Yield Of Commercial Roots Research Articles

Influencia de la fertilización inorgánica sobre parametros productivos de dos variedades de camote

In order to determine the effect of inorganic fertilization treatments on the productive behavior of the sweetpotato varieties "INIAP-Toquecita" and "INIAP-Buena Vista", this research was carried out during the dry season (June–December 2022) at the Estación Experimental Portoviejo del Instituto Nacional de Investigaciones Agropecuarias-INIAP, in the Colón parish, canton Portoviejo, province of Manabí, Ecuador. A randomized complete block design was used with three replications, and the following variables were analyzed: percent yield, total number of guides per plant, length of guides, mass of 100 guides, foliage yield, and number and yield of commercial roots. The inorganic fertilization treatments under study were: 1. N+P2O5+K2O+S+Mg+B; 2. N+P2O5+K2O+S+Mg+B+Zn+Mn+Fe; 3. 50 % more N+P2O5+K2O+S+Mg+B with respect to treatment 1; 4. N+P2O5+K2O; and 5. no fertilizers (control). It was evidenced that the inorganic fertilization treatments implemented on the variety "INIAP-Buena Vista" outperformed the results of the control, while treatments 1 and 2 of inorganic fertilization implemented on the variety "INIAP-Toquecita" outperformed the control. It was observed that the most favorable scenario for maximizing the yield of commercial tuberous roots in the variety "INIAP-Buena Vista" was treatment 3, which had 50 % more macro and micronutrients per hectare added to the soil with respect to treatment 1. The varieties evaluated did not show nutritional deficiencies during the production cycle (120 days).

Produção e qualidade física de batata-doce sob adubação fosfatada

ABSTRACT Phosphorus (P) is a primordial mineral nutrient for plants, as it is directly linked to physiological and biochemical processes essential for plant maintenance, and can influence the production and final quality of the product. Furthermore, P favors good root development, which can benefit sweet potato crop. Thus, the objective of the work is to assess the influence of increasing doses of P on the production and physical quality of sweet potatoes in two growing seasons in a semi-arid environment. The experiments were carried out from April to August 2021 (season 1) and from December 2021 to April 2022 (season 2) at the Rafael Fernandes Experimental Farm - UFERSA, Mossoró, RN, BR. The design was randomized blocks, with four replications. The treatments consisted of five doses of P (0; 60; 120; 180 and 240 kg ha-1 of P2O5) via fertigation and tested on the sweet potato cultivar Paraná. After harvesting the roots, the number and yield of roots (commercial, non-commercial and total), the average mass and the percentage of commercial roots were evaluated. Commercial roots were evaluated for firmness, elasticity and cooking time. The P doses influenced the production characteristics, mainly at the dose of 60 kg ha-1 of P2O5, which promoted increases in the yield of commercial roots. The doses of P promoted the reduction of firmness for both growing seasons. A dose of 180 kg ha-1 of P2O5 led to the shortest cooking time for the second growing season.

CARACTERÍSTICAS AGRONÔMICAS, COZIMENTO E CONSERVAÇÃO PÓS-COLHEITA PARA SELEÇÃO DE CLONES DE MANDIOCA DE MESA

ABSTRACT The objective of this work was to evaluate the agronomic performance, cooking time and postharvest conservation of roots of sweet cassava clones, to select those superior to the Manteiga variety control, in the Baixo Sul region of Bahia state. A randomized block design in split plot scheme, with three replications was used. Eleven genotypes were evaluated at 10 and 12 months after planting. Considering the mean of two harvests, BRS Kiriris and Saracura showed total root yield (39.85 and 33.91 t ha−1, respectively) and commercial root yield (26.54 and 26.71 t ha−1) that are higher compared to Manteiga (total root yield: 28.06 t ha−1, commercial root yield: 16.95 t ha−1). However, both had cooking time (26.76 and 28.30 min, respectively) higher than that of Manteiga (23.89 min), and BRS Kiriris was unstable regarding the cooking percentage between 10 (91.67%) and 12 months (50%). BRS Aipim Brasil, 2003 14-11, BRS Kiriris, Eucalipto, Saracura and Manteiga were more tolerant to postharvest physiological deterioration. Although some of the evaluated clones presented good performance in the evaluated traits, by analyzing the set of traits, none of them shows sufficient superiority to be indicated as a potential substitute for Manteiga, grown in the Baixo Sul region of Bahia state.

Selection of superior sweet potato genotypes for human consumption via mixed models

The growing consumer demand for sweet potato roots results in the need for genotypes with higher yields and better root quality. Thus, the objective of this study was to agronomically evaluate sweet potato genotypes via mixed models to select superior genotypes for human consumption and predict their selection gains. The study had a partially balanced triple lattice design with three replicates. As treatments, 92 sweet potato genotypes from the Universidade Federal de Lavras germplasm bank selected in the first selection cycle were evaluated along with eight controls, namely, Brazlândia Roxa, Princesa, Uruguaiana, BRS Amélia, Beauregard, UFVJM-57, UFVJM-58, and UFVJM-61. The treatments were ranked by the mixed linear model via restricted maximum likelihood (REML) and best linear unbiased prediction (BLUP). We highlighted the 15 best genotypes for each agronomic trait, then identified the best ones overall considering all quantitative and qualitative traits. High heritability was found for the trait commercial root yield (56.31%). For all traits, there were selection gains relative to the population mean. The use of mixed models was efficient for the selection of superior sweet potato genotypes. The genotypes 2018-19-464, 2018-72-1409, 2018-72-1428, 2018-19-443, 2018-36-807, 2018-72-1418, 2018-19-455, 2018-72-1376, 2018-54-1137, 2018-54-1114, 2018-65-1249, and 2018-28-556 have good traits related to commercial root yield and root quality and may be recommended for human consumption.

ECONOMIC VIABILITY OF BEET CROPS USING Calotropis procera BIOMASS AS SOIL FERTILIZER IN TWO GROWING SEASONS1

ABSTRACT The use of green manure from spontaneous species has gained prominence for vegetable crops focused on environmental sustainability and is an alternative method for the Semiarid region in the Northeast of Brazil. Two experiments were conducted in two growing seasons (autumn and spring-summer), in Serra Talhada, PE, Brazil, to evaluate the effects of different amounts of biomass of Calotropis procera (roostertree) and incorporation times on the agro-economic performance of beet crops. A randomized block experimental design was used, with three replications, in a 4 × 4 factorial arrangement; the first factor consisted of amounts of C. procera biomass (5.4, 8.8, 12.2, and 15.6 Mg ha-1 on a dry basis) and the second factor consisted of times of incorporation into the soil (0, 10, 20, and 30 days before planting beet). Commercial root yield, production costs, and the following economic indicators were determined: gross income, net income, return rate, and profitability index. The use of 15.6 Mg ha-1 of C. procera biomass resulted in the highest gross and net incomes and the use of 5.4 and 12.2 Mg ha-1 resulted in the best return rates and profitability indexes in autumn and spring-summer seasons, respectively; the planting time was considered as ideal for the biomass incorporation. The spring-summer growing season resulted in a higher economic return than the autumn growing season. The use of C. procera as a green manure for beet production is economically viable, regardless of the factors evaluated.

Bayesian approach to estimate genetic parameters and selection of sweet potato half-sib progenies

The selection of progenies in breeding programs can generate great advances when associated with Bayesian inference because it allows the incorporation of a priori knowledge. Selection at self plant level is advantageous when evaluating half-sib progenies. However, it becomes very difficult for sweet potato cultivation are expected to support the improvement of sweet potato populations. In this context, BLUPIS (best linear unbiased prediction individual simulated) becomes an good alternative technique. Therefore, this study aimed to use the a priori knowledge obtained in previous sweet potato experiments through Bayesian inference to estimate genetic parameters and gains from selection and afterwards to choose the better half-sib progenies considering the BLUPIS. Sixteen progenies were evaluated for root and branch yield, root shape, and resistance to soil insects. The data were analyzed using Bayesian theory, considering data from 12 previous experiments to obtain the informative a priori. All variables tested, as total root yield, commercial root yield, branch green mass yield, average weight of commercial roots, root shape e resistance to soil insects showed high values for coefficient of heritability. Expressive gains are expected to support the improvement of sweet potato populations. This applied methodology, will be allowed breeders to re-design and select the most promising progenies during all breeding process for improve well determined and specific traits in sweet potato.

Genetic diversity among cassava genotypes (Manihot esculenta crantz) collected in the south-central mesoregion of the state of Mato Grosso-Brazil

The aim of this research was to evaluate the genetic divergence between 164 genotypes of Manihot esculenta from the South-Central mesoregion of the State of Mato Grosso. The genotypes are from projects conducted by the Laboratory of Genetic Resources & Biotechnology of the University of the State of Mato Grosso, Cáceres-Mato Grosso (UNEMAT), and the Brazilian Public Agricultural Research Corporation - Agrosilvopastoral (EMBRAPA). The agronomic descriptors evaluated were plant height, height of first branching, branching levels, weight of the aerial part of the plant, total weight of the plant, number of roots per plant, average weight of roots per plant, yield of commercial roots, yield of non-commercial roots, number of rotten roots per plant and harvest index. For the analysis of genetic divergence, multivariate analysis based on the standardized Euclidean mean distance was employed, later performing the Hierarchical UPGMA and Tocher Optimization agglomerative methods. The degree of preservation of the genetic distances in the dendrogram was verified using the Cophenetic Correlation Coefficient. The Singh criterion was used to quantify the relative contribution of characteristics to genetic divergence. The genotypes presented genetic dissimilarity for the evaluated characteristics and based on the results of the dissimilarity matrix and groupings, it is recommended the crossings between the genotypes allocated in group II with the genotype allocated in group V, for the development of segregated populations with high genetic variability.

Weed control with preemergence Ametryn in Arracacia xanthorrhiza

Two experiments were performed from 1985 to 1987 at Barranquitas in a Humatas soil to evaluate Ametryn (Evik 80 W) for preemergence control of weeds in Peruvian carrot or arradacha (Arracacia xanthorrhiza Banc). Five treatments were evaluated: Ametryn at 4.98, 8.97 and 17.94 kg ai/ha; a hand-weeded check (hoeing); and non-weeded check. There were significant differences (P ± 0.05) in the yield of commercial roots in the first experiment only between the non-weeded plots (7.00 t/ha) and Ametryn plots at 8.97 kg ai/ha (21.68 t/ha) whereas in the second trial, differences were observed between the hand-weeded (14.18 t/ha) and the non-weeded plots (4.11 t/ha). A considerable reduction in the second experiment was probably due to the fact that plants were harvested two months earlier (at 7 months) than in the first experiment, and some root damage was due to rats. Mean yields were 16.68 and 9.78 t/ha of commercial roots in experiments 1 and 2, respectively. These results showed that weed competition can reduce yields in arracacha by more than 60%. Good to excellent weed control with Ametryn was obtained at 12 weeks, when the arracacha foliage should have covered all soil surface area. There was 35% (first experiment) and 0.53% (2nd experiment) of weed coverage in the plots where Ametryn was applied at the lowest rate, 4.48 kg ai/ha. Herbicide efficiency increased with higher rates in both experiments. No toxic effects on the plants were observed from evaluations made 4 and 8 weeks after the treatments. Data obtained from these experiments showed that Ametryn was highly efficient in controlling weeds in arracacha up to 12 weeks even at the lowest application rate. The information obtained is valuable for obtaining registration of this pesticide for this crop.

Intercropping of beet with salad rocket (Eruca sativa) using hairy woodrose (Merremia aegyptia) plus manure goat in loam argisol yellow red latosol

The crop intercropping is a viable option for family farmers who grow in small spaces and need to take advantage of all the available area. The objective of this study was to evaluate the agronomic viability of the intercropping of beet with salad rocket (arugula) under different amounts of Merremia aegyptia plus goat manure. The experiment was conducted at Rafael Fernandes Experimental Farm, in the Alagoinha district, rural area of Mossoró-RN, from August to December 2016. The experimental design was a randomized complete block with treatments arranged in a 2 x 4 factorial scheme, with three repetitions. The first factor was the single beet and second intercropped cultivation of beet and arugula. The second factor was the amount of Merremia aegyptia plus goat manure (0.0, 1.5, 3.0 and 4.5 kg m-2). For the sugar beet crop the following characteristics were evaluated: plant height, fresh leaf mass, commercial root yield and root dry mass. For arugula culture the following characteristics were evaluated: plant height, number of leaves per plant, yield, number of sauces and dry mass. The best agronomic performance of the beet and rocket intercropping was obtained in the amount of 4.5 kg m-2 of M. aegyptia beds and goat manure. The consortium presented an area ratio equivalent to over 1.0, with an average value of 1.81 in the amount of 4.5 kg m-2 of M. aegyptia flowerbed plus goat manure. The consortium contributed to better use of available resources without compromising the commercial quality of the vegetables

LA PRODUCCIÓN DE SEMILLAS Y RAÍCES DEL CULTIVO DE YUCA SE MANTIENE BAJO DIFERENTES DENSIDADES DE SIEMBRA: UN ENFOQUE AGROECOLÓGICO

<p><strong>Background: </strong>Cassava (<em>Manihot esculenta</em> Crantz) is the fifth most important crop in the world and has a fundamental role in food security in most tropical countries. However, studies are still needed to improve its management and production. <strong>Objective</strong>: the objective of this study was to evaluate the effect of planting density on the pattern of allocation of aboveground and belowground biomass, and asexual seeds production of the cassava crop (Cultivar Armenia) in Cucururital, Átures municipality, Amazonas state, Venezuela. <strong>Methodology</strong>: A total of 25 10 × 10 plots (100 m2) were established under a randomized block design with five replicates and five treatments to compare different parameters of growth and production of the cassava crop under different conditions of planting density: 1.20 × 0.60 m (T1), 1.20 × 0.80 m (T2), 1.20 × 1 m (T3), 1.20 × 1.20 m (T4), and 1.20 × 1.40 m (T5). <strong>Results</strong>: The results of this research show that there are no significant differences in relation to the different growth and production parameters between the planting density treatments. Despite the variations in planting densities evaluated in this study (5952 to 13888 plants ha<sup>-1</sup>), the yield of commercial roots (400 to 500 kg plant-1) as the main parameter of agronomic importance, was relatively high compared to different tropical and national studies. <strong>Implications</strong>: These results allow us to infer that this cassava crop (Armenia) has a high adaptation, phenotypic plasticity and production potential under different growth conditions, which may be advantageous from an agro-ecological, economic and social point of view, to contribute with food security and sustainable livelihoods. <strong>Conclusion</strong>: With this applied research it was possible to demonstrate the production potential of roots and asexual seeds of the cassava crop (cultivar Armenia) despite the variation in planting density in previously degraded agricultural areas, where no statistical differences were observed between treatments.</p>

YIELD OF MARGARET QUEEN RADISH HYBRID ACCORDING TO THE SPACING

Currently, some important hybrids have replaced traditional radish cultivars, without, however, developing necessary studies on the best planting density for different Brazilian conditions. Thus, the present study aimed to evaluate the effect of spacing between rows and plants on the development and yield of the ‘Margaret Queen’ radish hybrid. A randomized blocks experimental design with four replications in a 3 x 3 factorial scheme was used. Three row spacings (10, 15, and 20 cm) and three spacings between plants in the row (3, 6, and 9 cm) were evaluated. The seeds were sown in furrows at 1.0 cm deep, and the harvest was carried out at 28 days after sowing. The following were determined: number of leaves, root diameter, root length, average root weight, non-damaged root yield, damaged root yield, commercial root yield, and non-commercial root yield. The row spacing did not influence the development of the plants, but it affected the root yield. The row spacing of 20 cm had the lowest root yield. The spacings that provided the highest commercial root yield (D>30 mm) of the Margaret Queen radish hybrid were 10 and 15 cm between rows and 6 cm between plants. The 3 cm spacing between plants is the least suitable for the cultivation of the Margaret Queen radish hybrid radish under the studied conditions.

Association between agronomic characters and hay quality of sweet potato branches

ABSTRACT From the perspective of the use of sweet potato branches for animal feed, there is a lack of information on the influence of this action on hay quality. Therefore, the objective was to study the association of sweet potato yield attributes with chemical-bromatological characteristics of hay. Ten sweet potato clones were evaluated, conducted in randomized blocks with five replications. Green and dry mass yield, dry mass content, leaf and stem ratio, total and commercial root yield, and chemical and bromatological characteristics of hay from the branches were determined. Phenotypic correlation and trial analysis between characteristics were estimated. Selection for the highest yield of roots and commercial roots may provide increased hay of crude protein, neutral detergent fiber and acid and total soluble sugars. However, selection for the highest root yield has a negative effect on the starch content of hay and deserves special attention from the breeder.

Improving productivity of orange-fleshed sweetpotato (Ipomoea batatas) through intercropping with legumes and moderate phosphorus application

Sweetpotato yield is adversely affected by poor soil fertility in Mozambique where access to inorganic fertilisers is lacking. The objective of the study was to evaluate the effectiveness of intercropping sweetpotato with groundnut and soybean at various phosphorus (P) fertilisation levels on the productivity of sweetpotato. A field experiment was conducted at Umbeluzi Research Station in southern Mozambique during the 2013/14, 2014/15 and 2015/16 growing seasons. The experimental design was a split plot with seven crop combinations and three P levels (0, 20 and 40 kg P ha−1). Phosphorus at 20 and 40 kg ha−1 produced best total storage yield, total biomass and commercial root yields, whereas P at 40 kg ha−1 favoured highest vegetative growth. Sweetpotato–groundnut intercropping produced the best commercial root yield and total biomass. Phosphorus applied at 40 kg ha−1, combined with sweetpotato and groundnut intercropping, produced the highest total and commercial storage root yield but these two parameters were not significantly different from sweetpotato–groundnut intercropping at 20 kg P ha−1. For farmers growing sweetpotato under similar climatic and soil conditions, we recommend intercropping with ground-nuts and additional application of 20 kg P ha−1 for farmers with fertiliser access.

STUDY OF THE RAPHANUS SATIVUS L. (SMALL RADISH) BIODIVERSITY UNDER CONDITIONS OF INTENSIVE LIGHT-CULTURE AND IDENTIFICATION OF DONORS OF ECONOMICALLY LUABLE CHARACTERS FOR BREEDING

Supply of the domestic fresh vegetables commodity to the population of Northern regions of Russia is one of the most priority tasks of the national economy. Lack of the local, high-quality and adopted breeding material is highly problematic for breeding programs. Generation of the new, highly productive vegetable cultivars for the glass-covered ground, including light culture, will promote to expand significantly the volume of local production of vegetables in protected ground, especially in regions with a cold climate. One of the most prospective crops for protected ground is small radish, an early ripening crop with a valuable biochemical composition. А strategy for creation of the new, highly productive forms of small radish, beard predictable complex of economically valuable characters for growing in conditions of intensive light culture, has been developed in the Agrophysical Research Institute (SaintPetersburg). At the first stage, represent interspecific set of 26 small radish cultivars from different regions, was investigated in controlled conditions (artificial light, climate cell) to reveal a complex of economically valuable properties (early maturity, productivity, morphological traits). The plants were grown in original plant grooving light equipment (lamps DNaZ-400, photoperiod 12 hours, irradiation 15-20 klk), in a small volume of substrate (peat with mineral additives). It was observed that the small radish varieties have significant diversity in precocity, productivity, resistance to bolting, also they vary in a number of morphological features of roots and leaves. Bov, Estella, Rocco (Netherlands), Nobo Chind Criollo (Peru) were the most productive cultivars. They can produce yield of commercial roots during 30 days of vegetation up to 3.5 kg/m2. In addition, cultivars – genetic resources of economically valuable properties (compact rosette, glabrous leaf, resistance to bolting) were revealed for a breeding. Parent pairs for crossing were selected. It is planned to obtain offspring small radish forms with a complex of economically valuable properties, more productive than the parents. In all matched hybrid combinations, F1 hybrids were obtained. They have a degree of hybrid superiority in roots weight from 110 to 230% over the best of the parent form. They will become the ancestors of the original forms of small radish, intended for cultivation in conditions of intense light culture.

Carrot root size distribution in response to biostimulant application

ABSTRACTIn 2009–2011, in Poland (53°13′N, 17°51′E), field experiments were conducted concerning the influence of biostimulants Kelpak SL and Asahi SL on the size grades of yield of carrot cv. ‘Karotan’. Kelpak SL is produced from seaweed Ecklonia maxima; Asahi SL is composed of nitrophenols. Biostimulants were sprayed from fourth-leaf stage of carrot, once, twice or three times in growing period. Seaweed extract was used at total doses of: 0, 2, 3, 4, 5, 6 and 7 l ha−1, while Asahi SL at 1 l ha−1. It was found that biostimulants had a favourable effect on total and commercial root yield, but this effect was dependent on the type of preparation, the dose, the time and the number of treatments. The best results in increasing the commercial yield were achieved after a single application of Kelpak SL at doses 2 or 3 l ha−1 at the fourth-leaf stage (13.1% and 12.4% respectively, compared to the control). Both biostimulants Kelpak SL and Asahi SL positively affected the root size distribution by increasing the yield of medium roots (1.9–3.8 cm in diameter) as well as large roots (3.8–5.0 cm), by 30.5% and 15.8%, respectively.

Densidade de plantio na cultura da cenoura no Submédio do Vale do São Francisco

A cenoura é a quarta hortaliça mais consumida no país e uma das mais consumidas no mundo. Com o objetivo de avaliar o desempenho produtivo da cenoura em diferentes espaçamentos de plantio conduziu-se um experimento no período de outubro de 2013 a fevereiro de 2014. Utilizou-se o delineamento de blocos ao acaso em esquema fatorial 2 x 4, consistindo em dois espaçamentos entre linhas (20 e 25 cm) e quatro espaçamentos entre plantas (4, 6, 8 e 10 cm) com três repetições e utilizando a cultivar Brasília. A altura das plantas oscilou de 52,1 a 53,3 cm para os espaçamentos entre linhas e de 51,0 a 53,2 cm nos espaçamentos entre plantas, não se verificando diferenças significativas. Produtividade comercial de raízes superior foi obtida para o espaçamento de 20 cm entre linhas (40,6 t ha-1), em comparação ao espaçamento de 25 cm entre linhas (35,4 t ha-1). O espaçamento 4 cm entre plantas linhas apresentou maior rendimento de raízes comerciais (44,5 t ha-1). Maior massa fresca de raízes foi observada nos maiores espaçamentos entre linhas e plantas. À medida que se aumentou a população de plantas houve um acréscimo no percentual de raízes de maior comprimento e redução percentual de raízes mais curtas.

Performance of carrot genotypes at two Jequitinhonha Valley sites

<p>The successful commercial use of carrot depends on the choice of cultivars that are well-adapted to soil and climate conditions at the cultivation site and on good consumer acceptance. The objective of this study was to evaluate the performance of carrot cultivars grown in autumn-winter in two towns with different climatic characteristics, in the High Jequitinhonha Valley, MG, Brazil. The experiments were conducted on the Rio Manso farm, in the town of Couto de Magalhães de Minas and on Campus JK at UFVJM, in the town of Diamantina, Minas Gerais, Brazil. Six carrot cultivars (Brasília, Nantes, Kuronan, Esplanada, Planalto and Tornado) were evaluated using a randomized complete block design with three replicates. The following morpho-agronomic characteristics were evaluated 100 days after sowing: shoot height, root length, root dry matter, total dry matter, harvest index, commercial yield and total yield root. The most suitable cultivars in Diamantina were Planalto, Tornado and Kuronan, and the cultivatar Planalto was the best suited to Couto de Magalhães de Minas. The agronomic performance of the cultivars was higher in Couto de Magalhães de Minas for the majority of the study variables, resulting in a higher total yield and commercial root yield. The climatic and soil conditions of Diamantina induced flowering in most cultivars, causing a loss to the commercial yield in autumn-winter cultivation.</p>

Performance of carrot genotypes at two Jequitinhonha Valley sites

The successful commercial use of carrot depends on the choice of cultivars that are well-adapted to soil and climate conditions at the cultivation site and on good consumer acceptance. The objective of this study was to evaluate the performance of carrot cultivars grown in autumn-winter in two towns with different climatic characteristics, in the High Jequitinhonha Valley, MG, Brazil. The experiments were conducted on the Rio Manso farm, in the town of Couto de Magalhães de Minas and on Campus JK at UFVJM, in the town of Diamantina, Minas Gerais, Brazil. Six carrot cultivars (Brasília, Nantes, Kuronan, Esplanada, Planalto and Tornado) were evaluated using a randomized complete block design with three replicates. The following morpho-agronomic characteristics were evaluated 100 days after sowing: shoot height, root length, root dry matter, total dry matter, harvest index, commercial yield and total yield root. The most suitable cultivars in Diamantina were Planalto, Tornado and Kuronan, and the cultivatar Planalto was the best suited to Couto de Magalhães de Minas. The agronomic performance of the cultivars was higher in Couto de Magalhães de Minas for the majority of the study variables, resulting in a higher total yield and commercial root yield. The climatic and soil conditions of Diamantina induced flowering in most cultivars, causing a loss to the commercial yield in autumn-winter cultivation.

Response of yams exposed to different sources and doses of nitrogen fertilizers in the State of Maranhão, Brazil

This study was carried out at the State University of Maranhão, São Luís, Brazil from January to November 2012. We assessed the behavior of the yam Dioscorea cayenensis ‘Da Costa’, fertilized with different rates and sources of nitrogen (N). The experimental design was randomized, with treatments in a 6 × 2 factorial design. The factors were represented by six rates of N fertilization (0, 50, 100, 150, 200, and 250 kg·ha-1) and two sources (ammonium sulfate and urea) by using four replicates. We evaluated the mean mass, commercial root yield, leaf N content, starch content in the tubers, and percentage of tubers with symptoms of nematode infection (dry and thick skins). The maximum values for the mean masses of commercial tubers were 2.5 and 1.9 kg with doses of 130 and 160 kg of N ha-1 from ammonium sulfate and urea, respectively. Doses of 130 and 154.3 kg of N ha-1 produced the maximum yields of commercial tubers of 19.7 and 14.9 t·ha-1 with ammonium sulfate and urea fertilization, respectively. The maximum levels of foliar N by using urea and ammonium sulfate were 36.5 and 29.3 g·kg-1, respectively, at a dosage of 250 kg·ha-1. The maximum starch contents of 25.7 and 28.3 % were obtained at doses of 114 and 116 kg of N ha-1 of ammonium sulfate and urea, respectively. The percentage of tubers infected with nematodes was 10% when the N source was urea and 15.6% when the source was ammonium sulfate, both at a dosage of 250 kg·ha-1.

Influência da cama de frango e de espaçamentos entre plantas na produtividade agroeconômica de mandioquinha-salsa

A cultura da mandioquinha-salsa constitui-se em ótima alternativa para pequenos e médios produtores, especialmente dentro dos conceitos de agricultura familiar. O objetivo deste trabalho foi conhecer a produtividade agroeconômica da mandioquinha-salsa cultivada com dois espaçamentos entre plantas (20 e 25 cm) e formas de adição de massa seca de cama de frango ao solo [cobertura (10 t ha-1), incorporada (10 t ha-1), cobertura (5 t ha-1) + incorporada (5 t ha-1) e sem cama de frango (0 t ha-1)], realizando duas colheitas independentes em diferentes estágios de maturação, 50% e 70% de senescência, que ocorreram respectivamente aos 224 e 249 dias após o plantio (DAP). As características avaliadas não foram influenciadas significativamente pela interação espaçamentos entre plantas e formas de adição de cama de frango, mas foram influenciadas pelas formas isoladas. As maiores massas de matérias frescas de folhas, coroas e os rebentos foram obtidos com o espaçamento de 25 cm entre plantas, nas duas colheitas. Aos 50% de senescência os aumentos foram de 27% (folhas), 28% (coroas) e 37% (rebentos) e aos 249 DAP foram de 25% (folhas), 13% (coroas), 18% (rebentos) e 22% (raízes comerciais) em relação a 20 cm entre plantas. Aos 70% de senescência as melhores produções de raízes comerciais foram com a cama de frango incorporada e em cobertura + incorporada, que superaram em 10,27 t ha-1 e 7,29 t ha-1, respectivamente, sem a cama de frango. Para serem obtidas maiores produtividades de raízes comerciais, o cultivo em canteiros da mandioquinha-salsa 'Amarela de Carandaí' deve ser feito com espaçamento de 25 cm entre plantas e com a adição ao solo de cama de frango na forma incorporada, realizando a colheita com 70% de senescência da parte foliar aos 249 DAP.