Ubirajara Russi Nunes

Selection of sweet potato clones for the region Alto Vale do Jequitinhonha

An experiment was carried out from December 2005 to July 2006, in the Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), in Diamantina, Minas Gerais State, Brazil, aiming at selecting sweet potato clones for the Alto Vale do Jequitinhonha. We evaluated nine clones from the UFVJM germplasm bank, using cultivars Brazlândia Branca, Brazlândia Roxa, and Princesa as controls. The experimental design was blocks at random, with four replications. Plants were harvested seven months after transplanting. We assessed the fresh mass yield of vines and roots, as well as root shape and resistance to soil insects. Genotypes did not differ from each other for the fresh mass yield of vines (ranging from 3.81 to 11.76 t ha-1). The total yield of roots ranged from 22.0 to 45.4 t ha-1 and clones BD-06, BD-113-TO, BD-15, BD-38, BD-25, BD-61, and cultivar Princesa had statistically the highest figures. However, only clone BD-06 significantly overcame the control cultivars Brazlândia Branca and Brazlândia Roxa. Clone BD-06 had also the highest commercial yield of roots (38.58 t ha-1), statically similar to most of the other clones and cultivar Princesa (25.87 t ha-1), but superior to cultivars Brazlândia Branca and Brazlândia Roxa. Most of the clones tested, including clone BD-06, produced good shaped roots and were resistant to soil insects. Considering our results, clone BD-06 stood out as a good option for growing sweet potato in the Upper Valley of Jequitinhonha.

Época, local de colheita e armazenamento na qualidade fisiológica da semente de sempre-viva (Syngonanthus elegans (Bong.) Ruhland - Eriocaulaceae)

The objective of this study was to evaluate the physiological quality of star-flower (Syngonanthus elegans (Bong.) Ruhland) seeds produced at different locations, harvested at different times and then stored under different conditions and for different periods of time. Capitula of S. elegans were colected in two areas of star-flowers plants natural occurrence on the Campus II of the Federal University of the Valleys of Jequitinhonha and Mucuri, in Diamantina, state of Minas Gerais, Brazil, in a typical Orthic Quartzarenicenic Neossoil (location 1) and a typical Hydromorphic Quartzarenic Neossoil (location 2) at 07/04/05, 07/19/05, 08/22/05, 09/21/05, and 10/20/05) and later submitted to germination and vigor tests (Experiment 1). The capitula taken on 07/04/05 (locations 1 and 2) were placed in transparent polyethylene bags and stored either in a seed laboratory at room temperature (20±2oC) or in a refrigerator (5±2oC), for zero, four, eight, and 12 months. After these periods, the seeds were evaluated again for germination and vigor (Experiment 2). A completely random design in a 2x5 factorial was used (harvest time and production location) for Experiment 1; and a 4x2x2 factorial scheme (storage time x location x storage temperature) for Experiment 2, with four replications. The physiological quality of S. elegans seeds varied in function of time and location of production. During storage, germination and vigor did not vary with production location and storage temperature. Storage for 12 months in a refrigerator or at room temperature resulted in higher percentages of normally germinating seeds.

Época de maturação, dispersão, colheita e qualidade fisiológica de sementes de sempre-viva (Syngonanthus elegans (Bong.) Ruhland)

Neste trabalho, objetivou-se avaliar a epoca de maturacao, dispersao, colheita e a qualidade fisiologica de sementes de sempreviva (Syngonanthus elegans (Bong.) Ruhland), em Diamantina, MG. Capitulos de S. elegans foram colhidos em cinco epocas (20/06/ 05, 20/07/05, 20/08/05, 20/09/05 e 20/10/05) em tres locais de producao natural, dentro do Campus da UFVJM em um Neossolo Quartzarenico Ortico Tipico (locais 1 e 2) e Neossolo Quartzarenico Hidromorfico Tipico (local 3) e, posteriormente, submetidos a testes para avaliacao do vigor e germinacao das sementes. A qualidade fisiologica de sementes de S. elegans variou em funcao da epoca e local de colheita. Estrategias de manejo devem ser realizadas como a colheita apos o inicio do periodo de dispersao das sementes (junho a outubro) e com os capitulos totalmente abertos.

Qualidade fisiológica de sementes de feijão em plantio direto sobre diferentes coberturas de plantas em Diamantina, MG

Objetivou-se com este trabalho avaliar o efeito de diferentes coberturas de plantas sobre a qualidade fisiologica de sementes de feijao em plantio direto no municipio de Diamantina - MG. O experimento foi instalado no Campus II da UFVJM, num Neossolo Quartzarenico Ortico tipico, no delineamento em blocos casualizados, com dez tratamentos e quatro repeticoes. Os tratamentos constituiram-se de palhada dessecada e rocada de 1) Brachiaria decumbens cv. Basilisk, 2) Brachiaria brizantha cv. Marandu, 3) Panicum maximum cv. Tanzânia, 4) Panicum maximum cv. Mombaca, 5) Mucuna aterrina (mucuna preta), 6) Calopogonio muconoides cv. Calopogonio, 7) Dolichos lab lab (lab lab), 8) Cajanus cajan (guandu), 9) Cobertura natural e 10) Plantio convencional onde se efetuou o plantio de feijao cultivar Talisma. A qualidade fisiologica das sementes foi avaliada pelos testes de germinacao (primeira contagem e contagem final); condutividade eletrica dos solutos; peso de 100 sementes; comprimento e peso das plântulas; indice de velocidade de germinacao e teor de agua das sementes de feijao. As gramineas Panicum. maximum cv. Mombaca, Brachiaria brizantha cv. Marandu, B. decumbens cv. Basilisk e P. maximum cv. Tanzânia produziram materia seca em quantidade e uniformidade para maior conservacao de agua e protecao do solo para viabilizar o sistema plantio direto. A qualidade das sementes nao foi afetada pelos manejos de solo utilizados e sim pelas condicoes climaticas na maturacao.