old plants were sprayed once, twice, and three times in a 7-day interval with gibberellic acid (GA3) in the following concentrations: 0, 50, 100, 200, 400, 800 and 1600 mg•L-1. The plant growth was evaluated every 2 weeks during 2 months. The internode length, bud number, and the dry weight of the aerial part were also evaluated at the end of the experiment. It was verified that GA3 sprayed at 800 mg•L-1 by three times consecutively was the best treatment presenting the largest rate of plants growth (912% against 114% of nontreated plants) in relation to their initial height, besides providing larger internode length and dry matter weight of the aerial parts. However, using this regulator did not affect the plant bud number. Plants sprayed once did not present significant response to GA3 for any of the studied variables. These results suggest that the use of GA3 in 1-year-old apple plants reactivates growth, although, the increase in the number of applications associated with higher doses is necessary to improve the efficiency of this product.
This work aimed to evaluate apple rootstock somaclones by characterizing the genetic variability among them. The isoenzymatic systems were used for analyzing variability as follows: FAC (acid phosphatase), PRX (peroxidase), and 6-PGD (6-phosphogluconate dehydrogenase). The migration were performed by applying a potential difference around 10 volt/linear cm. A data matrix was built so that the genotypes were placed in the lines and the bands in the columns. The scores were attributed as follows: band present (1) and band not present (0). By the gel analyses in relation to the presence/absence and band intensity, we observed marked differences among the somaclones and within somaclones as well. In the peroxidase system a higher band polyimorphism was detected with 18 enzymatic patterns. The group analyses for the 73 apple somaclones revealed a large variability through the enzymes (18 peroxidases, 8 FAC, and 6 6-PGD), which were classified into two groups. Group I was represented by M.7 somaclones with seven subgroups with 43% similarity among the clones. Differences among M.9 and M.111 cultivars and two clones referred to as M9b and M925 were fitted within somaclones M.111. The remaining somaclones of cultivar M.9 showed a higher variability bearing 43 subgroups. Clones M929, M930 and M932 presented 100% similarity.