Técnica hidropônica para triagem de genótipos de tomateiro quanto à eficiência de absorção de fósforo

Abstract

Phosphorus (P) is the most limiting nutrient to plant growth and development in acidic soils of tropical and subtropical regions. The objective of this study was to establish a nutrient solution (hydroponics) technique for screening of tomato genotypes for efficiency of phosphorus absorption. An area of 160 m2 within a protective structure covered with 150 micron polyethylene film was used, with masonry-built channels 20 cm wide x 15 cm in height spaced 0.80 m apart. The experimental setup was a split plot design with factorial treatments and four replications. Plots comprised two concentrations of P in nutrient solution (0.50 and 60 ppm), whereas subplots comprised two tomato genotypes with contrasting P absorption efficiencies [PI 121665 (efficient, crt/crt) and TOM-598 (crt+/crt+)]. After this test, the two genotypes were again grown in a completely randomized experimental design with four replications, under the same structure, under concentration of 0.20 ppm P in nutrient solution. We evaluated the fresh mass of aboveground part, dry mass of aboveground part, fresh mass of root, dry mass of root and length, area and volume from the root. The hydroponic technique was effective to screen tomato genotypes for resistance or tolerance to phosphorus deficiency. The concentration of 0.50 ppm P in nutrient solution in NFT hydroponic system was suitable for this purpose.