The synthetic maize population 316PO2 was subjected to genetic correlation analyses between grain yield, yield components and morphological traits. The purpose was to enable estimates to be made of the advantage of using selection indices compared with selection based on grain yield only, and if that advantage was present, to choose enough simple selection indices for practical use. Selection indices were constructed out of four traits highly significantly correlated with grain yield, in addition to yield itself.Grain yield exhibited a highly significant additive genetic correlation with ear diameter (r a =0.588**), kernels row -1 (r a =0.643**), ears plant -1 (r a =0.871**) and ear height (r a =0.427**). The most efficient index was Index No. 14 (R.E.I 12345 = 108.83%), which included all four traits and grain yield. Index No. 3, one of the simplest forms of index, including only ears plant -1 and grain yield, showed slightly less relative efficiency (R.E.I 35 =107.24%) than Index No. 14. Using this simple form of index with two characters (Index No. 3) could improve the efficiency of selection for grain yield. The estimated advantage from its use is 179.6 kg/selection cycle for grain yield over selection based only on grain yield.

Genetic variation for stay green character has been exploited in maize improvement mainly in the light of selecting high yielding rather then typical stay green genotypes. Stay green is an indicator of good plant health later in the season, reduced progressive senescence, tolerance to post-flowering drought and stalk lodging, what ensure superiority of stay green genotypes in comparison to non-stay green ones, especially in drought conditions. The objective of the study was to examine relationship of stay green trait with some vegetative characters in two genetically broad based maize populations. The most consistent correlations with stay green were established for leaf and stalk water content, which has been confirmed by path-coefficient analysis

Inbred lines B73 and Mol7 or some versions thereof are the most commonly used parental pair in the development of medium late and late maize hybrids in Serbia and Montenegro. Because of the ever-increasing importance of line B73 in maize hybrid production, we chose several B73-type lines and a few unrelated lines and crossed them. Using the pedigree method, progenies were developed up to the S6 generation. The grain yield potential of test crosses with Mo 17 inbred tester, as well as ear length, number of grain rows per ear and 1,000-grain mass of lines per-se were tested. Among the new inbred lines related to B73, line 260277/2 distinguished itself by a high potential for grain yield when crossed with Mo 17. Inbred lines 260465/1, 260362/1, 260747/4, 260357/13, 260151/2 and 260156/2 had a significantly longer ear than the mean value of all progenies. Compared with progeny mean, lines 260341/7, 260317/4, 260277/2 and 260187/2 had significantly more grain rows per ear, while 260362/1, 260130/5, 260277/2, 260151/2 and 260187/2 had a significantly larger 1,000-grain mass

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