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  • Author or Editor: Đ. Jocković x
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The synthetic maize population 316PO2 was subjected to genetic correlation analyses between grain yield, yield components and morphological traits. The purpose was to enable estimates to be made of the advantage of using selection indices compared with selection based on grain yield only, and if that advantage was present, to choose enough simple selection indices for practical use. Selection indices were constructed out of four traits highly significantly correlated with grain yield, in addition to yield itself. Grain yield exhibited a highly significant additive genetic correlation with ear diameter (ra=0.588**), kernels row-1 (ra=0.643**), ears plant-1 (ra=0.871**) and ear height (ra=0.427**). The most efficient index was Index No. 14 (R.E.I12345= 108.83%), which included all four traits and grain yield. Index No. 3, one of the simplest forms of index, including only ears plant-1 and grain yield, showed slightly less relative efficiency (R.E.I35=107.24%) than Index No. 14. Using this simple form of index with two characters (Index No. 3) could improve the efficiency of selection for grain yield. The estimated advantage from its use is 179.6 kg/selection cycle for grain yield over selection based only on grain yield.

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Cereal Research Communications
Authors: B. Purar, G. Bekavac, Đ. Jocković, É. Toldi Tóth, L. Kálmán, E. Raspudić, and M. Dimitrijević

Corn reddening (CR) was observed for the first time in Serbia in 1957. After that, it occurred periodically, mainly in the region of Banat. In 2002 and 2003, a severe outbreak happened in late July / early August. Initial symptoms were the occurrence of a red-violet color on the leaves, leaf sheaths, husks and the bare portion of internodes. The symptoms typically appeared at the milk maturity stage and the discoloration was the most intensive at top leaves, around the main vein and along the edges, from leaf base to tip. Soon after the occurrence of the symptoms, the affected plants wilted, the foliage dried rapidly, the red pigmentation disappeared for a greater part and finally plant died off. The ears were underdeveloped and gummous and kernels were shriveled and unfilled.Several experiments were conducted to determine a possible connection between CR occurrence and the studied factors. Corn stunt spiroplasma was not identified in the CR-affected plants, and there was no apparent relationship between CR and soil fertility or nematode species identified in soil and plant samples. Insecticide-treated plots had lower CR incidence than untreated (control) plots, indicating that biotic factors could be involved.

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Cereal Research Communications
Authors: M. Mirosavljević, V. Momčilović, P. Čanak, D. Trkulja, S. Mikić, B. Jocković, and N. Pržulj

Knowledge about the comparative development and grain filling of winter cereals under different environmental conditions is important for stable and high yielding crop production. The objective of this work was to compare patterns of grain filling in bread wheat, barley and triticale grown in the Pannonian region, as well as to investigate relationships among grain filling parameters, time to anthesis and grain yield. The trials with 12 winter cereal genotypes were carried out in four successive seasons at the location Novi Sad, Serbia. Results of this study showed that all studied grain filling parameters were significantly influenced by species, cultivar, growing season, and species by growing season interaction. Longer duration of grain filling period and period to maximum grain filling were observed in triticale and wheat cultivars compared with six and two-rowed barley. Two-rowed barley cultivars had a higher grain filling rate than other cultivars. Furthermore, a negative association between time to anthesis and grain yield indicates that cultivars with the long preanthesis period are not recommended for the agro-ecological conditions of the Pannonian plain. Generally, medium early cultivars of small grain cereals had the highest grain weight within species and spike type, suggesting that medium early cultivars have a balanced ratio of pre-anthesis and grain filling period. High values of final grain weight in different growing seasons indicate that weather conditions in the Pannonian plain are mainly suitable for grain growth.

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