Varietal differences in development of maize (Zea mays L.) seedlings on compacted soils

Differences among open-pollinated tropical maize (Zera mays L.) varieties i n seedling development and establishment on compacted soils were studied. S oil dry density was used as an index of compaction. Three soil compaction l evels and 12 traits associated with development and establishment of maize seedlings were investigated. A control (without compaction) was also includ ed. Varietal differences were observed for most traits measured. Genetic di fferences for seedling development on compacted soil were detected. Varieta l differences contributed about three times the contribution of compaction to total variability in the traits. Better seedling development and perform ance were obtained in moderately compacted soil than in the control. Shoot length, shoot dry weight and per cent dry matter in roots were good indicat ors of the tolerance of maize seedlings to compaction. A physiological stra tegy for maize seedling establishment on compacted soil was proposed. The i mplications of the results for seed testing were also highlighted. It was c oncluded that consideration should be given to the genotype of maize destin ed for use in ecologies prone to high soil densities. All varieties of maiz e grown in an agroecological zone could be screened to identify genotypes t olerant of higher soil densities. The seeds could then be multiplied and di stributed to farmers.