The use of supplementary irrigation to sustain the plantation during moments of severe water stress or moments of high water demand is becoming almost a norm to keep sustainable crops, especially due to the climate changes and the high frequency in which climate extremes are occurring lately. The objective of this study was to evaluate the agronomic performance and expression of genetic variability among genotypes of Coffea arabica L. cultivated in farming systems with different levels of water supply, focusing on rainfed or supplementary irrigated systems. The experiment was developed in competition field, testing 8 genotypes of C. arabica L. in rainfed or supplementary irrigated systems. The growth and production were evaluated during 2 consecutive cycles (2014-2015 and 2015-2016). Among the growth gains, it was observed large gains in coffee yield, but the magnitude of the gains varied among genotypes. For crop yield, for example, Paraíso MG/H 419-1 presented 136% gain, while Oeiras MG-6851 was capable of yielding as much more coffee in rainfed conditions than in irrigated system. The expression of variability for some agronomic traits (such as coffee yield, canopy size, growth rate, and number of new buds) may be intensified by the supplementary water supply, which promotes gains in production and growth, increases the magnitude of variation among genotypes and allows to identify different patterns for selection, which may not be observed in the rainfed systems.

Open Access Agricultural Journals published by Institute of Agricultural Economics and Information

With the water crisis affecting several countries, the use of innovative technologies and methods in irrigated agriculture is essential to increase water use efficiency. The use of magnetised water has been considered a possibility both for saving water resources and in increasing crop productivity and quality. Following this, the objective of the present study was to evaluate the growth and longevity of flower stems of ornamental sunflower ( Helianthus annuus L.; Vincent’s Choice) irrigated with different irrigation depths and water subjected to magnetic field treatment. The treatments consisted of five percentage of crop evapotranspiration (ETc) (20, 70, 100, 130, and 160% of ETc) and two types of irrigation water (magnetised water; and ordinary water). The following characteristics were evaluated: plant height, stem diameter, inflorescence diameter, fresh and dry masses of the leaves and stems, fresh and dry masses of the inflorescence, and post‐harvest longevity of the flower stems. The growth and post‐harvest longevity characteristics were not influenced by the water type. An increase in irrigation depth promoted an increase in all analysed parameters. Regarding the commercialisation patterns of cut flowers, depth equal to or greater than 0.7 ETc yielded the best classification of ornamental sunflower.

Studies quantifying the effect of the nitrogen over the growth of genotypes of Conilon coffee contribute to improve the fertilization management. Thus, this study was developed to evaluate the growth of improved genotypes of Coffea canephora Pierre ex Froehner submitted to nitrogen fertilization. Six improved genotypes of C. canephora, from different groups of ripening cycles, were grown without nitrogen fertilization or with fertilization at level of 0.625 g kg-1 of soil, cultivated in greenhouse, following a completely randomized design, with four replications. The plant growths were evaluated considering the plant height, stem diameter, number of leaves and relative growth rate. Nitrogen fertilization was able to promote higher growth, as well as, in general, a higher relative growth rate of all genotypes. Differentiation among genotypes was observed for their responses to each of the evaluated parameters. Noteworthy are the genotypes 77, in leafiness, and 67 in plant height and stem diameter, which presented higher growth compared to other genotypes, with or without nitrogen fertilization. Key words: Coffea canephora, response, deficiency, mineral nutrition.

The multi-stem aspect of crop systems using Coffea canephora makes it necessary to correctly establish the number of orthotropic stems per plant during the crop formation. The present study was developed to study the variability of responses among improved genotypes of C. canephora to the technique of bending orthotropic stems as a mean of promoting the sprout growth, allowing producing an adequate number of vigorous sprouts that will be conducted to create the multi-stem canopies. The experiment studied 27 improved genotypes of C. canephora, following a randomized block design, with four replications and six plants per experimental plot. The results show that growth pattern and responsiveness varies among genotypes, and that parameters of biomass allocation and leafiness seems to be good describers to study of genetic variability. The observed variability was enough to cluster the genotypes regarding their response to this technique and to identify groups of genotypes with higher similarity and homogeneous behavior. It is important to identify genotypes from groups of slower growth (e.g., 102, 103 and 301) or lesser emission of new sprouts (e.g., 207 and 301), since these may require additional treatments to develop the adequate number of orthotropic stems in the multi-stem architecture.