Assessing ecological risks and benefits of genetically modified crops 99

Abstract: Genetically modified (GM) crops and biotechnology are providing new opportunities for increasing crop productivity and tackling agriculture problems, such as diseases, pests and weeds, abiotic stress and nutritional limitations of staple food crops. As GM crops are being adopted in various locations with different ecosystems, a scientifically based understanding of the environmental effects of cultivations of GM crops would assist decision makers worldwide in ensuring environmental safety and sustainability. In this paper are discussed some of the most important problems related to the GM crops into the environment such as: plant protection, hybridisation, ecological effects of HRCs, gene flow, biodiversity, stress, ecological risks (ERA), effects on the soil ecosystem etc

Photosynthetic properties of elite erect leaf maize inbred lines and their contribution to seed production improvement

A hypothesis that elite erect leaf maize inbred lines are characterized by properties of an efficient photo-model and that as such are very desirable in increasing the number of plants per unit area (plant density) in the process of seed production has been confirmed in the present study. The properties of the observed elite erect leaf maize inbred lines were based on the effects and characteristics of thermal processes of delayed chlorophyll fluorescence occurring in their thylakoid membranes. The temperature dependence of the delayed chlorophyll fluorescence intensity, the Arrhenius plot for the determination of phase transitions (critical temperatures) and activation energy are the principal parameters of the thermal processes. Based on the obtained results on photosynthetic properties it was also possible to estimate the tolerance and adaptation of elite erect leaf maize inbred lines to high temperatures and drought

Problems in weed control in Serbian maize seed production

Weed control in the seed maize production is facing some specific problems. Maize inbred lines are known to be susceptible to many stress factors, including actively growing weeds and some herbicides. The slower growth of maize inbreds, as well as, the open space between rows provide favourable conditions for emergence and growth of weeds during the whole growing season. Herbicide combinations applied in the seed maize production are the same as those applied in the commercial maize production, but, their efficiency is differently expressed in these crops. Environmental factors significantly affect weeds and maize development, as well as, herbicides affect maize inbred lines. The introduction of sulfonylurea herbicides, controlling grass weeds, has resulted in susceptibility of a greater number of maize inbred lines. Therefore, it was found that reaction of maize inbred lines gives a wide variability to sulfonilurea herbicides. Considering specificity of maize inbred lines, this study presents some problems in weed control in maize seed production

Assessing ecological risks and benefits of genetically modified crops

Genetically modified (GM) crops and biotechnology are providing new opportunities for increasing crop productivity and tackling agriculture problems, such as diseases, pests and weeds, abiotic stress and nutritional limitations of staple food crops. As GM crops are being adopted in various locations with different ecosystems, a scientifically based understanding of the environmental effects of cultivations of GM crops would assist decision makers worldwide in ensuring environmental safety and sustainability. In this paper are discussed some of the most important problems related to the GM crops into the environment such as: plant protection, hybridisation, ecological effects of HRCs, gene flow, biodiversity, stress, ecological risks (ERA), effects on the soil ecosystem etc

Sixty years of ZP maize hybrid breeding

The modern ZP maize hybrids breeding at the Maize Research Institute, Zemun Polje, begun during the fifties of the 20(th) century. Collecting of the initial material was the first step in conducting maize breeding programs. The maize inbred line-developing programs from three local populations has initiated in 1953. That was beginning of breeding first cycles ZP maize hybrids. From that period up to present time, we have had five generations of ZP maize hybrids. Each generation has characterized by introduction of the new potentially higher yielding hybrids and with better other agronomics characteristics. According to results from different studies, the genetic yield potential of ZP maize hybrids over the last 40 years amounted to 100 kg.ha(-1) per year. ZP 755 was the first registered maize hybrid in the country in 1964. Total 499 ZP maize hybrids have released by the State Government Commission's since 1964 and 99 ZP maize hybrids have registered in 15 countries. Since the seventies biotechnology methods have been applied in the breeding programs. The main part of biotechnology work is based on the molecular marker application for determining genetic diversity, QTL mapping for drought tolerance and identification of chromosome regions harbouring QTLs for economically important traits (yield, kernel oil content)

Photosynthetic properties of erect leaf maize inbred lines as the efficient photo-model in breeding and seed production

The initial idea of this study was a hypothesis that erect leaf maize inbred lines were characterized by properties of an efficient photo-model and that as such were very desirable in increasing the number of plants per area unit (plant density) in the process of contemporary selection and seed production. The application of a non-invasive bioluminescence-photosynthetic method, suitable for the efficiency estimation of the photo-model, verified the hypothesis. Obtained photosynthetic properties of observed erect leaf maize inbred lines were based on the effects and characteristics of thermal processes of delayed chlorophyll fluorescence occurring in their thylakoid membranes. The temperature dependence of the delayed chlorophyll fluorescence intensity phase transitions (critical temperatures) in the thylakoid membranes and activation energy are the principal parameters of the thermal processes. Based on obtained photosynthetic properties it is possible to select erect leaf maize inbred lines that are resistant and tolerant to high and very high temperatures, as well as, to drought. They could be good and efficient photo-models wherewith