The data analyzed in this study showed that the AMMI1 and GGE biplot methods are equivalent to rank genotypes for stability and adaptability.

Penetration resistance can be determined directly in the field or in the laboratory. However, data obtained using the two methods are not directly comparable. Considering soil moisture influences penetration resistance, penetration resistance data obtained using the two methods can be corrected based on common moisture values. To enable comparison of the data, the measured data should be adjusted using mathematical models. Consequently, the objective of the present study was to compare soil penetration resistance values measured in a Red Latosol using a static penetrometer and a bench-top electronic penetrometer. The comparison was carried out using samples collected from different soil layers, based on moisture levels ranging from 0.15 to 0.28 kg kg-1. In addition, the reliability of some mathematical models was compared using benchpenetrometer data. Finally, the Busscher method and a new proposed method for moisture correction were tested. According to the comparison of results between the equipment, it is necessary to correct data using a linear type equation. The Jakobsen & Dexter (1987) model had the optimal performance (R 2 : 0.89; RMSD: 0.70). The new proposed corrected method was tested using several reference moisture values and it presented minor (< 0.30 RMSD) and stable errors.

RESUMO-Algumas espécies de citros apresentam produção irregular ao longo dos anos. Além da safra irregular, a alternância de produção pode interferir na qualidade dos frutos, característica cada vez mais valorizada pelo mercado citrícola. O objetivo do trabalho foi avaliar o efeito da carga pendente na qualidade dos frutos da laranjeira 'Valência'. O experimento foi conduzido com laranjeiras 'Valência' enxertadas em tangerineiras 'Cleópatra' em condição de campo. Em janeiro de 2007, metade das plantas teve todos os seus frutos retirados, enquanto a outra metade permaneceu intacta. As plantas que tiveram seus frutos retirados apresentaram, em setembro de 2007, floração mais intensa e, portanto, uma Alta Carga de frutos (AC, 752 frutos/árvore) em 2008, quando comparadas às plantas que não tiveram seus frutos retirados, que apresentaram Baixa Carga de frutos (BC, 317 frutos/árvore). Os frutos maduros, colhidos em dezembro de 2008, foram analisados quanto à massa, teor de sólidos solúveis, acidez titulável, espessura e cor da casca, teor de suco e número de sementes. Na safra seguinte, de 2009, as avaliações das características físico-químicas dos frutos foram repetidas nas mesmas árvores, mas durante quatro momentos entre o período de frutificação e a colheita, em novembro de 2009. Na safra de 2008, houve diferença na massa individual dos frutos com valores de 172 e 158g nas plantas BC e AC, respectivamente. O teor de sólidos solúveis, acidez titulável, teor de suco nos frutos, espessura da casca e o índice tecnológico foram semelhantes entre os tratamentos, nas safras de 2008 e 2009. Entretanto, vale considerar que, como a produção de frutos nas plantas AC, na safra de 2008, foi 2,2 vezes maior se comparada às das plantas BC (AC: 2,9 caixas/planta e BC: 1,3 caixa/planta), a quantidade total de sólidos solúveis produzida por planta também foi maior. Não houve influência da carga pendente de frutos no teor de açúcares (glicose, frutose e sacarose) no suco e na cor da casca durante o desenvolvimento dos frutos. Apesar de reduzir a massa do fruto, a diferença de carga pendente observada em laranjeira 'Valência' não influenciou na qualidade dos frutos quando considerado, como destino da fruta, a indústria citrícola. Termos para indexação: Citrus sinensis,carboidratos, laranja, alternância de produção. EFFECT OF CROP LOADING ON QUALITY OF 'VALENCIA' ORANGE FRUITABSTRACT -Some citrus species show irregular production over the years. Besides the irregular crop yield, alternate bearing may affect the fruit quality, a characteristic that is increasingly valued by the citrus market. The aim of the work was to evaluate the effect of crop load on fruit quality of 'Valência' orange trees. The experiment was carried out under field conditions with 'Valência' orange scions grafted on 'Cleópatra' mandarin rootstocks. In January 2007, half of the plants were defruited, while the other half remained intact. boxes/plant and BC: 1,3 boxes/plant), total soluble solids produced per plant was also higher. Crop load did not affect the sug...

Subsurface soil compaction and nutritional stress are among the main factors that limit the yield of crops. Using forest residues, such as wood ash, is a viable option in the chemical recovery of soils and can promote vigorous root development in soils with subsurface compaction. The objective of this study was to indicate the most adequate dose of wood ash for efficient management of this residue applied in rotational crops cultivated in soils with subsurface compaction. Safflower plants (Carthamus tinctorius), a rotational crop with a deep taproot system, were grown in clay soil fertilized with different doses of ash and with induced levels of compaction in the subsurface layer. The experiment was conducted in a randomized block design, under a 4 × 5 factorial scheme, composed of four doses of wood ash (8.0, 16.0, 24.0, and 32.0 g dm-3) and five levels of soil bulk density (1.0, 1.2, 1.4, 1.6, and 1.8 kg dm-3), with four replicates. Crop growth variables (plant height, number of leaves, stem diameter, and SPAD chlorophyll index) were evaluated at 15, 45, and 75 days after emergence. The results indicated that soil compaction was the most limiting factor to the vegetative development of safflower, regardless of the ash dose. The interaction between the wood ash dose and bulk density, when present, showed that the best growth response occurred for ash dose of 25 g dm-3 for a soil bulk density of 1.2 kg dm-3.

The quality of cherry tomato fruits is directly related to the management strategies used in the production system, such as irrigation and fertilization. This study aimed to assess the quality of cherry tomato fruits cultivated under water availability and potassium fertilization. The experiment was carried out in a greenhouse in pots of 12 dm 3 of an Oxisol. The experimental design was a randomized block design in a 5 2 fractional factorial arrangement with five water availabilities in the soil (4, 14, 24, 34, and 44-kPa), five potassium doses (0, 125, 250, 375, and 500 mg dm-3) and with four blocks. Irrigation was performed with a semi-automated drip irrigation system with soil moisture monitoring by the Diviner 2000 ® capacitance probe. The assessed variables in fruits were longitudinal and transversal diameter and pulp thickness, fruit shape index, total soluble solids (SS), titratable acidity (TA), the SS/TA ratio, and vitamin C. The data were submitted to statistical analyses at 5% probability error, with analysis of variance by the F-test and polynomial regression. Fruit size presents a reduction as water availability decreased. The total soluble solids have a higher concentration at a potassium dose of 326 mg dm-3. The quality of cherry tomato fruits cultivated in an Oxisol is influenced by water availability and potassium doses.