Abstract: Sugarcane is an important Brazilian commodity, being usually cultivated in soils with low natural fertility. This study aimed to isolate diazotrophic endophytes from sugarcane tissues and evaluate the morphological and physiological characteristics of their colonies as well as their plant growth-promoting (PGP) traits in select diazotrophic endophytic bacteria. Fifty-six bacterial isolates were identified in the sugarcane tissues, and these isolates presented distinct morphological and physiological traits. A total of thirty-five bacterial isolates were biochemically evaluated. Overall, Bacillus was the dominant genus. Isolates of Methylobacterium spp. and Brevibacillus agri were present only in leaves, while Herbaspirillum seropedicae occurred only in stems. Except to IPA-CF45A, all isolates were nitrogenase positive. All endophytes exhibit production of indol 3-acetic acid. Over 50% of endophytes solubilize phosphate, release N-acyl homoserine lactones, and present the activity of 1-aminocyclopropane-1-carboxylic acid deaminase, catalase, lipase and protease. The network analysis showed that isolates belonged to Burkholderia, Herbaspirillum, and Methylobacterium interact with Bacillus. Bacterial endophytes exhibited distinct morphological, physiological, and PGP traits that are useful for sustainable agriculture, highlighting the isolates IPA-CC33, IPA-CF65, IPA-CC9 and IPA-CF27. Further studies on the effects of these diazotrophic endophytes and their potential for providing microbial inoculants for improving sugarcane fields will provide valuable information to maintain the sustainability and environment quality.

ABSTRACT Some forage species, such as pangolão grass (Digitaria eriantha Steud. cv. Survenola), are resilient in tropical semi arid regions. A possible reason for this is the presence of endophytic and rhizospheric microorganisms. Thus, this study evaluated the diversity of associative bacteria in pangolão grass. Bacteria associated with the roots, culm, leaves, and rhizospheric soil were isolated and characterized in three municipalities of Pernambuco, Brazil. An initial phenotypic characterization was followed by a genotypic assessment by based repetitive extragenic palindromic-polymerase chain reaction (BOX-PCR) and partial sequencing of the 16S rRNA gene. We obtained 325 phenotypically-characterized isolates grouped into 243 strains with 100% similarity by BOX-PCR. The most diverse sampling environment was Araripina, and all factors affected bacterial diversity. There were 135 groups with 90% similarity, that were represented by a single strain each for sequencing. Among the sequenced strains, 118 showed 96.84–99.9% similarity with previously described strains, whereas 17 could not be identified. The following 18 genera were identified from three phyla, five classes, seven orders, and 13 families: Achromobacter, Agrobacterium, Bacillus, Burkholderia, Curtobacterium, Enterobacter, Herbaspirillum, Kosakonia, Ochrobactrum, Paenibacillus, Pantoea, Priestia, Pseudomonas, Rhizobium, Serratia, Shinella, Stenotrophomonas, and Variovorax. The diversity of endophytic and rhizospheric bacteria may contribute to the resilience of pangolão, as various strains of these genera have been described as plant growth promoters. This is the first evaluation of pangolão bacterial diversity under tropical semi arid conditions. Since several of the genera include strains known to promote plant growth, we propose further research to evaluate this on crops.

Abstract: The growing need for the use of clean energy has led society to seek alternatives to fossil fuels in order to less pollute the environment. Sugarcane has been known to produce enough biomass and to have associative microorganisms, such as plant growth-promoting bacteria (PGPB), which have the potential to improve the yield of crops. The objective of this study is to evaluate the efficiency and the isotopic dilution of 15N of microbial inoculants containing endophytic diazotrophic bacteria, individually inoculated and in mixture, on productivity, technological quality and biological nitrogen fixation (BNF) of sugarcane variety RB92579. The experiment was conducted for three consecutive years, comprising different crop cycles, in a completely randomized block design with four replications. The evaluations were at 11 months after planting for plant-cane, and at 12 months after cutting for ratoon cane and second ratoon cane. The contribution of BNF by 15N natural abundance technique to inoculated treatments ranged from 18% to 57.31%. This study showed that no strain promoted the improvement on yield and biological nitrogen fixation during the three cycles of sugarcane (plant-cane, ratoon cane and second ratoon cane). However, industrial characteristics of sugar cane can be affectd by PGPB inoculation.

The use of microorganisms to improve the availability of nutrients to plants is of great importance to agriculture. This study aimed to evaluate the effect of triple inoculation of cowpea with arbuscular mycorrhizal fungi (AMF), plant growth-promoting bacteria (PGPB) and rhizobia to maximize biological nitrogen fixation (BNF) and promote plant growth. The experiment was conducted in a greenhouse using cowpea plants (Vigna unguiculata L. Walp cv. IPA 206). The treatments included inoculation with strains of Bradyrhizobium sp. (BR 3267 and EI - 6) individually and as a mixture, an absolute control (AC) and mineral nitrogen control (NC), all combined with the presence or absence of native AMF (Glomus etunicatum) and PGPB (Paenibacillus brasilensis - 24) in a 5x2x2 factorial design. All treatments were replicated three times. Contrasts were performed to study the treatment of variables. Inoculation with Bradyrhizobium sp. (BR 3267 and EI - 6) and G. etunicatum favored nitrogen acquisition and phosphorus availability for the cowpea plants. Inoculation with P. brasilensis - 24 increased colonization by Bradyrhizobium sp. and G. etunicatum and promoted cowpea growth, while the nitrogen from symbiosis was sufficient to supply the plants nutritional needs.

A ocorrência de fungos micorrízicos arbusculares (FMAs) foi investigada em áreas cultivadas com leucena (Leucaena leucocephala L.) e sabiá (Mimosa caesalpiniaefolia Benth), no Estado de Pernambuco. Amostras de solo foram coletadas em cinco estações experimentais da Empresa Pernambucana de Pesquisa Agropecuária (IPA), nas cidades de Arcoverde, com plantio de leucena (AL) e sabiá (AS); Caruaru, com plantio de leucena (CL); e Itambé (IS), São Bento do Una (SBS) e Serra Talhada (STS), com plantio de sabiá. O número de esporos variou de 69 (STS) a 437/50 g de solo (CL) e a colonização micorrízica, de 11 (CL) a 64% (IS). Nas áreas com plantio de leucena, a colonização foi inferior a 15%, enquanto naquelas com cultivo de sábia houve variação de 36 a 64%. Foram observadas 24 espécies de FMAs, pertencentes aos gêneros: Acaulospora (6), Archaeospora (1), Entrophospora (1), Gigaspora (3), Glomus (6), Paraglomus (1) e Scutellospora (6). As áreas CL e STS foram as que apresentaram maior número de espécies (14). Acaulospora scrobiculata, Archaeospora leptoticha e Glomus etunicatum foram encontradas em todas as áreas.

The occurrence of arbuscular mycorrhizal fungi (AMF) in plantations of Leucaena leucocephala L. (leucaena) and Mimosa caesalpiniaefolia Benth (sabia) in the State of Pernambuco was investigated. Soil samples were collected in five research centers of the Agricultural Research Institute of Pernambuco (IPA), in the cities of Arcoverde - plantation of leucaena (AL) and sabiá (AS); Caruaru (CL) - leucaena plantation; Itambé (IS), São Bento do Una (SBS) and Serra Talhada (STS) - plantation of sabiá. Mycorrhizal spores were extracted from soil, with the highest number (437/50g of soil) being found in the CL region and the lowest (69/50g of soil) in the STS region. The mycorrhizal colonization ranged from 11% (CL) to 64% (IS). The colonization was inferior to 15% in areas of leucaena plantation, however, in areas of sabiá, it ranged from 36% to 64%. Twenty-four AMF species were identified in the genus: Acaulospora (6), Archaeospora (1), Entrophospora (1), Gigaspora (3), Glomus (6), Paraglomus (1) and Scutellospora (6). The highest species number was recorded in the CL and STS regions (14). Acaulospora scrobiculata, Archaeospora leptoticha and Glomus etunicatum were found in all regions.

Foi avaliado o efeito da mineração gesseira sobre os fungos micorrízicos arbusculares (FMA). Amostras de solo (10/área) foram coletadas em quatro áreas de uma mineradora: caatinga nativa (CN), arredores da mina (AM), rejeito (R) e interface entre o rejeito e caatinga degradada (IN), nos períodos chuvoso (dezembro/2003) e seco (setembro/2004). Foram registradas 42 espécies de fanerógamas: 25 na CN, 14 nos AM, 10 na IN e cinco na R. A CN apresentou maior número de espécies vegetais, esporos e propágulos infectivos de FMA. Número de esporos e colonização radicular diferiram entre os períodos. Maior esporulação ocorreu no período chuvoso, o número mais provável (NMP) de propágulos e colonização foram maiores no seco. Houve correlação positiva entre NMP e esporos nos dois períodos. No período chuvoso, o NMP foi negativamente correlacionado com colonização. Esta foi maior nas áreas AM e R. A atividade mineradora diminuiu a diversidade vegetal, o NMP de propágulos e a quantidade de esporos em relação à caatinga nativa.

The effect of gypsum mining on arbuscular mycorrhizal fungi (AMF) was evaluated. Soil samples (10/area) were collected in four areas of a mine: native "caatinga" (CN); mine surroundings (AM); waste deposit (R) and interface between waste deposit and degraded caatinga (IN), in two periods, raining (December/2003) and dry (September/2004). Fourty two phanerogam species were registered: 25 at CN, 14 at AM, 10 at IN, and 5 at R. The CN presented higher number of plant species, spores and infectives propagules (most probable number-MPN) of AMF. Number of spores and root colonization differed between the periods. Higher sporulation occurred in the raining season, MPN of propagules and colonization were higher in the dry season. Positive correlation occurred between MPN and spores in both periods. In the raining season, MPN was negatively correlated with colonization. That was higher in the AM and R areas. The mining activity decreased plant diversity, MPN of propagules and amount of AMF spores in relation to the native caatinga.

Este artigo trata do problema de performance <IMG SRC="http:/img/fbpe/ca/v13n1/a03img02.gif"><FONT FACE=Symbol>¥</FONT> para sistemas LPV. O critério de performance <IMG SRC="http:/img/fbpe/ca/v13n1/a03img02.gif"><FONT FACE=Symbol>¥</FONT> é obtido empregando-se uma função de Lyapunov com dependência quadrática nos parâmetros do sistema. O critério de performance usado admite que os parâmetros do sistema e suas respectivas taxas de variação sejam confinadas numa região convexa. Sob estas considerações obtém-se LMIs que apresentam condições suficientes destinadas aos casos de análise e síntese de sistemas LPV onde um critério de performance <IMG SRC="http:/img/fbpe/ca/v13n1/a03img02.gif"><FONT FACE=Symbol>¥</FONT> é otimizado.

This paper deals with the problem of <IMG SRC="http:/img/fbpe/ca/v13n1/a03img02.gif"><FONT FACE=Symbol>¥</FONT> performance for LPV systems. The <IMG SRC="http:/img/fbpe/ca/v13n1/a03img02.gif"><FONT FACE=Symbol>¥</FONT> performance index is based on a parameter dependent Lyapunov function with quadratic dependence on the parameters as well as on the system state. This stability notion is appropriate to deal with real parameters with magnitude and rate of change which are confined to a given convex region. Sufficient conditions based on LMI are developed for the <IMG SRC="http:/img/fbpe/ca/v13n1/a03img02.gif"><FONT FACE=Symbol>¥</FONT> performance analysis of LPV systems and designs of LPV controllers with guaranteed <IMG SRC="http:/img/fbpe/ca/v13n1/a03img02.gif"><FONT FACE=Symbol>¥</FONT> performance.

O objetivo deste trabalho foi comparar a idade ao primeiro parto (IPP) e o peso ao parto (PVP) de vacas da raça Nelore e cruzadas 1/4 Charolês + 3/4 Nelore (1CHA3NEL) e 5/8 Charolês + 3/8 Nelore (5CHA3NEL) e as relações peso do bezerro ao nascimento/PVP (RPN) e peso do bezerro à desmama aos 270 dias/PVP (RPD) de bezerros nelores, 1CHA3NEL, 5CHA3NEL, canchins e 7/16 Charolês + 9/16 Nelore (7CHA9NEL). Análises de variância foram realizadas pelo método dos quadrados mínimos, usando-se modelos matemáticos que incluíram efeitos de ano e época de nascimento e grupo genético da vaca para IPP; ano, época e número do parto e grupo genético da vaca para PVP; e ano, época e número do parto, sexo e grupo genético do bezerro para RPN e RPD. O grupo genético influenciou as características estudadas. As médias estimadas de IPP e PVP foram iguais a 1073,0 ± 9,0 dias e 425,4 ± 1,4 kg para as vacas nelores, 1043,5 ± 3,6 dias e 447,4 ± 1,7 kg para as vacas 1CHA3NEL e 966,1 ± 5,2 dias e 486,4 ± 2,7 kg para as vacas 5CHA3NEL, respectivamente. As médias estimadas de RPN e RPD foram iguais a 66,5 ± 0,9 e 438,3 ± 6,2 g/kg para os bezerros Nelore, 69,6 ± 0,4 e 451,4 ± 2,5 g/kg para os bezerros 1CHA3NEL, 75,1 ± 0,5 e 515,9 ± 3,3 g/kg para os bezerros 5CHA3NEL, 72,6 ± 0,7 e 469,0 ± 4,9 g/kg para os bezerros Canchim e 73,9 ± 0,8 e 501,8 ± 5,8 g/kg para os bezerros 7CHA9NEL, respectivamente. Os efeitos aditivo direto da raça Charolesa, como desvio da raça Nelore, e heterótico individual entre as raças Charolesa e Nelore foram iguais a -138,40 ± 23,24 e -73,89 ± 24,34 dias para IPP e 112,3 ± 11,40 e -12,23 ± 9,08 kg para PVP, respectivamente. Os efeitos aditivos direto e materno e heteróticos individual e materno foram iguais a 0,6 ± 9,0; -11,1 ± 4,9; 5,9 ± 5,6; e 13,1 ± 3,9 g/kg para RPN e 94,3 ± 66,4; -277,0 ± 32,8; -19,0 ± 39,9; e 206,4 ± 29,6 g/kg para RPD, respectivamente. Os resultados indicam que, quanto maior a porcentagem de genes de Charolês na vaca, menor sua IPP, maior seu PVP e menores as RPN e RPD e, quanto maior a porcentagem esperada de heterozigose na vaca, menor sua IPP e maiores as relações RPN e RPD.

The objective of this study was to compare age at first calving (AFC) and cow weight at calving (CWC) of straightbred Nellore and crossbred 1/4 Charolais + 3/4 Nellore (1CHA3NEL), and 5/8 Charolais + 3/8 Nellore (5CHA3NEL) cows, and birth weight of calf/CWC (BWR) and weaning weight of calf at 270 days/CWC (WWR) ratios of straightbred Nellore and crossbred 1CHA3NEL, 5CHA3NEL, Canchim (5/8 Charolais + 3/8 Nellore) and 7/16 Charolais + 9/16 Nellore (7CHA9NEL) calves. Analyses of variance were carried out by the least squares method, with models that included the effects of year and season of birth, and genetic group of cow for AFC; year, season, and age of cow at calving, and genetic group of cow for CWC; and year, season, and age of cow at calving, and sex and genetic group of calf for BWR and WWR. Genetic group affected all studied traits. The least squares means for AFC and CWC were 1073.0 ± 9.0 days and 425.4 ± 1.4 kg for the Nellore, 1043.5 ± 3.6 days and 447.4 ± 1.7 kg for the 1CHA3NEL, and 966.1 ± 5.2 days and 486.4 ± 2.7 kg for the 5CHA3NEL cows, respectively. The least squares means for BWR and WWR were 66.5 ± 0.9 and 438.3 ± 6.2 g/kg for the Nellore, 69.6 ± 0.4 and 415.4 ± 2.5 g/kg for the 1CHA3NEL, 75.1 ± 0.5 and 515.9 ± 3.3 g/kg for the 5CHA3NEL, 72.6 ± 0.7 and 469.0 ± 4.9 g/kg for the Canchim, and 73.9 ± 0.8 and 501.8 ± 5.8 g/kg for the 7CHA9NEL calves, respectively. The additive direct effect of the Charolais, as a deviation of the Nellore, and the heterotic individual effect of the Charolais and Nellore breeds were -138.40 ± 23.24 and -73.89 ± 24.34 days for AFC, and 112.30 ± 11.40 and -12.23 ± 9.08 kg for CWC, respectively. The additive direct, additive maternal, heterotic individual and heterotic maternal effects were 0.6 ± 9.0, -11.1 ± 4.9, 5.9 ± 5.6, and 13.1 ± 3.9 g/kg for BWR and 94.3 ± 66.4, -277.0 ± 32.8, -19.0 ± 39.9, and 206.4 ± 29.6 g/kg for WWR, respectively. The results show that as higher was the percentage of cows Charolais genes, the smaller its AFC, the higher its CWC, and the smaller the BWR and WWR ratios; and the as higher the expected heterozygosity in the cow, the smaller its AFC, and the higher the BWR and WWR.