SELECTION OF MAIZE BREEDING POPULATIONS UNDER HIGH AND LOW PHOSPHORUS DOSE IN A CERRADO SOIL

Abstract

The objective of this research was to obtain and select maize base populations, efficient in phosphorus absorption and utilization, in a savannah soil, in the municipality of Gurupi, Tocantins State, Brazil (11°43’S, 49°15’W, altitude 300 m). The study assessed 45 hybrid combinations (populations), derived from crosses among ten commercial hybrids, in a dystrophic red-yellow Latossol (Oxisol), under low (25 kg ha^-1 of P₂O₅) and high (113 kg ha^-1 of P₂O₅) phosphorus doses. The traits evaluated were grain yield, plant height, ear height, and number of days for female flowering. The data were submitted to variance analyses and the means of genetic treatments were grouped by the Scott-Knott test. The populations with outstanding behavior in both environments and, therefore, most adapted to the target region, are derived from the following crosses: CO 32 x DKB 350, Z 8480 x CO 32, Z 8480 x P30F88, C 901 x CO 32, C 901 x P30F88, Z 8480 x DKB 350, CO 32 x Z 8420, C 901 x Z 8420, C 901 x C 333 B, Z 8420 x DKB 350, C 901 x Z 8480, DKB 350 x Z 8410, P30F88 x Z 8420, AG 9010 x DKB 350, and P 3041 x AG 9010. It was also concluded that the populations show plant height and ear height appropriate for growing in the region, and that the environment with the lowest dose of phosphorus delays the flowering of the populations.

KEY-WORDS: Zea mays; P low input; P mineral stress; Cerrado soil.