Inheritance of atrazine tolerance in South African maize

Abstract

Forty-five maize (Zea mays L.) inbreds were screened for tolerance to atrazine (2-chloro-4-ethylamino-6- isopropylamino-1, 3, 5-triazine) in a glasshouse using a sand culture technique. Ten inbreds displaying a spectrum of tolerance were hybridized in all possible combinations including reciprocals to yield 90 F1 crosses. The ten inbreds and 90 F1 crosses were evaluated for tolerance to atrazine (8 ppm v/v) under controlled conditions. A second diallel composed of eight inbreds and 28 F1 crosses without reciprocals were similarly evaluated. Leaf mass data strongly indicated additive gene effects and a degree of cytoplasmic inheritance was also evident. Significant amounts of heterosis also existed. Broad-sense heritability values (0,70 and 0,42) confirmed the potential for increasing hybrid tolerance to atrazine by breeding.

Keywords:

• Atrazine tolerance
• gene effects
• inheritance
• Zea mays