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Anne-Marie Brault and Domingos de Oliveira

In `McIntosh' apples (Malus domestica Borkh.), the number of well-formed seeds and the number of fertilized ovules (well-formed plus aborted seeds) were correlated to yield an index of asymmetry for individual fruit. In spite of different flowering and pollination conditions in 1990 and 1991, the index of asymmetry decreased curvilinearly with increases in the number of well-formed seeds and of fertilized ovules in both years.

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Carlos G. Vaz, Domingos de Oliveira, and Orlando S. Ohashi

Cowpea, Vigna unguiculata (L.) Walp., is a very important legume in the diet of the population of the Amazon. Although it is autogamous, this species has a cross-pollination rate of ≈10%. Over several years, the mean productivity of cowpea has declined. We suggest that this is linked to a decrease in or an absence of pollinating insects in the fields. The objective of this study is to ascertain the pollinator contribution to cowpea production, as well as to determine the pollination type of the `BR3-Tracuateua' cultivar. In an experimental design, four treatments were compared: no pollination, with flowers in cages to prevent insect visits; open-pollination, with flowers exposed to all visiting insects; self-pollination, with flowers pollinated with their own pollen; and cross-pollination, with emasculated flowers being pollinated manually with pollen from another plant. We observed higher fruit set in the presence of pollinators (83%) than in their absence (77%, caged flowers). However, cross-pollination reduced both the number of seeds per pod and fruit set relative to self-pollination. This result suggests that pollinators have a complementary role in the yield of cowpea, by creating a mixed pollination system where self-pollination dominates.

Open access

Job Teixeira de Oliveira, Rubens Alves de Oliveira, Domingos Sarvio Magalhães Valente, Isabela da Silva Ribeiro, and Paulo Eduardo Teodoro

Some compaction states cause changes in soil structure, resulting in increased soil density and soil resistance to penetration (RP). The objective of this study was: a) to analyze the variability of the studied attributes of the plant and the soil; b) define the linear and spatial correlations between plant and soil attributes; and c) to identify the best attributes that correlate spatially with garlic yield (GY) and lateral shoot growth (LSG) for the elaboration of spatial variability maps. The attributes evaluated were GY, apparent soil electrical conductivity (EC), mechanical resistance to penetration (MRP), soil volumetric moisture (SVM), plant water potential (WP), and LSG. The reach values of spatial dependence to be considered in future studies using the same attributes should be between 8 m for apparent soil EC and 23 m for RP. From a spatial point of view, garlic LSG could be estimated by indirect cokriging with soil RP. Values greater than 3000 kPa of soil RP indicated the sites with the lowest GYs.

Open access

Job Teixeira de Oliveira, Rubens Alves de Oliveira, Domingos Sarvio Magalhães Valente, Isabela da Silva Ribeiro, and Paulo Eduardo Teodoro

The study aimed to analyze the distribution and spatial autocorrelation of irrigation concerning the other productive components of the garlic crop. The productive components were distributed in thematic maps, and the spatial autocorrelation was estimated by the Moran index, which quantifies the autocorrelation degree. Results show that irrigation contributes to higher yield, with bulbs of larger diameter and heavier cloves. Plants under drought stress conditions tend to develop wider and longer leaves with a higher shoot dry matter. The bivariate analysis revealed that irrigation in garlic is closely related to all explanatory variables.