Commercial maize hybrids are exposed to different degrees of ear infection by toxigenic fungal species and toxin contamination. Their resistance to different fungi and toxin relationships are largely unknown. Without this knowledge, screening and breeding are not possible for these pathogens. Seven- to tenfold differences were found in resistance to Fusarium spp., and there was a five-fold difference in ear coverage (%) in response to A. flavus. Three hybrids of the twenty entries had lower infection severity compared with the general means for toxigenic species. Three were highly susceptible to each, and 14 hybrids reacted differently to the different fungi. Differences were also observed in the toxin content. Again, three hybrids had lower toxin content in response to all toxigenic species, one had higher values for all, and 16 had variable resistance levels. Correlations between infection severity and deoxynivalenol (DON) content were 0.95 and 0.82 (p = 0.001) for F. graminearum and F. culmorum, respectively. For fumonisin and F. verticillioides ear rot, the Pearson correlation coefficient (r) was 0.45 (p = 0.05). Two independent isolates with different aggressiveness were used, and their mean X values better described the resistance levels. This increased the reliability of the data. With the introduction of this methodological concept (testing the resistance levels separately for different fungi and with two isolates independently), highly significant resistance differences were found. The resistance to different fungal species correlated only in certain cases; thus, each should be tested separately. This is very useful in registration tests and post-registration screening and breeding. This would allow a rapid increase in food and feed safety.
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.
The development of irrigation schedules based on water balance implies a study of daily plant water requirements. A properly selected irrigation method is also of most importance. The objective of this study was to find out how surface drip irrigation (SDI) and shallow subsurface drip irrigation (SSDI), as well as different ET-based irrigation scheduling for maize (reference evapotranspiration (ETo), pan evaporation (Eo), and local climatic coefficients (lc)), affect grain yield, water use efficiency (WUE), and yield response factor (Ky) of maize. The field experiments were conducted in Vojvodina, a northern part of the Republic of Serbia, on the calcareous gleyic chernozem soil, using a complete block design in three replicates in 2019–2021. The water balance method was used for irrigation scheduling. The nonirrigated treatment was used as a control. The yield in irrigation conditions was statistically higher as compared with the nonirrigated control variant. Concerning the tested parameters, especially the maize yield, reference evapotranspiration (ETo) should be recommended as the most acceptable method for assessing maize evapotranspiration. Preference should be given to SSDI compared to SDI because the installation of laterals can be performed together with the sowing, which can ensure the uniform and timely emergence of plants. Based on the Ky coefficient of 0.71, it can be concluded that maize is moderately tolerant to water stress in Vojvodina’s temperate climate. The results can contribute to precise planning and efficient irrigation of maize in the region, implying high and stable yields.
The study analyzed two-year results of a testing of 20 new maize hybrids from FAO MG 600 as compared to a standard. Data on the hybrids NS6683, NS6686, NS281633, and NS396432 are discussed in the paper in greater detail. In order to study grain yield, grain moisture, root and stalk lodging, and resistance to pests and diseases, field trials using a RCB design with four replicates were conducted in six locations in 2009 and five locations in 2010. The results were presented in the form of GGE biplots in order to rank hybrids relative to the standard while taking into account the genotype x environment interaction and to identify the highest-yielding genotypes in different environments. It was determined that the new NS hybrids had higher grain yield than the standard by 0.883 to 1.720 tha-1, lower grain moisture by 0.85 to 2.54%, better tolerance to root and stalk lodging, and pest and disease resistance on a par to the standard. The study identified so-called ideal locations for particular hybrids, which may be of use when determining which areas the hybrids are best suited for.
Maize breeders consider tolerance to drought as an important criterion in commercial breeding programs. Two traits, stay green and anthesis-silking interval seem to be closely associated with drought tolerance. The main objective of this study was to obtain estimates of means, variability, heritability and estimates of genetic correlations for several traits in two maize synthetic populations. S1 progenies were evaluated in an incomplete block design in four environments. Large genetic variability existed for all traits in both populations but highest variability was found for anthesis-silking interval. Strong, highly significant correlations between drought adaptive traits and grain moisture may cause some undesirable correlative response throughout cycles of selection.