Jerko Gunjača

Quantitative inheritance of some wheat plant traits

The objective of this study was to estimate gene effects and genetic variability for some quantitative traits of two winter wheat crosses (Soissons/Zitarka and Soissons/Sana) by generation mean analysis. In most cases a digenic epistatic model was sufficient to explain variation in generation means. The additive-dominance model was adequate for plant height and grain weight per spike of the longest culm. In two cases (grain yield per plant and single grain weight) these models failed to explain variation in generation means, implying the presence of higher order interactions or interactions between linked loci. Dominance effects and additive x additive epistasis were more important than additive effects and other epistatic components. Only complementary type epistasis was observed. The estimated values of narrow-sense heritability (h2n) varied for plant height (54-81%), number of heads per plant (9-76%), number of grains per spike (11-99.8%), grain weight per spike (23-73%), grain yield per plant (21-78%) and single grain weight (49.7-72%). The adequacy of certain modes of inheritance as well as the importance and significance of gene effects and genetic components of variance for analyzed traits were dependent upon the particular crossing combination and experimental site.

Discriminating maize inbred lines using molecular and DUS data

Growing numbers of candidate varieties, decrease of their variability for morphological traits, and internationalization of the national list all contribute to excessive increase of the trial costs, thus creating the need for the improvement of current variety evaluation procedures, especially regards their distinctness, Uniformity, and Stability (DUS) component. Due to rapid advancement in molecular techniques, the use of molecular markers in DUS testing as a complement to, or replacement of, morphological observations became the subject of great interest in scientific studies, and consequently topic for discussion within International Union for the Protection of New Varieties of Plants (UPOV). In order to explore the potential of simple sequence repeat (SSR) markers for distinctness tests, present study involved set of 41 maize inbred lines that were scored for 32 DUS characters prescribed by UPOV and genotyped at 28 SSR loci. Results were largely in favor of the use of molecular markers, revealing or confirming their already known advantages over morphological markers like better consistency with the pedigree, and relatively higher discriminative power. However, their integration into DUS testing protocols still depends upon resolving of several important issues.

Western corn rootworm adult captures as a tool for the larval damage prediction in continuous maize

Continuous maize production in Croatia and Central Europe is at serious risk from western corn rootworm (WCR) (Diabrotica virgifera virgifera, LeConte) activity. When alternatives to sowing continuous are not feasible, farmers will need a reliable tool that will allow them to choose fields for continuous cultivation. The decision could be based on assessing the adult populations in fields from the previous year. Non‐baited yellow sticky traps [Pherocon AM (PhAM)] could be utilized as a practical tool for sampling. The main objective of this study was to determine which WCR adult population data collected by PhAM traps could most reliably predict the subsequent WCR larval population and damage. Adult WCR population densities in 30 cornfields were determined weekly over a 74 day period each year (24th to 35th week) from 2006 to 2009. In addition to root damage and plant lodging measurements, soil and root sampling were conducted to measure the WCR larval population in continuous maize fields. Larval infestation is best predicted by maximal weekly capture (MWC) but, root damage is better predicted by capture of adults in the 31st week of previous year. For the prediction of plant lodging, MWC, average daily capture (ADC) and the capture of adults in 29th week were found to be equivalent. To save money and to shorten the sampling period, farmers should employ PhAM traps between the 29th and 32nd week. The estimated WCR adult capture that could cause significant larval infestation is ≥22 adults/trap in the 29th week. Significant future root damage is predicted if ≥41 adults/trap are captured in the 31st week. Plant lodging is predicted if ≥36 adults/trap (for 90% of upright plants) or ≥32 adults/trap (for 10% of partially lodged plants) are captured in 29th week. Findings will help to develop economic threshold models and improved decision‐making for WCR management.

Comparison of different planting methods in relation to grain yield of wheat

The objective of this paper was to evaluate the adequacy of different methods of planting in small plots and compared with the grain yield rank of wheat genotypes in large plots under different planting densities. Significant differences were found among cultivars, same cultivars under different planting densities, years of testing and planting densities. The estimated values of heritability in narrow sense for grain yield were high and varied from 68 to 99 %, depending on the method of planting and planting density. Comparison of correlation among cultivar’s rank between Method 1 (planting with drilling machine) and other Methods (manual planting) revealed that these relationships were dependant upon the year of testing and varied from low to high, positive or negative and from significant to non-significant. The highest correlation was found between Method 1 and Method 3 (20 kernels/hill) in both years of testing. If we wish to test a larger number of genotypes from gene bank collections or advanced lines in early phase of breeding program for grain yield on small plots we can recommend the use of hill plots with planting density as close as possible to those in large plots.

Genotypic and environmental variability of yield from seven different crops in Croatian official variety trials and comparison with on- farm trends

Assessment of the value for cultivation and use (VCU) of a new cultivar, essential for its official registration, is done through a series of trials carried out over a 2–3-year period and across many locations. In a set of multi-environment VCU trials, evaluation of new genotypes can be a laborious task due to the presence of genotype by environment interactions, which can hide their true genetic value. In an attempt to reveal the true genetic value of new cultivars, a good starting point is investigation of the importance of various genetic and environmental sources of variation, which can be done by estimating relative magnitude of corresponding variance components within the mixed model framework. Genotype × location × year (G × L × Y) data set for seven crops taken from the 10-year period 2001–10 was used in the present study to estimate the variance components for main effects and their interactions in Croatian VCU trials. Depending on the crop, the most important and least important components were Y or LY, and L or GL, respectively. Genotypic effect was relatively small, ranging from 2·1 to 13·4% of the total variation. The current results are comparable with the relative sizes of the variance components obtained in studies from four- to sixfold larger countries, indicating that the environments within Croatia, if sufficiently widely sampled, can provide as extreme cultivar responses as a geographically more dispersed set of VCU trials. The gap range in different crops is much wider (30–60%) than in Western Europe (up to 30%), but it remained constant over the 10-year period.

Interpretation of GEI Effect Analysis for Some Agronomic and Quality Traits in Ten Winter Wheat (Triticum aestivum L.) Cultivars

Ten winter wheat (Triticum aestivum L.) cultivars were tested in randomized complete block design (RCBD) trials at one location (Osijek) for several agronomic and quality traits through six growing seasons (1996/97–2001/02). Data were employed to develop modeling strategy for exploring genotype by environment interaction (GEI) by using models based on information on genotypic and environmental variables. The relative size, hence importance of the GEI compared to main effects of genotypes and environments was estimated for all effects from simple additive model (genotypes, environments and residuals, last including both GEI and experimental error) while the AMMI2 model was used as a basis for comparison of the GEI patterns. The final step in modeling strategy was fitting factorial regression models to all analyzed traits using available genotypic and environmental covariates, until the best fit solution was found for each analyzed trait.

Genotype by environment interaction in variety trials

Data sets from official variety trials carried out in Croatia from 1992 to 1998 were analyzed using EM-AMMI models. Amount of missing cells in all four data sets (winter wheat, spring barley, winter barley, spring oats) was more than 60%. Only for spring oats data sets cross validation procedure detected AMMI1 as the best model, while for remaining three data sets detected best models were either too complex or too noisy.

Protein content in common bean row seeds in relation to a* and b* dimensions of the L*a*b* color space

Abstract Background: In Egypt, liver diseases are one of the most prominent killers especially hepatitis virus infection, fibrosis and cirrhosis . Hepatitis has a serious health effects and alter the functions of the

Phosphorus dynamics in grapevine on acid and calcareous soils

Maize (Zea mays L.) genotypes wit It improved nitrogen utilization efficiency (NUE) are of interest to growers. Field experiments were conducted to evaluate the total N uptake in the aboveground biomass and NUE (kg grain per kg of N absorbed in the aboveground biomass). Four commercial hybrids of similar maturity ranking were grown under the high-N (200 kg N ha(-1)) and low-N (1100 kg N ha(-1)) fertilization rates over three years. Growing conditions significantly affected hybrid performance for NUE, which ranged from 42 kg grain kg N-1 in the low-yielding (dry) environment to 55 kg grain kg N-1 under higher yielding environment, When compared to the low-N rate, the average N uptake was by 32% higher at the high-N rate, whereas smaller differences occurred for the aboveground biomass (12%), grain yields (14%), stover N (28%) and grain N (13%) concentrations. Significant differences existed among tested hybrids for grain yield, aboveground biomass, grain and stover N concentration, N uptake and consequently NUE.Hairy vetch (Vicia villosa Roth) and crimson clover (Trifolium incarnatum L.) were evaluated as cover crops during two vegetation seasons in the Mediterranean and Continental area of Croatia. Better tolerance to low winter temperatures was observed for crimson clover. Higher plants (10 to 3 1 cm) before winter and in spring (67 to 117 cm) were measured for hairy vetch, while crimson clover had higher yields of fresh biomass (33.7 to 113.1 t ha(-1)). Concentrations of N (1.53 to 3.34%), P2O5 (0.55 to 1.04%) and K2O (2.02 to 5.32%) in plant tissue were higher for hairy vetch. However, due to higher yields of dry matter, crimson clover accumulated more N (105 to 239 kg ha(-1)), P2O5 (28 to 83 kg ha(-1)), and K2O (105 to 440 kg ha(-1)) than hairy vetch. According to our results crimson clover could be recommended as a cover crop in Mediterranean and Continental area of Croatia.

Efficiency of alpha designs in Croatian variety trials

Regulations of variety trials in Croatia prescribe RCBD as the only possible trial design. This could cause many problems, especially when a large number of varieties have to be tested. In order to explore the possibilities of improving the efficiency of variety trials through the use of alternative trial design, RCBD was substituted by alpha design in a project funded by the Ministry of Agriculture and Forestry.