Development of cotton variety IAPAR 4 - Paraná 1

São apresentados e discutidos dados de 46 ensaios conduzidos por seis anos agrícolas no Estado do Paraná, com a linhagem PR 4139, originária de seleção individual de plantas na variedade Réba B-50. São mostrados dados comparativos com as variedades em cultivo, e características morfológicas diferenciais. O material recebeu o nome de "IAPAR 4 - Paraná 1" e é recomendado, no Estado, para áreas de solos argilosos e comprovadamente sem problemas de murcha e nematóide.Data from 46 field experiments carried out during six years in the State of Paraná, with tine PR 4139, originated from individual selection in Reba B-50 variety, are presented and discussed. Comparison between cultivated varieties is made, and morphological characters are described. The line received the name IAPAR 4 Paraná 1" and is recommended in the State for areas with clay soils and free from wilt.

Cotton zoning based on sowing periods of lower risk in Parana state, Brazil

Cotton is cultivated in the North and West of Parana State, southern Brazil, under conditions of climatic risk variable in space and time. Risks of temperature below 15ºC at the establishment period, daily average temperature below 20ºC at the stage of cotton boll opening, and soil water deficit for both plant establishment and flowering periods, were estimated to identify homogeneous zones with sowing periods of lower climatic risk. The time interval with adequate temperature, associated with minimum risks of the other factors and yield data from field experiments allowed the identification of seven distinct zones, with best sowing periods ranging from September 20 to November 20. Official credit to the farmers is conditioned by the Central Bank of Brazil upon following these recommendation of best sowing periods for each municipality