Relative importance of gene effects for nitrogen-use efficiency in popcorn.

The objective of this study was to evaluate the effects of additive and non-additive genes on the efficiency of nitrogen (N) use and N responsiveness in inbred popcorn lines. The parents, hybrids and reciprocal crosses were evaluated in a 10x10 triple lattice design at two sites and two levels of N availability. To establish different N levels in the two experiments, fertilization was carried out at sowing, according to soil analysis reports. However, for the experiments with ideal nitrogen availability, N was sidedressed according to the crop requirement, whereas for the N-poor experiments sidedressing consisted of 30% of that applied in the N-rich environment. Two indices were evaluated, the Harmonic Mean of the Relative Performance (HMRP) and Agronomic Efficiency under Low Nitrogen Availability (AELN), both based on grain yield at both N levels. Both additive and non-additive gene effects were important for selection for N-use efficiency. Moreover, there was allelic complementarity between the lines and a reciprocal effect for N-use efficiency, indicating the importance of the choice of the parents used as male or female. The best hybrids were obtained from inbred popcorn lines with contrasting N-use efficiency and N responsiveness

Relação da vegetação de caatinga com a condição geomorfométrica local

Objetivou-se, com o presente trabalho, avaliar o potencial das variáveis geomorfométricas extraídas de dados SRTM (Shuttle Radar Topographic Mission) para identificação de tipos vegetacionais da Reserva Particular do Patrimônio Natural de Serra das Almas, CE. Em estudo conduzido na escala de 1:100.000, as variáveis geomorfométricas (elevação, declividade, orientação de vertente, curvatura vertical e curvatura horizontal) foram confrontadas com o mapa de vegetação referência, através de análises de histogramas e análises discriminantes. As variáveis mais importantes na distinção entre os tipos vegetacionais, foram a elevação, a declividade e a curvatura vertical, embora se pudesse observar preferências de tipos mapeados em relação às demais variáveis. Apesar dos dados geomorfométricos mostrarem potencial indicativo das classes de vegetação pela interpretação dos padrões, as análises sob abordagem numérica resultaram em discriminação em um nível aquém do detalhamento temático do mapa referência. Concluiu-se que os dados geomorfométricos representaram significativos insumos para o mapeamento fitogeográfico, devendo ser explorados de forma integrada, em complementaridade às demais variáveis já utilizadas.The objective of this work was to assess the potential of geomorphometric variables, derived from SRTM (Shuttle Radar Topographic Mission) data, to help in identifying vegetation types in the Serra das Almas National Park (CE). A 1:100.000 survey vegetation map was used as reference and the geomorphometric variables (elevation, slope, aspect and profile and plan curvatures) were compared to the mapped units. The variables elevation, slope and profile curvature were shown as the most important for their high discrimination power of the vegetation types. Although geomorphometric data had strong potential for characterizing vegetation through map comparisons, the achieved thematic detail levels were under those of the reference map when data was analyzed under a numerical approach. It was concluded that geomorphometric data were important input for vegetation mapping, and should be employed together with currently used data