F. M. Lamas

Comparação de métodos para avaliar a adaptabilidade e estabilidade produtiva em algodoeiro

The objective of this work was to compare different methods used to estimate adaptability and stability of 17 cotton genotypes evaluated in 23 locations of the Brazilian savannah. Genotype and environment effects and genotype x environment interaction were significant. According to ecovalence and AMMI models, cultivar BRS Cedro showed the best stability. Varieties Delta Penta and BRS Ipe were among the most unstable genotypes, but not among the most productive. Using the methods of Eberhart & Russel, Lin & Binns and Annicchiarico, genotypes BRS 269 - Buriti, FMT 701 and CNPA GO 2001-999 were the most stable and among the five most productive on average. The evaluation of the specific adaptabilities provided by the AMMI analysis is of great importance in the study of the behavior of genotypes. The amount of information generated and the facilities of interpretation favors Lin & Binns method, which can be complemented by an AMMI analysis.

Reações do algodoeiro CNPA-ITA 90 ao cloreto de mepiquat

The effects of different doses of mepiquat chloride on cotton ( Gossypium hirsutum L.) plants, cultivar CNPA-ITA 90, during the 1993/94 and 1994/95 growing seasons were evaluated at Itamarati farm, Ponta Pora, MS, Brazil. The doses were split in three application dates and the experi- mental design was in randomized blocks, with five treatments replicated four times. The treatments were as follows: 1) unsprayed control; 2) 12.5+12.5+25.0 (50.0); 3) 25.0+25.0+25.0 (75.0); 4) 0.0+50.0+50.0 (100.0); and 5) 12.5+62.5+50.0 (125.0) g ha -1 of mepiquat chloride. The spraying was done at 34, 47 and 62 days after emergence (DAE) in 1993/94 and at 42, 60 and 73 DAE in 1994/95, when the plants were at the average hight of 51, 84 and 93 cm and 61, 79 and 97 cm, respectively. Increasing dose of mepiquat chloride caused decreasing in plant height; leaf stems and total above ground dry matter; number of nodes and branching; the branches length; the number of dam- aged fruits; the total number of bolls and the number of fully opened bolls.

Aplicação seqüencial de cloreto de mepiquat em algodoeiro

Com o objetivo de avaliar o efeito de doses de cloreto de mepiquat aplicadas de forma parcelada, foi conduzido, em Jaboticabal, SP, um experimento com a cultivar de algodoeiro IAC 22. O delineamento experimental foi o de blocos casualizados, com 13 tratamentos e 4 repeticoes. O efeito do cloreto de mepiquat sobre a reducao da altura das plantas foi mais evidenciado pela dose total aplicada do que pelo uso do esquema de parcelamento. A menor dose estudada (55 g/ha) foi suficiente para que as plantas, por ocasiao da colheita, estivessem com altura inferior a 1,30 m. O cloreto de mepiquat proporcionou reducao no comprimento dos ramos e um melhor equilibrio entre as partes reprodutiva e vegetativa. As caracteristicas peso de capulho, peso de 100 sementes, porcentagem de fibra e producao de algodao em caroco, nao foram significativamente afetadas pelos tratamentos.

BRS 336: a high-quality fiber upland cotton cultivar for Brazilian savanna and semi-arid conditions

Cotton cultivar BRS 336 is a high-quality fiber upland cultivar and has wide adaptation to the Brazilian growing areas, with resistance to bacterial blight. BRS 336 exhibited fiber length higher than 32.0 mm in all field tests. Also, fiber strength exceeded all upland cotton currently grown in Brazil.

Efeito do cloreto de mepiquat e do thidiazuron sobre algumas características das sementes do algodoeiro

Com o objetivo de avaliar o efeito de diferentes doses de cloreto de mepiquat (0, 50, 75, 100 e 125 g/ha) e de thidiazuron (0, 45, 60 e 75 g/ha) sobre as caracteristicas fisiologicas de sementes de algodoeiro, foi conduzido, na UNESP, Jaboticabal, SP, um experimento inteiramente casualizado, num arranjo fatorial (5x4), com quatro repeticoes. Com o aumento da dose de cloreto de mepiquat, verificou-se aumento do peso de 100 sementes e do indice de velocidade de emergencia de plântulas. O efeito do cloreto de mepiquat e do thidiazuron sobre a materia seca das plântulas foi antagonico. A porcentagem de germinacao e o comprimento do hipocotilo nao foram significativamente afetados pelo cloreto de mepiquat, pelo thidiazuron e pela interacao entre eles.

Espécies vegetais para cobertura do solo: influência sobre plantas daninhas e a produtividade do algodoeiro em sistema plantio direto

Este trabalho objetivou avaliar a producao, a persistencia e os efeitos de coberturas vegetais sobre as plantas daninhas e a produtividade do algodoeiro em sistema plantio direto. Os tratamentos consistiram das especies de cobertura: milheto (Pennisetum glaucum (L.) R. Brown), Brachiaria ruziziensis Germain & Evrard, sorgo forrageiro (Sorghum bicolor L. Moench), capim-pe-de-galinha (Eleusine coracana L. Gaerth), Crotalaria juncea L., Crotalaria spectabilis Roth, aveia-preta (Avena strigosa Schreb.), nabo forrageiro (Raphanus sativus L.), P. glaucum + C. juncea, P. glaucum + C. spectabilis, B. ruziziensis + C. juncea, B. ruziziensis + C. spectabilis, S. bicolor + C. juncea, S. bicolor + C. spectabilis, E. coracana + C. juncea, E. coracana + C. spectabilis, A. strigosa + R. sativus, P. glaucum + R. sativus e pousio. As especies foram semeadas no final do verao, apos a colheita de soja, e o algodoeiro BRS 269-Buriti, nove meses apos. O delineamento experimental foi em blocos ao acaso, com quatro repeticoes. As especies B. ruziziensis, B. ruziziensis + C. juncea, B. ruziziensis + C. spectabilis e P. glaucum + R. sativus produziram mais de 6,8 t ha-1 de biomassa seca. A palhada produzida pela B. ruziziensis garantiu boa cobertura do solo durante o ciclo do algodoeiro. A biomassa seca de B. ruziziensis, B. ruziziensis + C. juncea e B. ruziziensis + C. spectabilis reduziu a infestacao de plantas daninhas ate a epoca de semeadura do algodao e durante os estadios iniciais de seu desenvolvimento. Palhas de R. sativus e A. strigosa, solteiras e consorciadas, interferiram negativamente na produtividade do algodoeiro.

Cloreto de mepiquat, thidiazuron e ethephon aplicados no algodoeiro em Ponta Porã, MS

The objective of this study was to evaluate the effect of doses of mepiquat chloride, thidiazuron and ethephon on cotton (Gossypium hirsutum L.), applied in parcels, and were surveyed in Itamarati Farm at Ponta Pora county. The mepiquat chloride doses were: (0.0; 12.5 + 12.5 + 25.0 = 50.0; 25.0 + 25.0 + 25.0 = 75.0; 0.0 + 50.0 + 50.0 = 100.0; 12.5 + 62.5 + 50.0 = 125.0) g ha-1. The applications were made at 34, 47 and 63 days after emergence(DAE) in 1993/94 and at 42, 60 and 73 DAE in 1994/95. Thidiazuron was applied when 70% of bolls were opened at the doses 0.0, 45.0, 60.0 and 75.0 g ha-1. Ethephon was applied seven days after thidiazuron, when 85% defoliation was observed, in the doses of 0.0, 960.0 and 1,440.0 g ha-1. The experimental design used was strips with subdivided subparcelas. Mepiquat chloride decrease the number of unripe fruits, increased the weight of 100 seeds and the boll average weight. The defoliation percentage enhanced with increasing thidiazuron and ethephon doses. Mepiquat chloride x thidiazuron x ethephon interaction was significative to the percentage of opening bolls and production of cotton seed.

Occurrence of Target Spot, caused by Corynespora cassiicola, on cotton plants in Dourados, Mato Grosso do Sul State

Target spot or Corynespora leaf blight is a traditional soybean disease caused by Corynespora cassiicola (Berk & Curt.) Wei. This disease was first reported on soybean in Brazil in 1974. The fungus has been found in almost all soybean growing regions in Brazil, causing economic losses. C. cassiicola survives on crop residues and infected seeds, which are the main way of spread. The fungus is capable of infecting a large number of crop plants (Soares, R. M; Godoy, C. V; Oliveira, M. C. N. de. Escala diagramática para avaliação da severidade da mancha alvo da soja. Trop. plant pathol.[online]. 2009, vol.34, n.5). On cotton, this disease was first reported in the state of Mato Grosso, Brazil, in 1995 (Mehta, Y.R., Motomura, K.F. and Almeida, W.P. Corynespora Leaf Spot of Cotton in Brasil. Fitopatologia Brasileira, 30, 131. 2005). In