The objective of this study was to evaluate the nutritional efficiency of phosphorus in clones of conilon coffee, in greenhouse condition. A factorial design 13 x 4 was used, with three replications, and the factors being: 13 clones that compose the clonal cultivar "Vitória Incaper 8142" and four levels of phosphorus fertilization (0%, 50%, 100% and 150% of the recommended P 2 O 5 for the culture) in a completely randomized design (CRD). The cultivation consisted of a period of 150 days, then in each experimental unit, the values of dry matter and phosphorus content of the vegetative parts were obtained. The indices of nutritional efficiency (absorption, translocation and utilization) were calculated. The clones of conilon coffee showed different behavior for all variables at each level of fertilization with P 2 O 5 . The mass of dry weight, phosphorus content, and efficiency of phosphorus utilization of the clones increase linearly with the increase of P 2 O 5 . The efficiency of phosphorus absorption, depending on the levels of P 2 O 5 applied to the clones of conilon coffee, has set to a quadratic model. The translocation efficiency of phosphorus, depending on the levels of P 2 O 5 applied, is different for clones of conilon coffee, with a linear characteristic and also quadratic.
The objective of this study was to evaluate the nutritional efficiency of phosphorus in physic nut (Jatropha curcas L.) genotypes, under controlled conditions. The experiment was arranged in a randomized block design, in a factorial scheme 10 x 2, using ten physic nut genotypes, two levels of phosphorus available in the soil (10 and 60 mg dm-3), and four replications. Cultivation consisted of a period of 100 days, with vegetative growth being evaluated in each experimental plot, with the dry matter mass values, phosphorus contents in the vegetative parts, nutritional efficiency indices, and alpha parameter also being obtained. The results show that the physic nut genotypes present greater vegetative growth, dry matter mass accumulation, P content, absorption efficiency and translocation at the high level of phosphorus available in the soil. Genotype CNPAE-C2 is the most efficient and responsive to phosphoric fertilization
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.
ABSTRACT. The present study was developed to respond to the need for an increase in crop yield in the mountain region of Caparaó (southern Espírito Santo State, Brazil), an area of traditional coffee production. This study aimed to analyze the diversity and characterize the crop yield of genotypes of Coffea arabica L. with potential for cultivation in high plant density systems. In addition, it also aimed to quantify the expression of agronomic traits in this cultivation system and provide information on the genotypes with the highest cultivation potential in the studied region. The experiment followed a randomized block design with 16 genotypes, four repetitions, and six plants per experimental plot. Plant spacing was 2.00 x 0.60 m, with a total of 8333 plants per hectare, representing a high-density cultivation system. Coffee plants were cultivated until the start of their reproductive phenological cycles and were evaluated along four complete reproductive cycles. Genotypes with high crop yield and beverage quality, short canopy, and rust resistance were selected. C. arabica genotypes showed variability in almost all characteristics. It was possible to identify different responses among genotypes grown in a high plant density cultivation system. Although the chlorophyll a content was similar among genotypes, the genotypes Acauã, Araponga MG1, Sacramento MG1, Tupi, and Catuaí IAC 44 showed a higher chlorophyll b content than the other genotypes. Among these, Sacramento MG1 also showed high leafiness and growth of vegetative structures, whereas Araponga MG1, Pau-Brasil MG1, and Tupi showed high fruit production. In addition, Araponga MG1 had also a higher and more stable crop yield over the years.
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