ABSTRACT.
Phosphorus use efficiency in pima cotton (Gossypium barbadense L.) genotypes

Elcio Santos1*, Nericlenes Marcante2, Takashi Muraoka1, and Marcos Camacho3
 
In the Brazilian Cerrado, phosphorus (P) deficiency restricts cotton production, which requires large amounts of phosphate fertilizer. To improve the yield of cotton crops, genotypes with high P use efficiency must be identified and used. The present study evaluated P uptake and use efficiency of different Gossypium barbadense L. genotypes grown in the Cerrado. The experiment was carried out in a greenhouse with a completely randomized design, 15 × 2 factorial treatment structure (15 genotypes × 2 P levels),a and four replicates. The genotypes were MT 69, MT 70, MT 87, MT 91, MT 92, MT 94, MT 101, MT 102, MT 103, MT 105, MT 106, MT 110, MT 112, MT 124, and MT 125; P levels were sufficient (1000 mg pot-1, PS treatment) or deficient (PD treatment). Dry matter (DM) and P levels were determined in cotton plant parts and used to calculate plant P content and use efficiency. In general, DM and P content were higher in the PS than in the PD treatment, with the exception of root DM and total DM in some genotypes. Genotypes also differed in terms of P uptake and use capacity. In the PS treatment, genotypes MT 92 and MT 102 had the highest response to phosphate fertilization. Genotype MT 69 exhibited the most efficient P uptake in the PD treatment. Genotype MT 124 showed the best shoot physiological efficiency, apparent recovery efficiency, and utilization efficiency, whereas MT 110 exhibited the highest root physiological efficiency.
Keywords: Nutritional efficiency, phosphorus supply, pima cotton.
1Universidade de São Paulo, Centro de Energia Nuclear na Agricultura, Av. Centenário, 303, São Dimas, Piracicaba, São Paulo, Brasil. *Corresponding author (elciosantos@cena.usp.br).2Universidade de São Paulo, Escola Superior de Agricultura “Luiz de Queiroz”, Av. Pádua Dias 11, Piracicaba, São Paulo, Brasil.3Universidade Estadual de Mato Grosso do Sul (UEMS), Rodovia Aquidauana/UEMS km 12, CEP 79200-000, Aquidauana, Mato Grosso do Sul, Brasil.