Milomirka Madic

Sowing density and nitrogen fertilization influences on yield components of barley

Introduction The yield and quality of spring malting barley have a high degree of variability depending on both weather and soil conditions and applied soil and crop management. Adequate sowing density and nitrogen (N) applications by top dressing are important factors of barley growing and their optimal values are mainly associated with hereditary and environmental factors (Maksimovic et al., 1996; Paunovic, 2001; Lalic et al., 2006; Kovacevic et al., 2006). The ear number is the most important yield component of small grains. The tendency of barley to stalk lodging is an additional problem of N application by top-dressing. The aim of this study was to test the effects of sowing densities and N fertilization on yield components of five commercial spring malting barley cultivars under environmental conditions of central Serbia (Sumadija region).

Combining abilities for spike traits in a diallel cross of barley.

Five two-row winter barley (Hordeum vulgare L.) cultivars divergent in spike traits were crossed in all possible combinations excluding reciprocals to produce 10 F1 and F2 hybrids for analysis of combining abilities. The analysis of variance of combining abilities showed significant differences for GCA and SCA in F1 hybrids and F2 generation, suggesting additive and non-additive gene action. The GCA/SCA ratio in F1 and F2 indicated the prevalence of the additive component of genetic variance for spike length, grain weight per spike and spike harvest index. By contrast, the SCA variance for grain weight per spike was higher than the GCA variance, indicating the dominance of non-additive gene action. Good GCAs were found in parents having high values for spike length (Djerdap, NS-293), grain number per spike (Vada, Jagodinac), grain weight per spike (Vada, NS-293) and spike harvest index (Djerdap, Jagodinac). None of the parents had good GCA for all traits, suggesting a potential increase in combining abilities for spike traits. The best SCA were obtained mostly from crosses between parents having high x low, high x high or average x low GCA values. Parents having high GCA values may be used to produce improved lines in hybridisation programmes. Combinations with high SCA values may yield good segregating lines in further selection programmes.

Alternative Cereals in Carp (Cyprinus carpio L.) Nutrition

Summary Due to their high carbohydrate content, cereals are the main source of energy in human, livestock and fish diets, with wheat and maize being the most commonly used crops. Although these two crops, along with rice, satisfy about 50% of human energy requirements, it is necessary to introduce other crops, which are of minor commercial importance. This necessity has been intensified by the growing needs of aquaculture, particularly with respect to carbohydrate requirements. Cereal grains account for an average of 35-45% of the feed ration for common carp (Cyprinus carpio). Experiments have been conducted on the use of barley, triticale and rye as substitutes for wheat and maize. The grains of these replacement cereals are preliminarily subjected to gelatinisation due to the high content of crude starch. Results indicate the possibility of partial or complete substitution (for maize) in some fish feeds. The usability (feed value) of cereals in fish nutrition is ranked in the order: wheat > triticale > maize > barley > rye.

Boron application in red clover (Trifolium pratense L.) seed production

Abstract A field trial with four red clover cultivars was established on acid soil in order to evaluate the effect of foliar boron application on seed yield. The crop received foliar boron treatment during the second growth of the second year at two applications. Although seed yield showed a significant increase in boron-treated plants in 2011 compared with control (26.0%), its relative increase was far higher in 2010 (43.2%), which had increased total rainfall amounts during flowering. Sufficient level of boron supply to red clover plants for seed production has a remarkably positive effect under conditions hampering pollination and fertilisation.

Stability Parameters for Grain Yield and its Component Traits in Maize Hybrids of Different FAO Maturity Groups

An objective evaluation of maize hybrids in intensive cropping systems requires identification not only of yield components and other agronomically important traits but also of stability parameters. Grain yield and its components were assessed in 11 maize hybrids with different lengths of growing season (FAO 300-700 maturity groups) using analysis of variance and regression analysis at three different locations in Western Serbia. The test hybrids and locations showed significant differences in grain yield, grain moisture content at maturity, 1,000-kernel weight and ear length. A significant interaction was observed between all traits and the environment. The hybrids with higher mean values of the traits, regardless of maturity group, generally exhibited sensitivity i.e. adaptation to more favourable environmental conditions as compared to those having lower mean values. Regression coefficient (bi) values for grain yield mostly suggested no significant differences relative to the mean. The medium-season hybrid gave high yields and less favourable values of stability parameters at most locations and in most years, as compared to mediumlate hybrids. As compared to medium-early hybrids, medium-late hybrids (FAO 600 and 700) mostly exhibited unfavourable values of stability parameters i.e. a specific response and better adaptation to favourable environmental conditions, and gave higher average yields. Apart from producing lower average yields, FAO 300 and 400 hybrids showed higher yield stability as compared to the other hybrids tested. Medium-late hybrids had higher yields and showed a better response to favourable environmental conditions compared to early-maturing hybrids. Therefore, they can be recommended for intensive cultural practices and low-stress environments. Due to their more favourable stability parameter values, medium-early hybrids can be recommended for low-intensity cultural practices and stressful environments.