Edvaldo Sagrilo

Decomposição e liberação de nutrientes de resíduos vegetais depositados sobre Latossolo Amarelo no Cerrado Maranhense

In the no-tillage system the use of cover crops is a widely adopted alternative to increase the sustainability of the agricultural system. This study aimed to evaluate the decomposition rate and total nitrogen (N), phosphorus (P) and potassium (K) release from the biomass of natural bush fallow and cover crops (Brachiaria sp., millet and Brachiaria sp. + millet intercrop), cultivated on a Yellow Latosol in the savanna of the Maranhao State. The experiment was carried out under no-tillage system after maize harvesting. Dry matter production, decomposition rate and nutrient release (N, P and K) at twenty-day intervals, until one hundred days after biomass cutting were evaluated. Millet or Brachiaria sp. mono or intercropped and natural bush fallow showed similar decreases in their decomposition in the first sixty days, with losses of 10; 13; 16 e 12% respectively. The highest and lowest rate of N release was observed on millet and Brachiaria sp. + millet intercrop, respectively. Among the nutrients, K was the earliest released in all treatments. The Braquiaria sp. is the cover crop with greater resistance to decompose, keeping the residue on the soil for longer periods in the Cerrado of Maranhao State.

Interação genótipo x ambiente em genótipos de feijão-caupi semiprostrado via modelos mistos

The mixed model methodology (REML / BLUP) has been used to study the effects of genotype x environment interaction (G x E) in various crops, such as: rice, common bean, cane sugar, cashew and eucalyptus, but still was not applied in cowpea. The aim of this work was to select simultaneously semiprostrade cowpea genotypes grown in the state of Mato Grosso do Sul, via mixed models, bringing together high adaptability, stability and yield grain. It were conducted four growing amount of trials and use of genotypes of cowpea genotypes in 2005 and 2006 in Aquidauana, Chapadao do Sul and Dourados. The experimental design was a randomized complete blocks with four replications and 20 genotypes. The genetic parameters were estimated by REML/BLUP methodology and, the selection was based on the MHPRVG method (harmonic mean of the relative performance of genetic values) in three strategies: selection based on predicted breeding value, having considered the performance mean of genotypes in all environments (no interaction effect) or performance in each environment (with interaction effect); and simultaneous selection for grain yield, stability and adaptability. BRS Paraguacu, MNC99-542F-5 and MNC99-508G-1 genotypes can be grown in various environments, as they bring together high grain yield, adaptability and stability. The heritability of the average of genotypes found indicates moderate to high, a fact which indicates excellent possibilities for selection, allowing selective accuracy of 82%.

LEGUMES AND FORAGE SPECIES SOLE OR INTERCROPPED WITH CORN IN SOYBEAN-CORN SUCCESSION IN MIDWESTERN BRAZIL

The feasibility of no-tillage in the Cerrado (Savanna-like vegetation of Brazil) depends on the production of sufficient above-ground crop residue, which can be increased by corn-forage intercropping. This study evaluated how above-ground crop residue production and yields of soybean and late-season corn in a soybean-corn rotation were influenced by the following crops in the year before soybean: corn (Zea mays L.) intercropped with Brachiaria (Urochloa) brizantha cv. Marandu, B. decumbens cv. Basilisk, B. ruziziensis, cv. comum., Panicummaximum cv. Tanzânia, sunn hemp (Crotalaria juncea L.), pigeon pea [Cajanus cajan (L.) Millsp]; sole corn, forage sorghum [Sorghum bicolor (L.) Moench (cv. Santa Elisa)], and ruzi grass. In March 2005, corn and forage species were planted in alternate rows spaced 0.90 m apart, and sole forage species were planted in rows spaced 0.45 m apart. In October 2005, the forages were killed with glyphosate and soybean was planted. After the soybean harvest in March 2006, sole late-season corn was planted in the entire experimental area. Corn grain and stover yields were unaffected by intercropping. Above-ground crop residue was greater when corn was intercropped with Tanzania grass (10.7 Mg ha-1), Marandu (10.1 Mg ha-1), and Ruzi Grass (9.8 Mg ha-1) than when corn was not intercropped (4.0 Mg ha-1). The intercropped treatments increased the percentage of soil surface covered with crop residue. Soybean and corn grain yields were higher after sole ruzi grass and intercropped ruzi grass than after other crops. The intercropping corn with Brachiaria spp. and corn with Panicum spp. increases above-ground crop residue production and maintains nutrients in the soil without reducing late-season corn yield and the viability of no-till in the midwestern region of Brazil.

Comparison of methods for phenotypic stability analysis of cassava (Manihot esculenta Crantz) genotypes for yield and storage root dry matter content

O objetivo deste trabalho foi comparar diferentes metodologias de analise de estabilidade fenotipica considerando producao e teor de materia seca nas raizes tuberosas de oito genotipos de mandioca, avaliados em oito ambientes na regiao Noroeste do Parana. Todas as metodologias aplicadas se mostraram aptas no estudo da estabilidade dos genotipos avaliados, cada uma delas com suas particularidades. As metodologias de Eskridge, Annicchiarico e Lin e Binns se mostraram mais adequadas para situacoes de menor efeito da interacao G x A. A analise AMMI e a metodologia de Toler e Burrows propiciaram um melhor detalhamento das adaptacoes especificas dos genotipos a ambientes favoraveis e desaforaveis. E sugerido o uso simultâneo da analise AMMI e da metodologia de Toler e Burrows. O clone IAC 190-89 mostrou-se mais promissor.

Effect of harvest period on the quality of storage roots and protein content of the leaves in five cassava cultivars (Manihot esculenta, Crantz)

The effect of harvest period on the quality of storage roots and leaves of cassava cultivars was determined in an experiment carried out in a randomized complete block design with four replications in a split plot scheme, with five cultivars in the plots and ten harvest times in the subplots. The IAC 13 cultivar had the highest rate of dry matter accumulation in the storage roots and the Mico cultivar the lowest. The period of least dry matter content in the storage roots occurred later for the Fecula Branca, Mico and IAC 14 cultivars, and the minimum starch content in the storage roots occurred later for the Fecula Branca and Mico cultivars. In general, the IAC 13, IAC 14 and Fecula Branca cultivars had higher dry matter content in the storage roots, while higher starch content in the dry and fresh matter were obtained in the Fecula Branca cultivar. The crude protein content in the leaves decreased as the plant aged.

Efeito da época de colheita no crescimento vegetativo, na produtividade e na qualidade de raízes de três cultivares de mandioca

With the objective of determining the effect of harvesting time in the vegetative growth, yield and quality of storage roots of three cassava cultivars (Manihot esculenta Crantz), an experiment was carried out in an area of red distrophic Red Latosol in Araruna, Northwest of Parana state, from October, 1997 to May, 1999. The experimental design was a randomized complete blocks with four replications and treatments arranged in split plots. The main treatments were the cassava cultivars Mico, IAC 13 and IAC 14 and the secondary treatments were ten monthly harvests starting from the second plant growing season. The canopy yield observed in the second season, presented an increase of 50.0%. The good development of the vegetative structure of the plants resulted in a greater accumulation of reserve material in the storage roots, increasing its yield. The highest harvest indices were observed from 19 to 21 months, with mean values superior to 54.0%. The cultivars were not significantly different in production of tuberous roots, dry matter and starch. The second phase of physiologic rest of the plants showed to be more favourable for harvesting, expressed in terms of production of storage roots (92.5%), of dry matter (125.0%) and starch (144.0%).

Dry matter production and distribution in three cassava (Manihot esculenta Crantz) cultivars during the second vegetative plant cycle

A study was carried out in Araruna County, State of Parana, to understand the relationship between the total dry matter yield and its proportion allocated to the storage roots of cassava (Manihot esculenta Crantz) plants in the second vegetative cycle. The experimental design was a randomized complete block in split-plot scheme with four replications. The plots consisted of the Mico, IAC 13 and IAC 14 cultivars and the monthly harvesting dates were assessed in the sub-plots. The results showed that the Mico and IAC 13 cultivars were more efficient in allocating dry matter to the storage roots. The IAC 14 cultivar allocated a higher proportion of assimilates to stems compared with the other two cultivars. With regard to the influence of harvesting time, the lowest harvest indexes were observed in the periods of more intense vegetative growth. However, the highest carbohydrate proportions were allocated to the storage roots during periods of low vegetative growth.

Effect of harvest period on foliage production and dry matter distribution in five cassava cultivars during the second plant cycle

The objective of this work was to study the leaf production pattern and dry matter distribution in cassava during the second plant cycle. The completely randomized experimental design with four replications was used, with five cultivars in the main plots and ten harvest times in the sub-plots. Foliage production was affected by plant age, being higher in hot periods. Leaf blades and petioles dry matter content presented a linear increase due to a progressive decrease in the amount of young leaves and ontogenetic factors. The stems provided, temporarily, carbohydrates to the plant re-growth, delaying the availability and use of storage roots dry matter. The dry matter content in the storage roots was lower during the vegetative and higher during rest period. The storage roots diameter increased considerably when the amount of leaves was higher, indicating the importance of leaf area in the cassava plant production.

Redes neurais artificiais para identificar genótipos de feijão‑caupi semiprostrado com alta adaptabilidade e estabilidade fenotípicas

O objetivo deste trabalho foi verificar a concordância entre as redes neurais artificiais (RNAs) e o metodo de Eberhart & Russel na identificacao de genotipos de feijao-caupi (Vigna unguiculata) com alta adaptabilidade e estabilidade fenotipicas. Utilizou-se o delineamento experimental de blocos ao acaso com quatro repeticoes. Os tratamentos consistiram de 18 linhagens experimentais e duas cultivares de feijao-caupi. Foram conduzidos quatro ensaios de valor de cultivo e uso nos municipios de Aquidauana, Chapadao do Sul e Dourados, no estado do Mato Grosso do Sul. Os dados de produtividade de graos foram submetidos as analises de variância individual e conjunta. Em seguida, os dados foram submetidos as analises de adaptabilidade e estabilidade por meio dos metodos de Eberhart & Russell e de RNAs. Houve elevada concordância entre os metodos avaliados quanto a discriminacao da adaptabilidade fenotipica dos genotipos de feijao-caupi semiprostrado, o que indica que as RNAs podem ser utilizadas em programas de melhoramento genetico. Em ambos os metodos avaliados, os genotipos BRS Xiquexique, TE97-304G-12 e MNC99-542F-5 sao recomendados para ambientes desfavoraveis, gerais e favoraveis, respectivamente, por apresentarem produtividade de graos acima da media geral dos ambientes e alta estabilidade fenotipica.

Performance de cultivares de mandioca e incidência de mosca branca no Vale do Ivinhema, Mato Grosso do Sul

The Ivinhema Valley is the most important region for cassava production in State of Mato Grosso do Sul. However, the restricted number of cultivars available for this region contributes for the occurrence of low yields and increasing diseases and pests. The objective of this study was to evaluate the performance of cassava genotypes in the region of Ivinhema Valley. The experiments were conducted from July/2005 to September/2006, in Nova Andradina, Ivinhema and Deodapolis in a randomized complete block design, with four replications. Yield components and resistance to sooty mould caused by whiteflies (Bemisia sp.) were evaluated in 11 cassava cultivars. It was found that the cultivars IAC 12 and Fecula Branca were the most resistant to sooty mould incidence. Cv. Cascuda showed the largest yield of storage roots and dry matter in all tested environments.