Vlado Guberac

Maize and soybean seed vigour under influence of seed age, seed treatment and temperature in cold stress test

Maize and soybean seed (maize hybrid OS 499 and soybean cultivar Ika originated from Agricultural Institute in Osijek, Croatia) harvested in year 2006 as well as one year old seed (harvested in 2005 and aged in storehouse conditions) were used for the evaluation of seed vigour in germination chamber. Seeds were pretreated with fungicide. Fungicide treatment significantly increased germination rate of maize seed in cold test conditions and constant low temperature. Fungicide treatment of soybean seed significantly enhanced germination only at constant low temperature and aged seed. Biostimulant applicaton did not enhanced germination rate but increased dry matter content in normally developed hypocotyls, both in fresh and aged soybean seed. Proline treatment did not show expected stimulative effect on seed germination.

Environmental effects on grain yield and malting quality parameters of winter barley

Conducted researches showed significant effect of cultivar and environment on grain yield and malting quality of barley. Barun is cultivar with the highest grain yield and very good indicators of protein and malt extract content. Vanessa had lower grain yield than cultivars Barun and Zlatko, higher protein content in grain but the best indicators of malt extract, malt viscosity and beta-glucan. Cluster analysis of malt extract content indicated grouping of locations Nova Gradiska and Pozega as well as Osijek and Tovarnik, which did not depend on year. Significant differences were found for beta glucan content between years and locations of testing, and particularly inadequate beta glucan content was found at Osijek and Nova Gradiska locations in 2005. Interactions of variety and environment may have an impact on sustainable cropping methods.

Performance of different eruca acid type oil seed rape cultivars in a Croatian agro-environment

A constant need for energy is necessary and permanent as far as our modern society is concerned. Today we have a large number of projects and studies of different alternative energy resources. Among them the most interesting are biofuels. Due to climatic conditions Europe has decided in favour of the oil production for biodiesel fuel with oil seed rape as the most appropriate culture due to the way of its cultivation as well as the way of fuel production. The aim of these researches was to investigate the economic and other characteristics of the “ 00” European oil seed rape cultivars in the Croatian agroenvironmental conditions and based on the results to introduce the most perspective ones into production.

Grain yield of new Croatian winter wheat cultivars in correlation with sowing rate

The aim of this research was to examine influence of sowing rate on grain yield of four new winter wheat cultivars, taking in account their genetic characters. Statistical analysis of the obtained results showed that the sowing rate influence on the grain yield was not statistically significant. On the other hand, various sowing rates had highly significant influence on the ear number per a unit area. The largest number of ears was achieved by the sowing rate of 700 germinable seeds/m 2 (794.8 ears/m 2 ).Difference in grain yield between examined cultivars was highly significant (P<0.01) while the difference in number of ears per a unit area was significant (P<0.05). The highest average yield and highest number of ears in the two-year period were achieved by the cultivar AG 5.12 (8.56 t/ha and 770 ears/m 2 ).Since a satisfactory and statistically significant grain yield was achieved, even with a lower sowing rate, both during and in the average of the two year research, the author’s advice wheat producers...

The effect of water stress on some traits of winter barley cultivars during early stages of plant growth

We conducted research of exposing barley plants to short water stress deficiency through their early growth stage. The measurements and parallel analyses of relative water content (RWC), the mass of the whole plant, leaf mass, root percentage, total root length and length of root fractions with plants exposed to stress (water deficit) and with plants which were not exposed to water deficit have been conducted. Ten varieties were included in this research. The overall average of relative water content (RWC) measured in winter barley varieties 97.5% under non-stressful conditions, and 66.1% under stressful conditions. An average difference between non-stressful and stressful conditions of plant mass was 61.2 mg, leaf mass 42.5 mg, RWC 31.4%, root mass 18.5 mg and total root length 129 cm. Relative losses under effect of water stress were lower at smaller (finer) root fractions. Significant differences among the examined barley varieties cultivated under or without the water stress were found for plant mass, leaf mass, root mass, total root length and root fractions. Varieties with the lowest losses in leaf and plant mass are Titan, Arturio and Bingo. Also, the varieties Titan, Bingo and Rex had the lowest losses of root length and mass during early growth stage.

Spring Barley Genotypes Traits Regarding Genotype : Environment Interaction to Croatian Environments

One of the biggest challenges for the safe maize production is the yield stability in a wide range of environments with different soil fertility, weather conditions, prevailing pests and diseases as well as cultural practices. In order to achieve it, new hybrids with higher tolerance to biotic and abiotic stress are continuously being created. In order to compare performance of maize hybrids in environments with different levels and types of stress, and relate it to the stalk lodging incidence, we compared performance of 64 maize hybrids obtained by crossing 16 inbred lines with four inbred testers in three different environments. Two environments at same location (Rugvica) differed in crop rotation, and the third environment at location Botinec was considered as dry because of low water capacity of the soil. Mixed models that included all design elements and genetic background of hybrids were used to analyze the effect of lodging on yield in different environments. The results show that stalk lodging had a significant effect on yield, but significant lodging x environment interaction indicates that this effect was rather environment specific.Sweet pepper Istra F1 hybrid was grown in a greenhouse on K rich soil. For evaluation of K antagonism, two K rates (55 and 85 kg ha-1) were applied in a randomized complete block design with four replications. Total number of fruits, total number of BER affected fruits as well as average fruit mass were recorded for each harvest. Fruit and leaf K and Ca content were determined at three plant growth stages (at the stage of the first, third and fifth fruit cluster). Higher K rate gave higher : average fruit mass (169.45 g), total number of fruits per plant (7.95), number of BER affected fruits per plant (3.82), K in leaves (5.44% DM), K in fruits (6.35% DM), but negatively correlated with Ca concentration in fruits (0.57% DM) and leaves (3.24% DM). This resulted in decreased marketable yield of sweet pepper fruits.

The influence of mycorrhizae on pea yield and quality in drought caused stress conditions

Mycorrhizas are associates of fungi, representatives of Zygomyceta, Basidiomyceta and Ascomyceta living on the higher plant roots. Mycorrhizal fungi fossil residues were found on the roots of the first vascular plants derived from the Devon period approx. 400 mil. years B. C. Botanists think that this symbiotic association played an essential role in developing and spreading vascular plants on the earth. However, regardless of their effect on vascular plants development of mycorrhizal fungi affected soil development. They produce humous components and an organic sticky substance (extra-cellular polysaharides) that hold soil into aggregates resulting in a well structured soil of good porosity and a large mycorrhizas intake in the total microbial bio-mass. These fungi colonize roots in about 90% of the vascular plants. The symbiotic association between higher plants and mycorrhizal fungi is highly-interrelated whereby plants benefit from their symbiont whereas fungi gets photosynthesis-formed carbon compounds. Owing to a dense hyphas network that interweaves large soil volume, an effective root absorption zone increases via hyphas. However, the mycorrhizal fungi also extracts chemical agents, thereby, making available elements such as phosphorus, iron, zinc, copper, boron, otherwise presented in low concentrations in a soluble form. Mycorrhizas produce antibiotics protecting plants from parasitic fungi and nematodes whereas owing to hypha network around a root, a plant is protected against parasites. Mycorrhized plants are more resistant to a drought-caused stress, have better and more adequate root system and vascular tissue development. Due to the aforesaid, dry conditions are characterized by plants having higher survival percent and higher yield elements compared to non-mycorrhized ones. Thanks to the traits of this symbiosis and all benefits possessed by mycorrhized plants compared to non-mycorrhized, an agricultural production does not rely only on the indigenous strains of these fungi but inoculation of seedling seed and root is done by a compatible strain of mycorrhizal fungi. Inoculation is done by a dry treatment or wet one in a way that the inoculum suspended is water prior to inoculation (similar to legume seed inoculation with bio-preparations of the nodule bacteria). This procedure is capable for ensuring effective symbiosis and reducing mineral fertilizer and pesticide requirements being very important from economical and ecological aspect.

The influence of oilseed rape ripening on the drying process in a dryer

Drying is the oldest but also the most simple way of preservation. Grains are dried to the level of moisture equilibrium. It is well known that different parts of oilseed rape seeds, that have different initial moisture levels, behave in a different way during drying. Bristol, Eurol, and Alaska, which are „ 00” rapeseed cultivars were researched. Bristol and Alaska are French sorts produced by Monsanto S.A.S. Alaska is a German sort produced by KWS. The research was conducted on fields in Zdenci.The mean bootstrap value (“ bootstrap mean” ) of the correlation coefficient was 0.657 ; the bias was 0.00736 ; the standard failure (bootstrap estimation of standard failure) was 0.247 ; a normal 90% bootstrap interval of the correlation coefficient ranged from 0.23589 to 1.00. The real (population) correlation coefficient was higher than zero, i.e. there was a positive correlation between the length of time of the ripening in field and drying in a dryer. A linear regression model, which best describes the linear relation between the length of time of the ripening in field and the length of time of drying in a dryer can be expressed as y =1, 47564 x – 6, 6605. The mean bootstrap regression coefficient value was 1.5024 ; the bias 0.0267 ; the standard failure was 0.7401 ; a normal 90% bootstrap interval of the correlation coefficient ranged from 0.232 to 2.666. The real (population)correlation coefficient was higher than zero, i.e. there was a positive correlation between the length of the ripening in field and the drying in a dryer.