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Frequency changes of alleles at eight enzyme loci were monitored in four long-term maize selection experiments. The results indicate that changes in frequencies of the alleles at these loci are associated with changes due to selection for improved grain yield. The frequencies changed more than is consistent with the hypothesis of selective neutrality. In(More)
Genetic and biochemical analyses suggest that the developmental program of catalase (H(2)O(2):H(2)O(2) oxidoreductase, EC activity in maize scutella is controlled by a temporal regulatory gene (Car1) that is distinct from the structural genes thus far identified. Recombination data show that Car1 is located about 37 map units from the Cat2(More)
HE dominant favorable gene hypothesis, first proposed by BRUCE (1910), T attributes heterosis to accumulated effects of loci at which the more favorable allele contributed by one parent is manifest rather than the unfavorable allele contributed by the other parent. The concepts of linkage (JONES 191 7) and large number of loci (COLLINS 1921; SINGLETON 1941)(More)
Experiments with two maize (Zea mays L.) hybrids were conducted to determine (a) if the inhibition of nitrate uptake by aluminium involved a restriction in the induction (synthesis/assemblage) of nitrate transporters, and (b) if the magnitude of the inhibition was affected by the concurrent presence of ambient ammonium. At pH 4.5, the rate of nitrate uptake(More)
A prolific maize (Zea mays L.) genotype was grown to physiological maturity under greenhouse conditions to examine the effects of reproductive sink demand on (a) the remobilization of N accumulated during vegetative growth, and (b) the partitioning of N accumulated concurrent with ear development. One- and two-eared plants were treated with either a NO(3)(More)
Genetic variance components for tuber dormancy in an interpopulation hybrid betweenSolanum tuberosum (Group Phureja) and (Group Stenotomum) were estimated using a N.C. Design II mating plan. The genetic variance estimate was high and was composed entirely of additive variance. The estimate of narrow sense heritability was. 73. The results indicated that(More)
The relative effects of ammonium on nitrate uptake and partitioning during induction were compared among decapitated seedlings of three corn (Zea mays L.) genotypes at two developmental stages. This study tested the hypothesis that root systems efficient at translocating products of ammonium assimilation away from sites of nitrate uptake or reduction would(More)
Ten inbred lines from the open-pollinated maize variety Jarvis were selected from 51 randomly collected lines to represent a wide range of susceptibility to one isolate each of Bipolaris maydis or Colletotrichum graminicola. Ten isolates of each pathogen were selected for a range of virulence on a maize line with average resistance. Resistance and virulence(More)
Experiments in which a series of host cultivars are inoculated in all combinations with a series of pathogen isolates have been used to detect specificity in the host resistance. A theoretical model of polygenic resistance involving both general and specific interactions with pathogen virulence was developed to test the abilities of statistical analyses to(More)