Omissāo de macronutrientes no crescimento e no estado nutricional de capim-elefante (cv. Mott) cultivado em solução nutritiva

The objective of this work was to evaluate the effect of omission of macronutrients in the growth and the nutritional state of elephant-grass plants (Pennisetum purpureum Shum cv. Mott). The experiment was developed in the FCAV/UNESP, in Jaboticabal-SP,Brazil, using nutrient solution. The experimental design was completely randomized blocks, with seven treatments (the complete solution proposed by Hoagland & Amon (1950) and the individual omission of N, P, K, Ca, Mg and S, in these solution), in three repetitions. Pre-germinated plants were placed in pot (5 dm3), containing the nutrient solution, which was aerated constantly during the experimental period and the respective treatments, with three replications each. Weekly, the height of the plants, the leaf number, apex diameter and number of tillers were evaluated as well as plant nutritional state. The omission of N, P, K, Ca, Mg and S limited the production of dry weight of shoot the elephant grass, compared to the full treatment. The deficiency of a macronutrient, in addition to promoting reduction of its content in the shoot, resulted in reducing the accumulation of most macronutrients, with resultant morphological changes, translated as characteristic symptoms of deficiency.

Variação, herdabilidade e ganhos genéticos em progênies de Eucalyptus tereticornis aos 25 anos de idade em Batatais-SP

The wood of Eucalyptus tereticornis is intensively used for timber, structures, buildings, poles, posts and coal. The aim of this study was to estimate genetic parameters and genetic and phenotypic correlations in growth and stem form traits of 52 open-pollinated progenies of E. tereticornis sampled from three Australian populations (20 progenies from Helenvale, 19 from Ravenshoe and 13 from Mt. Garnet). The progenies were compared with three commercial control also from Australian. The experimental design used was the compact family block, with the effect of provenance allocated in the plots and progenies within provenances in the subplots. Ten repetitions of the 52 treatments, sub-plots with six plants and the spacing of 3 x 2 m was used. At 25 years of age it was measured the diameter at breast height (DBH), total height, true volume and the stem form. We found genetic variation amon and within the three provenances and the possibility of obtaining high gains from mass selection and individual among and within progenies. The provenance Helenvale showed the best development for DBH, height and volume. The traits DBH, height and volume showed high genetic correlations (> 0.9), indicating the possibility to use the indirect selection. The coefficient of heritability on a progeny mean for the traits DBH and height was median, being 0.31 and 0.30, respectively. The expected genetic gain with the selection were estimated at 12.4% for DBH and 8.5 % for plant height. These results will subsidize the transformation of the provenance and progeny test in a seedling seed orchard and a clonal seed orchard.