The genus Gossypium is composed of both diploid and allotetraploid species. The five allotetraploid species of Gossypium are sexually compatible, and only partial sexual barriers have been described. Natural hybrids among them do not occur or occur in situ with very low frequency in Brazil in the rare places where cultivated upland cotton ( Gossypium hirsutum L.) occurs in a sympatric range with Gossypium barbadense L. or Gossypium mustelinum Miers. We evaluated the presence of pollen competition as a prezygotic barrier in crosses between upland cotton and G. barbadense and G. mustelinum. We found that G. barbadense pollinated with a mixture of 50% upland cotton and 50% G. barbadense pollen resulted in 17.4%–31.1% interspecific hybrids, depending upon the upland cotton genotype used as pollen donor. Mixtures containing pollen from G. mustelinum and upland cotton, used to pollinate G. mustelinum in proportions of 25%:75%, 50%:50%, and 75%:25%, produced 61.3%, 22.5%, and 3.6% interspecific hybrids, respectively. These low rates of hybrid production demonstrate that pollen competition is present with G. mustelinum and G. barbadense and confirms this mechanism as a sexual barrier.

No abstract

To maintain the quality of a lawn and allow it to perform its functions (esthetics, enhancement of property, reduction of air temperature, etc.) efficient use of irrigation and adequate fertilization are necessary. The use of wastewater from sewage treatment, which has a nutrient load, in irrigation, can be an alternative especially if applied via subsurface, to reduce contamination risks. This study was conducted to examine the development and quality of an ornamental lawn of Zoysia japonica Steud (zoysiagrass) irrigated with wastewater depths, by two methods. The experiment was carried out in Botucatu-SP, Brazil, during winter and spring (June to December 2016). The treatments consisted of two irrigation methods (sprinkling and subsurface drip) and four domestic-wastewater irrigation depths (50%, 100%, 150% and 200% of the average daily evapotranspiration) plus control, where treated water was supplied by the Basic Sanitation Company of São Paulo State (Sabesp) of Botucatu, SP, Brazil, replacing 100% of average daily evapotranspiration. The following characteristics were studied: clipping dry matter weight, relative chlorophyll content, lawn height, total coliforms and Escherichia coli in the plant tissue and nutrient concentration in the leaves. Subsurface drip irrigation with wastewater, using an irrigation depth of 100% of the average evapotranspiration, allowed an adequate development of the zoysiagrass lawn by maintaining its quality, without contamination by total coliforms or Escherichia coli.

The Juçara palm is native to the Brazilian Atlantic Forest and has significant commercial and environmental potential. Its multiple end-uses have encouraged studies on its climatic requirements, especially in the state of São Paulo, Brazil, where its presence is currently limited due to illegal exploitation. The objective of this study was to conduct an agroclimatic zoning of the Juçara palm tree in São Paulo. Meteorological data from 110 government stations, the Rural Environmental Registry (CAR) and ArcGIS® 10.4 geotechnical tools were used to show temperature, precipitation, and water deficit data in map-like visualizations for reclassified an agroclimatic zoning. A significant proportion of São Paulo State is considered suitable and viable for the Juçara palm, mainly in the south-central and eastern parts of the state and including regions adjacent to large population centers. Considering sufficient economic return, irrigation can be used in regions that are at the lowest limit of the plant’s water demand. For areas where the upper-temperature limit exceeds the recommended temperature for the plant, its cultivation/management should be explored as part of agroforestry systems. Based on our analysis, the CAR environmental registry is effective in identifying areas for the implementation of agroforestry systems.

SALINIZAÇÃO POR POTÁSSIO NA PRODUÇÃO DE PIMENTÃO FERTIRRIGADO SOB AMBIENTE PROTEGIDO     RENAN LIMA DE SOUSA1; ROBERTO LYRA VILLAS BÔAS2; POLIANA ROCHA D’ALMEIDA MOTA3; CAROLINE DE MOURA D’ANDRÉA MATEUS4 E RAFAEL BARCELOS MENDONÇA5   1Programa de Pós-graduação em Agronomia, Universidade Estadual Paulista “Júlio de Mesquita Filho”, UNESP, Avenida Universitária, nº 3780, Altos do Paraíso, CEP 18610-034, Botucatu, SP, Brasil. E-mail: renann.agro@hotmail.com 2Departamento de Solos e Recursos Ambientais, Universidade Estadual Paulista “Júlio de Mesquita Filho”, UNESP, Avenida Universitária, nº 3780, Altos do Paraíso, CEP 18610-034, Botucatu, SP, Brasil. E-mail: rlvboas@fca.unesp.br 3Departamento de Engenharia Agrícola e Solos, Universidade Federal do Piauí, UFPI, Rua Dirce Oliveira, nº 3397, Ininga, CEP 64048-550, Teresina, PI, Brasil. E-mail: poliana@ufpi.edu.br 4Departamento de Solos e Recursos Ambientais, Universidade Estadual Paulista “Júlio de Mesquita Filho”, UNESP, Avenida Universitária, nº 3780, Altos do Paraíso, CEP 18610-034, Botucatu, SP, Brasil. E-mail: caroline_mateus@hotmail.com 5Departamento de Solos e Recursos Ambientais, Universidade Estadual Paulista “Júlio de Mesquita Filho”, UNESP, Avenida Universitária, nº 3780, Altos do Paraíso, CEP 18610-034, Botucatu, SP, Brasil. E-mail: rafael.irrigacao@gmail.com     1 RESUMO   Objetivou-se com a pesquisa avaliar doses de potássio na produção de pimentão, cultivar ‘Gaston’, e efeitos no extrato de solução do solo, utilizando extratores. Instalou-se a pesquisa na estufa agrícola do Departamento de Solos e Recursos Ambientais da Universidade Estadual Paulista “Júlio de Mesquita Filho” - Campus de Botucatu, tendo sido as plantas conduzidas em vasos. Utilizou-se o delineamento experimental em blocos casualizados, quatro repetições, testando quatro doses de K2O (363 kg ha-1, 726 kg ha-1, 1088 kg ha-1 e 1451 kg ha-1) aplicadas via fertirrigação por gotejamento. Foram avaliados: a condutividade elétrica e concentração de íons específicos da solução do solo extraída semanalmente, altura das plantas e produção. Os extratores permitiram monitoramento eficiente e houve diferença significativa entre os tratamentos. O aumento da concentração de sais na solução do solo reduziu a altura das plantas, número de frutos e a produção. A dose, além da calagem, que proporcionou maior produção de frutos foi: 363 kg ha-1 de K2O com 39,2 t ha-1, apresentando condutividade elétrica média ao longo do ciclo de 1,7 dS m-1 e concentração de 111 mg L-1 no extrato de solução do solo.   Palavras chave: Capsicum annuum L., fertirrigação, extrator de solução, solução do solo, salinização     SOUSA, R. L.; VILLAS BÔAS, R. L.; MOTA, P. R. D.; MATEUS, C. M. D.; MENDONÇA, R. B.     EFFECTS OF POTASSIUM SALINIZATION IN THE PRODUCTION OF FERTIRRIGATED RED PEPPERS UNDER GREEN HOUSE     2 ABSTRACT   The objective of this study was to evaluate potassium doses in the production of sweet pepper, 'Gaston' cultivar, and effects on soil solution extract, using extractors. The research was installed in the greenhouse of the Department of Soils and Environmental Resources of São Paulo State University "Júlio de Mesquita Filho" - Botucatu Campus, and the plants were carried in pots. The experimental design was a randomized block design, with four replicates, using four doses of K2O (363 kg ha-1, 726 kg ha-1, 1088 kg ha-1 and 1451 kg ha-1) applied via drip fertirrigation. Electrical conductivity and specific ion concentration of soil solution extracted weekly, plant height and yield were evaluated. The extractors allowed efficient monitoring and there was  significant differences across treatments. Increase in salt concentration  in the soil solution reduced plant height, number of fruits and yield. The dose, in addition liming, that provided the highest fruit yield was: 363 kg ha-1 of K2O with 39.2 t ha-1, with an average electrical conductivity over the cycle of 1.7 dS m -1 and concentration of 111 mg L-1 in soil solution extract.   Keywords: Capsicum annuum L., fertirrigation, solution extractor, soil solution, salinization