No abstract

The interpretation of new varieties performance is disturbed under the influence of genotype-by-environment interaction. Among several methods used for understanding this effect, one of the most frequently used methods is Additive Main Effects and Multiplicative Interaction (AMMI) analysis. In this study we used AMMI method with the aim to estimate the genotype - environment interaction of 14 barley genotypes, and to identify barley genotypes that have high and stable performance in different environments. The trials were conducted during 11 growing seasons (1995/96 - 2005/06), arranged in a randomized complete block (RCB) design with four replications in location Rimski Sancevi. The results showed that the influence of environment (seasons), genotypes and their interaction on barley grain yield were significant (p < 0.01). Based on AMMI method, two-rowed variety Novosadski 317 and the six-rowed variety Novosadski 331 can be distinguished due their high and stable yields. [Projekat Ministarstva nauke Republike Srbije, br. TR-31066]

Maize (Zea mays L.) displays large genetic diversity created during the history of introduction from its Mexican centre of origin to other parts of the world and adaptation to a range of diverse environments. Despite such diversity, maize breeders use only a small portion of the available maize germplasm to develop modern hybrids. Broadening diversity of breeding collections by the introduction of new germplasm, as a source of favourable traits, requires its characterisation and classification of new germplasm into heterotic groups. The aim of this study was to estimate genetic diversity of maize breeding material from the Institute of Field and Vegetable Crops in Serbia, including previously uncharacterised inbred lines, elite lines with known pedigrees and historically important inbred lines. Microsatellite-based cluster analysis and principal coordinate analysis separated 96 inbred lines into six clusters, Iowa Stiff Stalk Synthetic (BSSS), Lancaster Sure Crop (LSC), Iodent (IDT) heterotic group, a cluster with unrelated independent inbreds and two clusters of miscellaneous germplasm crossed with inbreds of BSSS and Lancaster background. The microsatellites umc1035, bnlg666, dupssr23, umc1083 and dupssr10 contributed most to the differentiation between the groups. The largest values of molecular diversity parameters were detected in the BSSS group, following by the Lancaster and then the other groups. An analysis of variance showed that almost all traits significantly varied among the groups and between the years. The investigated lines demonstrated sufficient variation in most of the analysed phenotypic traits, proving suitable for further genetic studies. A principal component analysis based on agronomic traits differentiated inbred lines from the BSSS and Lancaster pools, but failed to separate the other groups. The characterisation and classification of genetic resources using microsatellite markers may assist hybrid breeding by efficient exploitation of heterotic patterns.

Seed priming is a useful technique, applied prior to planting, which partially hydrates the seeds to a point of germination process initiation, followed by drying, which prevents radicle emergence. The objective of this study was to evaluate the effect of various seed priming treatments on germination parameters of maize at different temperatures. Seeds were primed in water (hydropriming) and KNO3 solution (0.1% and 0.5%) by soaking at 25°C for 17h. Germination parameters were tested at 25°C, 15-25°C and 15°C. Seed priming had a positive effect on some seed germination parameters at low and mixed temperature. Treatment with 0.5% KNO3 had the most improving effect. This treatment reduced MGT, T50 and increased GE at low and mixed temperature. Priming showed no positive effect on the final germination. This study showed that seed priming with KNO3 could be used to achieve better seedling establishment at low temperature conditions in maize.

Studies on genetic gains in grain yield and other traits may be very useful in providing necessary information to plant breeders about the effectiveness of their breeding programs. The objective of this research was to analyze changes in grain yield, yield stability and morphological characteristics of maize hybrids released in Serbia between 1978 and 2011. Five hybrids, representatives of different breeding periods, were chosen for this study. Field trials were conducted during 2013 and 2014 at three locations in Serbia. The estimated genetic gain per breeding period was 440 kg ha -1 which corresponds to an approximate annual linear increase in yield of 63 kg ha -1 . Changes in morphological characteristics were presented graphically, compared to the reference value and defined by the third period of breeding. Plant and ear height, kernel row number, number of kernels per row and leaf number were reduced compared to the third breeding period. Kernel depth showed higher variation through periods while in other analyzed traits, major changes in value through the periods were not found. Stability analysis distinguished the hybrids from the sixth and seventh period of breeding as the most stable, whereas the most unstable were representatives of the fifth and third period. Changes in certain morphological traits and yield stability have led to an increase in the genetic potential of the hybrids most probably through the increased tolerance to biotic and abiotic stress factors.