CORNGRASS1 OF MAIZE (ZEA-MAYS L) DELAYS DEVELOPMENT OF ADULT-PLANT RESISTANCE TO COMMON RUST (PUCCINIA-SORGHI SCHW) AND EUROPEAN CORN-BORER(OSTRINIA-NUBILALIS HUBNER)
Bg. Abedon et Wf. Tracy, CORNGRASS1 OF MAIZE (ZEA-MAYS L) DELAYS DEVELOPMENT OF ADULT-PLANT RESISTANCE TO COMMON RUST (PUCCINIA-SORGHI SCHW) AND EUROPEAN CORN-BORER(OSTRINIA-NUBILALIS HUBNER), The Journal of heredity, 87(3), 1996, pp. 219-223
Based on morphological evidence, researchers have proposed that Corngr
ass1 (Cg1) of maize (Zea mays L.) is a heterochronic mutation that pro
longs the juvenile-vegetative phase because distal tissues display juv
enile traits that normally occur only basally, Physiological or bioche
mical evidence in support of this hypothesis is lacking, Disease and i
nsect resistance often depends on physiological, biochemical, and morp
hological factors and can vary during ontogeny, We evaluated resistanc
e to common rust (Puccinia sorghi Schw,) and European corn borer (Ostr
inia nubilalis Hubner) in cg1 and wild-type segregating families in or
der to test the hypothesis that Cg1 is a heterochronic mutation that e
xtends the juvenile-vegetative phase, In backgrounds with high express
ion, Cg1 mid-whorl leaves had similar resistance as Cg1 and wild-type
seedling leaves, whereas wild-type mid-whorl leaves differed in resist
ance from the other three leaf types, In the Mo17 background, which ha
s reduced Cg1 expression, Cg1 mid-whorl leaves had resistance levels i
ntermediate between wild-type seedling and mid-whorl levels, These res
ults support the hypothesis that Cg1 prolongs the juvenile-vegetative
phase and suggest that heterochrony may be among the factors responsib
le for disease and insect resistance in normal populations of maize.