Correlation and path analysis of grain yield and morphological traits in test–cross populations of maize

One of the goals of this paper was to determine correlation between grain yield, like the most important agronomic trait, and traits of the plant and ear that are influencing on the grain yield, in two test-cross populations, which are formed by crossing progenies of NSU(1) population after 17 cycles of phenotypic recurrent selection and two testers, 568/II NS and B73. At 568/II NS testcrosses, grain yield had the highest value of genotypic coefficient of correlations with kernel row number. In second studied population the highest value of coefficient of correlations also was found between grain yield and kernel row number, but that relation was negative. Path coefficient analysis provides more information among variables than do correlation coefficients. Because of that goal of this study also was founding the direct and indirect effects of morphological traits on grain yield. Desirable, high significant influence on grain yield, in path coefficient analysis, was found for ear height, in both studied populations. Plant height, in both testcross populations, kernel row number and oil content, at B73 testcrosses, has high significant undesirable effect on grain yield.