Ademária Aparecida de Souza

Produção de mudas de tangerineira ‘Ponkan’ em sistema hidropônico

The production in hydroponics of grafted seedlings has been used successfully for various crops, due to its precocity and absence of pathogens, mainly from the soil and substrates. This research was therefore carried out with the aim of studying the feasibility of the production of Rangpur-lime rootstock in a hydroponic system, by determining the optimal diameter of the rootstock for grafting onto the tangerine cultivar Ponkan, and by evaluating the production of the grafted seedlings. The experiment was conducted in two stages in a greenhouse in the Hydroponics Sector of the Department of Soil Science at the Federal University of Lavras in Minas Gerais. In the first stage, the growth of Rangpur lime rootstock (Citrus limonia Osbeck) was investigated. In the second stage, the optimal diameter of the rootstock for grafting was evaluated together with the viability of the production of seedlings of the tangerine cultivar Ponkan (Citrus reticulata Blanco) when grafted onto rootstock of the Rangpur lime. Both steps were carried out in a hydroponic system, using a completely randomized experimental design. The treatments of each experiment were times of evaluation (in weeks) consisting of five replications of five seedlings, giving a total of 25 rootstocks per tube. The rootstock of Rangpur lime with a diameter of 7mm, was the most suitable for the propagation of seedlings of the tangerine cultivar Ponkan (Citrus reticulata Blanco), presenting the best vegetative growth of the graft, with a protrusion time of 91 DAE, surpassing the time for the formation of the citrus seedlings obtained from the other diameters (4, 5 and 6mm). The hydroponic system was shown to be a viable technique for propagating citrus seedlings.

Use of densimetric table to improve the quality of commercial castor bean seeds

Castor bean fruits are already used for biodiesel production but obtaining quality seeds is still a challenge. Seed cleaning improves lot quality but little is known about the effects of upgrading castor bean seed lots on a densimetric table. The objective of this study was to evaluate the influence of cleaning castor bean seed lots on a densimetric table on their physical, physiological and sanitary characteristics. Two commercial lots of the AL Guarani 2002 cultivar, separated into five categories according to their classification on a densimetric table (uncleaned and low, low intermediate, high intermediate and high outlets), were evaluated. Tests for the yield, one-thousand seed weight, germination, seedling emergence, electrical conductivity and seed health were performed. The classification of castor bean seeds on a densimetric table significantly improved the physical, physiological and sanitary quality of commercial seed lots. The physiological response of the different classified lots varied according to their initial weight. Castor bean seeds separated on a densimetric table for the upper outlet showed a better physical, physiological and sanitary quality compared to those for the lower outlet.