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The Mostly used, classical parametric approaches for an analysis of genotype x environment interaction are based on several assumptions: normality of: the distribution, homogeneity of variances, additivity. If some of mentioned assumptions are not fulfilled, the validity of these methods may be questionable. By use of nonparametric methods, which are simple and easy for analysis, all of the mentioned assumptions are avoided. in this paper we used several of non parametric techniques for analysis of genotype x environment interaction for grain yield of 24 maize (Zea mays Q hybrids through two locations in two years. Values of the stability measures shown that hybrids with the highest grain yield in the majority of cases were not the most stable. So as the value of the relative deviation in relation to the average rank classified the lowest yielding (4.9 t ha(-1)) genotype PR36B08 as the most stable genotype (S-i((3)) = 0.12). The interrelations of numerical values among methods, indicating the genotype x environment interaction obtained in this study, are different than the relation given by HUHN (1996), hence the order is as follows: van der Laan and de Kroon>KubingerHildebrand The Values of mean differences among ranks over different environments (S-i((1))) were ranged froin 2.33 to 14.83. The values of variance among ranks (Si(2)) varied from 3.33 to 154.92, while values of the relative deviations in relation to the average rank (Si 6)) ranged from 0.12 to 15.55. more...

The Mostly used, classical parametric approaches for an analysis of genotype x environment interaction are based on several assumptions: normality of: the distribution, homogeneity of variances, additivity. If some of mentioned assumptions are not fulfilled, the validity of these methods may be questionable. By use of nonparametric methods, which are simple and easy for analysis, all of the mentioned assumptions are avoided. in this paper we used several of non parametric techniques for analysis of genotype x environment interaction for grain yield of 24 maize (Zea mays Q hybrids through two locations in two years. Values of the stability measures shown that hybrids with the highest grain yield in the majority of cases were not the most stable. So as the value of the relative deviation in relation to the average rank classified the lowest yielding (4.9 t ha(-1)) genotype PR36B08 as the most stable genotype (S-i((3)) = 0.12). The interrelations of numerical values among methods, indicating the genotype x environment interaction obtained in this study, are different than the relation given by HUHN (1996), hence the order is as follows: van der Laan and de Kroon>KubingerHildebrand The Values of mean differences among ranks over different environments (S-i((1))) were ranged froin 2.33 to 14.83. The values of variance among ranks (Si(2)) varied from 3.33 to 154.92, while values of the relative deviations in relation to the average rank (Si 6)) ranged from 0.12 to 15.55. more...

Formation of the maize (Zea mays L) core collection for increased macronutrient content is presented. Among 3,443 populations from Maize Research Institute (MRI), Zemun Polje (ZP), a total of 352 accessions (around 10.2%) were chosen for the core collection. The criteria were increased protein, oil and/or starch content in the kernel of the accessions, as well as good combining ability (CA) that was tested with two Lancaster and one each BSSS and Iodent testers. Average values for protein, oil and starch content for the whole collection were 11.5%, 4.2% and 68.9%, respectively. On the other hand, averages for the core collection were 13.6% for proteins, 7.7% for oil and 74.1% for starch, and they were significantly higher than for the whole collection (p lt 0.001). Small negative, but highly significant correlations were found for protein content and latitude (-0.119; p lt 0.01), as well as for starch content and altitude (-0.090; p lt 0.01) of the collection sites for Western Balkan landraces. Positive small significant correlations were obtained for oil and altitude (0.069; p lt 0.05) and starch and latitude of (0.077; p lt 0.05) collection site, while medium highly significant positive correlation was found for protein content and altitude of collection site (0.237; p lt 0.01). Eighteen populations with increased protein and/or oil content and with good universal combining ability (with Lancaster, BSSS, and Iodent testers) were chosen to form the mini-core collection for grain quality, and they are planned for further detailed biochemical, phenotypic and genetic characterisation. more...

Formation of the maize (Zea mays L) core collection for increased macronutrient content is presented. Among 3,443 populations from Maize Research Institute (MRI), Zemun Polje (ZP), a total of 352 accessions (around 10.2%) were chosen for the core collection. The criteria were increased protein, oil and/or starch content in the kernel of the accessions, as well as good combining ability (CA) that was tested with two Lancaster and one each BSSS and Iodent testers. Average values for protein, oil and starch content for the whole collection were 11.5%, 4.2% and 68.9%, respectively. On the other hand, averages for the core collection were 13.6% for proteins, 7.7% for oil and 74.1% for starch, and they were significantly higher than for the whole collection (p lt 0.001). Small negative, but highly significant correlations were found for protein content and latitude (-0.119; p lt 0.01), as well as for starch content and altitude (-0.090; p lt 0.01) of the collection sites for Western Balkan landraces. Positive small significant correlations were obtained for oil and altitude (0.069; p lt 0.05) and starch and latitude of (0.077; p lt 0.05) collection site, while medium highly significant positive correlation was found for protein content and altitude of collection site (0.237; p lt 0.01). Eighteen populations with increased protein and/or oil content and with good universal combining ability (with Lancaster, BSSS, and Iodent testers) were chosen to form the mini-core collection for grain quality, and they are planned for further detailed biochemical, phenotypic and genetic characterisation. more...

Since the discovery of the pest in 1992, western corn rootworm (Diabrotica virgifera virgifera LeConte (WCR)) populations in Serbia have successfully been kept low with crop rotation. This has reduced the efficiency of screening maize for WCR resistance. A cooperative project between Iowa State University and the Maize Research Institute, Zemun Polje evaluated 13 Serbian commercial maize varieties in Ames, Iowa over a two-year period using the difference approach. Maize hybrids were planted on trap crops where high WCR populations were assumed. Hybrids were evaluated for WCR resistance using a randomized complete block design with four replications. Treatments were paired-rows arranged in split plots with one row in each pair treated with insecticide and the other row left untreated. WCR injury was evaluated using a rating of root size and root re-growth (1-6 scale), root injury (0-3 Node-Injury Scale), root mass, lodging, and yield. The results indicated significant differences among the Serbian hybrids in the presence of moderate-to-high levels of western corn rootworms. The relative benefit of insecticide treatments for maize hybrids was a useful tool in evaluating resistant germplasm. However, conducting analyses on relative differences between insecticide treated and untreated plots was not as effective at detecting differences as comparing the plots independently. more...

Since the discovery of the pest in 1992, western corn rootworm (Diabrotica virgifera virgifera LeConte (WCR)) populations in Serbia have successfully been kept low with crop rotation. This has reduced the efficiency of screening maize for WCR resistance. A cooperative project between Iowa State University and the Maize Research Institute, Zemun Polje evaluated 13 Serbian commercial maize varieties in Ames, Iowa over a two-year period using the difference approach. Maize hybrids were planted on trap crops where high WCR populations were assumed. Hybrids were evaluated for WCR resistance using a randomized complete block design with four replications. Treatments were paired-rows arranged in split plots with one row in each pair treated with insecticide and the other row left untreated. WCR injury was evaluated using a rating of root size and root re-growth (1-6 scale), root injury (0-3 Node-Injury Scale), root mass, lodging, and yield. The results indicated significant differences among the Serbian hybrids in the presence of moderate-to-high levels of western corn rootworms. The relative benefit of insecticide treatments for maize hybrids was a useful tool in evaluating resistant germplasm. However, conducting analyses on relative differences between insecticide treated and untreated plots was not as effective at detecting differences as comparing the plots independently. more...

The initial idea of this paper was a hypothesis that upright leaves of maize inbred lines were characteristic for an efficient photosynthetic model and that as such were very desirable in increasing the number of plants per area unit (plant density) in the process of contemporary breeding and seed production. The application of a semi in vivo photosynthetic bioluminescence method (leaf segment is still alive and all process are active), suitable for the efficiency estimation of the model, verified the hypothesis. Obtained photosynthetic properties of observed upright leaves of maize inbred lines were based on the effect and photosynthetic characteristics of thermal processes of delayed chlorophyll fluorescence (DF) occurring in their thylakoid membranes. The temperature dependence of the delayed chlorophyll fluorescence intensity, phase transition (critical temperatures) and activation energy are the principal photosynthetic parameters of the thermal processes in the thylakoid membrane. Based on obtained photosynthetic and bioluminescence properties it is possible to select maize inbred lines having upright leaves that are resistant and tolerant to high and very high temperatures, as well as to drought. The selected maize inbred lines could be considered as the efficient photosynthetic model and as such could be used in the improvement of the contemporary maize breeding and seed production. more...

The initial idea of this paper was a hypothesis that upright leaves of maize inbred lines were characteristic for an efficient photosynthetic model and that as such were very desirable in increasing the number of plants per area unit (plant density) in the process of contemporary breeding and seed production. The application of a semi in vivo photosynthetic bioluminescence method (leaf segment is still alive and all process are active), suitable for the efficiency estimation of the model, verified the hypothesis. Obtained photosynthetic properties of observed upright leaves of maize inbred lines were based on the effect and photosynthetic characteristics of thermal processes of delayed chlorophyll fluorescence (DF) occurring in their thylakoid membranes. The temperature dependence of the delayed chlorophyll fluorescence intensity, phase transition (critical temperatures) and activation energy are the principal photosynthetic parameters of the thermal processes in the thylakoid membrane. Based on obtained photosynthetic and bioluminescence properties it is possible to select maize inbred lines having upright leaves that are resistant and tolerant to high and very high temperatures, as well as to drought. The selected maize inbred lines could be considered as the efficient photosynthetic model and as such could be used in the improvement of the contemporary maize breeding and seed production. more...