Diferenças estruturais foliares entre biótipos resistente e suscetível ao glyphosate de Digitaria insularis (L.) Fedde

We had, as an objective, characterizing, anatomically, the leaves of two populations of D. insularis (resistant biotype and susceptible biotype), which were collected in cropping areas in Paraná. In order to do this, a trial design in random sets was employed, which were repeated ten times. To obtain the data, it was evaluated the structural and quantitative variables of foliar blades of anatomical parts, which belonged to different leaves in the mature stage that were removed from distinct resistant and susceptible biotypes of D. insularis. The structural variables of the cross-sectional parts evaluated from the foliar blades were: the thickness of the foliar blade in the intercostal region (TBI); thickness of the keel (TK); stomata number (SN) and thickness of cuticle (TC) in the adaxial and abaxial faces. The resistant biotypes of D. insularis differ from the susceptible ones in several structural parameters, among them, there is the foliar blade in the interveinal region that was 7.3 ticker in the resistant biotype, which was also observed in the thickness of the keel, in the percentage of 11.3%, and in the thickness of the cuticle in the adaxial face (TCD), which was 53.8% thicker in the resistant biotype. In this way, we concluded that the anatomical foliar characteristics observed in the resistant biotypes, which differ from the susceptible ones, can be related to the reduction in the absorption and the herbicides translocation speed, constituting, therefore, possible mechanisms of resistance to glyphosateTivemos como objetivo caracterizar anatomicamente as folhas de duas populações de D. insularis (biótipo resistente e biótipo suscetível) coletadas em áreas agrícolas no Paraná. Para isso, utilizou-se delineamento experimental em blocos ao acaso, com dez repetições. Para a obtenção dos dados, foram avaliadas variáveis estruturais quantitativas de secções anatômicas da lâmina foliar, pertencentes a diferentes folhas no estágio maduro retiradas de distintos biótipos resistentes e suscetíveis de D. insularis. Entre as variáveis estruturais das secções transversais da lâmina foliar avaliadas foram: espessura da lâmina foliar na região intercostal (ELI); espessura da quilha (EQ); número de estômatos (NE); espessura da cutícula (EC) nas faces adaxial e abaxial. Os biótipos resistentes de D. insularis diferem dos susceptíveis em vários parâmetros estruturais, entre eles, quanto a lâmina foliar na região internervural que foi 7,3% mais espessa no biótipo resistente, o que também foi observado na espessura da quilha com 11,3% e na espessura da cutícula na face adaxial (ECD) que foi 53,8% mais espessa no resistente. Dessa forma, concluímos que as características anatômicas foliares observadas nos biótipos resistentes que diferem dos susceptíveis, podem estar relacionadas com a redução na absorção e na velocidade de translocação de herbicidas, constituindo assim possíveis mecanismos de resistência ao glyphosate

Weed interference in cassava in different cycles and cropping systems

The study aimed to determine the interference periods of weeds in cassava ‘IAC 90’ cultivated in different cycles and cropping systems. An experiment was conducted in the period 2014/15 (1st cycle) and another was conducted from the pruning of cassava plants in the period 2015/16 (2nd cycle). The experimental design was a randomized block design with split-split plots and four replicates. The plots represented the cropping systems (conventional and no-tillage) and the split-split plots corresponded to the periods with and without coexistence with weeds (0, 25, 50, 75, 100, 125, 150, 175, 200 and 225 days after planting or pruning - DAP/DAPr). In the 1st cycle, there was no interaction between the cropping systems and the coexistence periods and, therefore, based on the acceptable losses of 5% in the root and starch yield of 'IAC 90' cassava, the PCPI was estimated between 20 and 212 DAP and 14 to 214 DAP, respectively. In the 2nd cycle, the CPPWI ranged from 17 to 176 DAPr and 30 to 216 DAPr based on the root and starch yield obtained in the conventional method, respectively. While in no-tillage, the estimated CPPWI ranged from 18 to 198 DAPr and 9 to 218 DAPr based on root and starch yield, respectively. In general, the data indicate that conventional weed management should be carried out in a more intensified way than in no-tillage. In addition, CPPWI based on starch losses can avoid losses in root production

Interferência de plantas daninhas no acúmulo de nutrientes em folhas de mandioca sob plantio direto ou plantio convencional

The objective of this work was to evaluate the effect of weed competition on the accumulation of nitrogen and phosphorus in the leaves and on the dry weight of the roots of cassava (Manihot esculenta) in the conventional and no-tillage systems, in two crop cycles. The experiments were carried out in a randomized complete block design, with split-split plots and four replicates. The plots consisted of conventional tillage or no-tillage; the split plots, of the competition or not with weeds; and the split-split plots, of the evaluation periods (0, 25, 50, 75, 100, 125, 150, 175, 200, and 225 days after planting/pruning). In the first cycle, weed competition reduced the accumulation of nitrogen in 82.6 and 81.3% and of phosphorus in 65.7 and 85.3% under conventional tillage and no-tillage, respectively. In the second cycle, the reductions in the accumulation of nitrogen were of 41.1 and 52.4% and of phosphorus of 44.1 and 52.6%, in conventional tillage and no-tillage, respectively. The root dry weight of cassava grown with weed competition showed reductions of 15.8 and 11.2% under conventional tillage and no-tillage, respectively, only in the second cycle. Weed competition reduces the accumulation of nitrogen and phosphorus in the leaves of cassava in the conventional and no-tillage systems in both crop cycles, but reduces the dry matter of cassava roots only in the second cycle.O objetivo deste trabalho foi avaliar o efeito da competição de plantas daninhas sobre o acúmulo de nitrogênio e fósforo nas folhas e sobre a massa seca das raízes de mandioca (Manihot esculenta), nos sistemas convencional e direto, em dois ciclos de cultivo. Os experimentos foram realizados em delineamento de blocos ao acaso, com parcelas subsubdivididas e quatro repetições. As parcelas consistiram do plantio convencional ou do plantio direto; as subparcelas, da competição ou não com plantas daninhas; e as subsubparcelas, dos períodos de avaliação (0, 25, 50, 75, 100, 125, 150, 175, 200 e 225 dias após o plantio/poda). No primeiro ciclo, a competição com plantas daninhas reduziu o acúmulo de nitrogênio em 82,6 e 81,3% e o de fósforo em 65,7 e 85,3%, no plantio convencional e no plantio direto, respectivamente. No segundo ciclo, as reduções no acúmulo de nitrogênio foram de 41,1 e 52,4% e, no de fósforo, de 44,1 e 52,6%, no plantio convencional e no plantio direto, respectivamente. A massa seca das raízes de mandioca cultivada sob competição de plantas daninhas apresentou reduções de 15,8 e 11,2% no plantio convencional e no plantio direto, respectivamente, apenas no segundo ciclo. A competição de plantas daninhas reduz o acúmulo de nitrogênio e fósforo nas folhas de mandioca, nos sistemas convencional e plantio direto, em ambos os ciclos de cultivo, mas reduz a matéria seca das raízes de mandioca apenas no segundo ciclo

Períodos de convivência de plantas daninhas com cenoura cultivada com e sem palhada de aveia-preta

The objective of this work was to evaluate the effect of black oat (Avena strigosa) straw on the period prior to the interference (PPI) of weeds in the 'Alvorada' carrot (Daucus carota) crop. The experiment was carried out in a randomized complete block design, in a 2×5 factorial arrangement, with five replicates. The following two factors were evaluated in the 2016/2017 and 2017/2018 crop years: soil cover, with and without 10 Mg ha-1 black oat straw; and periods of coexistence with weeds – 0, 15, 30, 60, and 120 days after emergence (DAE). To determine the PPI, a loss of 5% in the commercial yield of carrot roots was considered as acceptable. At the end of the crop cycle, straw reduced the total dry mass of weeds by 43.5 and 67.5%, respectively, in the first and second crop years. The PPI of the crops with and without straw was, respectively, 2.0 and 1.5 DAE in the first crop year and 17 and 6.0 DAE in the second. The use of black oat straw increases the PPI for the 'Alvorada' carrot crop.O objetivo deste trabalho foi avaliar o efeito da palhada de aveia-preta (Avena strigosa) sobre o período anterior à interferência (PAI) de plantas daninhas na cultura da cenoura 'Alvorada' (Daucus carota). O experimento foi realizado em delineamento de blocos ao acaso, em arranjo fatorial 2×5, com cinco repetições. Os dois seguintes fatores foram avaliados nos anos de cultivo de 2016/2017 e 2017/2018: cobertura de solo com e sem 10 Mg ha-1 de palhada de aveia-preta; e períodos de coexistência com as plantas daninhas – 0, 15, 30, 60 e 120 dias após a emergência (DAE). Para determinar o PAI, considerou-se como aceitável a perda de 5% na produtividade comercial de raízes da cenoura. Ao final do ciclo da cultura, a palhada reduziu a massa seca total de plantas daninhas em 43,5 e 67,5%, respectivamente, no primeiro e no segundo ano de cultivo. O PAI dos cultivos com e sem palhada foi, respectivamente, de 2,0 e 1,5 DAE no primeiro ano e de 17 e 6,0 DAE no segundo. O uso da palhada de aveia-preta aumenta o PAI para cultura da cenoura 'Alvorada'

Fruit culture growth in Northeast Brazil and its relationship with work

Fruit growing in Brazil enhances regional development, as it generates income and absorbs local labor. The Brazilian Northeast presents ideal edaphoclimatic conditions for the development of several fruit trees, mainly in irrigated areas. The objective was to analyze the educational level and the relationship between the wages of men and women employed in the fruit sector in the Northeast region of Brazil. Thus, constituting historical series obtained from SIDRA-IBGE. The selected crops were coconut, mango and grape between the years 2001 to 2018; literacy rate and level of education in Brazil and the northeast region, the relationship between male and female genders, percentage of women in formal jobs in the years 2004 to 2015 and average monthly income in Brazil and the Northeast region and male and female genders in the years 2012 to 2015. There was a reduction in the area cultivated with coconut, however, in mango and grape cultures there was no increase in the area. Regarding the harvested area, the coconut-da-baia crop has a larger cultivated area, however, this area has been gradually reduced. In mango and grape crops, no variations were detected in the harvested areas. As for the average production, the grape crop has higher productivity. In the percentage of formal jobs, literacy and level of schooling of women both at national and regional level, there was a linear growth and higher than that of men, however there was a discrepancy in salary between genders even though women had a higher level of schooling.Fruit growing in Brazil enhances regional development, as it generates income and absorbs local labor. The Brazilian Northeast presents ideal edaphoclimatic conditions for the development of several fruit trees, mainly in irrigated areas. The objective was to analyze the educational level and the relationship between the wages of men and women employed in the fruit sector, in the Northeast region of Brazil. The selected crops were those of coconut, mango and grape, between the years 2001 to 2018; literacy rate and level of education in Brazil and the northeast region, the relationship between male and female genders, percentage of women in formal jobs in the years 2004 to 2015 and average monthly income in Brazil and the Northeast region and male and female genders in the years 2012 to 2015. There was a reduction in the area cultivated with coconut, however there was no increase in the area for mango and grape crops. Regarding the harvested area, the coconut crop showed a larger cultivated area, however, this area has been gradually reduced. In mango and grape crops, no variations were detected in the harvested areas. As for the average production, the grape crop has higher productivity. In the percentage of formal jobs, literacy and level of education of women, both nationally and regionally, there was a linear growth and higher than those of men. It is concluded that between men and women in the Northeast region, the salary difference was R$ 354.00, even with women with a higher educational level

Seletividade de herbicidas aplicados com óleo mineral na cultura da mandioca ‘Cascuda’

The use of adjuvant can influence the selectivity of herbicides on crops. Aimed to evaluate the selectivity of herbicides with different concentrations of mineral oil adjuvant in cassava 'Cascuda'. The experimental design was a randomized block design with four replications. We used a factorial design 3x3+1 which consisted of three herbicides clethodim (120 g ha-1), fluazifop-p-butyl (250 g ha-1) and mesotrione (240 g ha-1), three concentrations of mineral oil (Assist®) 0.0, 0.5 and 1.0% v v-1, and a control without application. All plots were kept free of weed interference by hand weeding. Only the mesotrione promoted phytointoxication mild to moderate (5.5 to 51.3%) when applied with mineral oil. However, all herbicides were selective for cassava plants 'Cascuda' in applied both in the presence and absence of mineral oil to 1% v v-1.O uso de adjuvante pode influenciar na seletividade dos herbicidas as culturas agrícolas. Objetivou-se avaliar a seletividade de herbicidas aplicados com diferentes concentrações de adjuvante óleo mineral na cultura da mandioca ‘Cascuda’. O delineamento experimental utilizado foi o de blocos ao acaso, com quatro repetições. Foi utilizado o esquema fatorial 3x3+1 que consistiu de três herbicidas clethodim (120 g ha-1); fluazifop-p-butyl (250 g ha-1) e mesotrione (240 g ha-1), três concentrações de óleo mineral (Assist®) 0,0; 0,5 e 1,0% v v-1; além de uma testemunha sem aplicação. Todas as parcelas foram mantidas livres da interferência das plantas daninhas por meio de capinas manuais. Apenas, o mesotrione promoveu sintomas de fitointoxicação leves a moderados (5,5 a 51,3%) quando aplicado com óleo mineral. Contudo, todos os herbicidas apresentaram-se seletivos à mandioca ‘Cascuda’ na dose aplicada, tanto na presença quanto ausência de óleo mineral até 1% v v-1

MANEJO DA MUCUNA-PRETA NA SUPRESSÃO DE PLANTAS DANINHAS NA CULTURA DA ALFACE-CRESPA

Plantas de cobertura podem causar a supressão de plantas daninhas devido aos efeitos físicos e alelopáticos produzidos pela palhada. O objetivo deste trabalho foi o de avaliar o manejo da palhada de mucuna-preta (superficial ou incorporada) no controle de plantas daninhas na cultura da alface-crespa. O delineamento experimental foi o de blocos ao acaso, dispostos em parcelas subdividas, com quatro repetições. As parcelas compreenderam os dois sistemas de manejo de palhada da mucuna-preta (superficial ou incorporada) e as subparcelas foram constituídas pela prática da capina manual (com ou sem capina). Os resultados reportaram que não houve redução na massa seca de plantas daninhas com o uso da palhada superficial ou incorporada. No entanto, o manejo com a palhada proporcionou aumento de 27% na área foliar e de 20% na massa seca na cultura da alface-crespa, além de ganhos de 32% na produtividade, quando utilizada de maneira incorporada ao solo e associada à prática da capina. Desta forma, concluiu-se que apesar do pouco efeito na supressão das plantas daninhas, o uso de palhada de mucuna-preta pode proporcionar maior produtividade para a cultura da alface-crespa, especialmente quando incorporada ao solo

Selectivity of residual herbicides and mixture with glyphosate applied after the pruning of cassava ‘Fécula Branca’

As variedades de mandioca (Manihot esculenta L. Crantz) destinadas para a indústria de fecularia geralmente são podadas no período de repouso fisiológico das plantas, sendo necessária a adoção de práticas de manejo das plantas daninhas para evitar a competição no segundo ciclo de desenvolvimento da cultura. Diante do exposto, o objetivo foi avaliar a seletividade de herbicidas pré-emergentes e da mistura destes com glyphosate em aplicações após a poda da mandioca 'Fécula Branca'. O delineamento experimental utilizado foi o de blocos ao acaso, com quatro repetições. Os tratamentos avaliados foram: glyphosate (720 g ha-1), carfentrazone (25 g ha-1), chlorimuron-ethyl (10 g ha-1), clomazone (1.080 g ha-1), flumioxazin (83 g ha-1), metribuzin (480 g ha-1) metsulfuron-methyl (2,4 g ha-1), glyphosate + carfentrazone (720 + 25 g ha-1), glyphosate + chlorimuron-ethyl (720 + 10 g ha-1), glyphosate + clomazone (720 + 1.080 g ha-1), glyphosate + flumioxazin (720 + 83 g ha-1), glyphosate + metribuzin (720 + 480 g ha-1), glyphosate + metsulfuron-methyl (720 + 2,4 g ha-1), além de uma testemunha sem aplicação. Avaliou-se a porcentagem de fitointoxicação, altura de planta, produtividade de raízes e o teor de fécula da mandioca.  Os herbicidas aplicados isolados e em mistura não causaram sintomas de fitointoxicação nas plantas de mandioca após a aplicação. Os herbicidas aplicados isolados e em mistura não reduziram a altura de planta, produtividade de raízes e o teor de fécula da mandioca em relação à testemunha sem aplicação. Conclui-se que a aplicação isolada dos herbicidas residuais e da mistura com glyphosate apresentaram-se seletivos, quando aplicados após a poda das plantas de mandioca 'Fécula Branca'.Cassava varieties (Manihot esculenta L. Crantz) intended for industrial starch manufacturers are usually pruned during the period of physiological rest of the plants, requiring the adoption of management practices to prevent weed competition in the second cycle of crop development. The objective was to evaluate the selectivity of pre-emergent herbicides applied alone or in tank mix with glyphosate in applications after pruning of cassava 'Fécula Branca'. The experimental design was a randomized block with four replications. The treatments were: glyphosate (720 g ha-1), carfentrazone (25 g ha-1), chlorimuron-ethyl  (10 g ha-1), clomazone (1,080 g ha-1), flumioxazin (83 g ha-1), metribuzin (480 g ha-1) metsulfuron-methyl  (2.4 g ha-1), glyphosate + carfentrazone (720 + 25 g ha-1), glyphosate + chlorimuron-ethyl  (720 + 10 g ha-1), glyphosate + clomazone (720 + 1080 g ha-1), glyphosate + flumioxazin (720 + 83 g ha-1), glyphosate + metribuzin (720 + 480 g ha-1), glyphosate + metsulfuron-methyl  (720 + 2.4 g ha-1), and an untreated control. Evaluations included percentage of phytotoxicity, plant height, root yield and starch content of cassava. The herbicides applied alone and in tank mix did not cause phytotoxicity in cassava plants after application. The herbicides applied alone and in tank mix did not reduce plant height, root yield and starch content of cassava compared to untreated control. The isolated application of residual herbicides and mixes with glyphosate were considered selective when applied after pruning of cassava plants 'Fécula Branca'

Método não destrutivo de estimativa da área foliar de plantas daninhas de ambiente aquático: tanner-grass e capim-fino

The continuous inputs from agriculture areas and human or industrial sewer have been provided a widely demographic explosion of tropical tanner-grass and para grasss plants in the rivers and water reservoirs of Brazil. Considering the importance of these noxious weeds there is a vast necessity of basic studies on aspects related to reproduction, growing, development, nutritional requirements, responses to control systems and others. In most studies, leaf area knowledge is crucial and it is one of the most difficult characteristics to be measured because it usually requires expensive equipments or it uses a destructive technique. The objective of this work was to develop equations for leaf blade dimensional parameters to allow determination of the leaf area of African tanner-grass (Brachiaria subquadripara (Trin.) Hitchc) and para grass (Brachiaria mutica (Forsk.) Stapf.). Correlations between real leaf area and dimensional parameters of leaf blade such as length along the main vein (L) and maximum width (W) perpendicular to the main axis were studied. Only the linear equations allowed a good leaf area estimate. It is suggested to opt for a simple linear equation involving respective products of length times maximum width considering linear coefficient equal to zero. Thus, B. subquadripara (SS) and B. mutica (SM) non destructive leaf blade area estimates may be performed by the following formulas: SS = 0.7719 (L x W) and SM = 0.7479 (L x W), with coefficients of determination (R(2)) of 0.9594 and 0.9408, respectively