The phytotoxic effect of herbicides applied post-emergence was investigated in a herbicide sensitivity experiment set up on parental maize genotypes in Martonvásár. A total of 48 Martonvásár inbred lines and 12 single line crosses were included in small-plot experiments set up in two replications. Ten herbicides were applied at the normal a...uthorised rate and at twice this quantity. Compounds intended for pre-emergence application were applied when maize was in the 3–4-leaf stage and post-emergence herbicides in the 7–8-leaf stage of development. The extent of phytotoxicity was scored two weeks after treatment. Some of the herbicides tested are not authorised for use in seed production fields, but it is important to know how the parental genotypes respond to all types of herbicides. Phytotoxic symptoms of varying intensity were only observed on a third of the 60 parental genotypes examined; the majority of the lines exhibited no reaction to any of the herbicides. Averaged over the 60 genotypes the level of phytotoxic damage was less than 10% for the single dose. When the double dose was applied somewhat more severe damage was induced by products containing Mesotrione + Nicosulfuron or Foramsulfuron + Isoxadifen-ethyl, but this was still below 15%. The herbicide dose had a three times stronger influence on the intensity of the symptoms than the type of herbicide. With the exception of Topramezone, there was a significant difference between the effects of the normal and double doses. The greatest dose effect differences, in decreasing order, were observed for Mesotrione + Nicosulfuron, Foramsulfuron + Isoxadifen-ethyl. Nicosulfuron and Mesotrione + Terbutylazine. The Mesotrione + Terbutylazine active ingredient combination only caused mild (<10%) symptoms on a total of 11 genotypes, while the Mesotrione + Nicosulfuron combination induced more severe phytotoxic symptoms on 26 lines. When Nicosulfuron was applied alone it caused milder symptoms on fewer genotypes than in combination with Mesotrione. Among compounds of the sulphonyl-urea type, the least severe symptoms on the fewest genotypes were recorded in the case of Prosulfuron.
The phytotoxic effects of herbicides applied pre-, early post- and post-emergence were studied in maize in a herbicide sensitivity experiment were set up in Martonvásár and Törökszentmiklós. The herbicides were applied in normal and in double doses to 37 Martonvásár inbred lines and to six parental single crosses. The small-plot experime...nts were set up in two replications. The wet weather that followed the pre- and early post-emergence treatments promoted the appearance of phytotoxic symptoms on maize. The degree of phytotoxicity was recorded on the 14th day after post-emergence treatment and on the 14th and 28th days after the pre- and early postemergence treatments. Herbicides applied pre-emergence only caused slight symptoms on maize. Although the double dose increased the damage, it was still not more than 5% on average. The symptoms caused by herbicides applied in the early post-emergence stage were more intensive than those detected in the pre-emergence treatments. However, the damage caused by the double dose of isoxaflutol + thiencarbazone-methyl and by the split treatment with nicosulfuron remained below 10%. The symptoms became somewhat more severe at the 2nd scoring date. Among the post-emergence treatments the maize genotypes had the least tolerance of the mesotrione + nicosulfuron combination of active ingredients, where the double quantities resulted in 13–14% damage in average.
The necessity of application of hybrid specific crop production technology has been confirmed not only by trial results but also by the experiences gained from the agricultural practice. For this reason it is essential to test and collect data in field trials about the specific agronomic traits of the corn hybrids belonging to different maturit...y groups and genotypes. Corn hybrids are tested for their responses to sowing time, plant density and fertilizer supply; sensitivity to herbicides; and lately, the resistance to the damages caused by the larvae of corn root worm. Last but not least, mention should be made of the differences in the responses of the corn hybrids to the damages caused by drought stress. Based on the trial results, suggestions for the hybrid specific corn production are compiled and made public for the experts and farmers engaged in corn growing. Corn hybrids may deliver maximum yields on the impact of specific crop production technology only in case if it relies on carefully done general production technology including soil cultivation, seed bed preparation and weed control. Similarly, precision crop production technology may advance the yield increase in economic way if it is constantly drawing on the source of research results.
We did the detailed agronomy examination and assessment of sweet corn cropping technology by analysing the data of TONAVAR Ltd. The Ltd. developed a special sowing construction which is based on band application of main sowing and double growing. In main sowing they use super sweet hybrids, and in double growing they use normal sweet varieties.... In double growing sugar peas and the sweet corn can be cultivated together successfully. In every two years appearing sugar peas has a good effect on the sweet corn growing in monoculture. At the same time
the long-term successfulness of this questionable onto the illnesses of the peas because of the considerable sensitivity.
According to our examinations in main sowing the optimal period is between May 1. and 30., and in double growing the optimal period of sowing is between June 1. and 20. The optimal plant density is different too for the two sowing time. For super sweet hybrids the optimal plant number is 60-63 thousand/ha and for the normal sweet that is 65 thousand/ha.
Our examinations show that soil pest (defence with soil sterilisation in sowing time), Diabrotica virgifera, Helivoverpa armigera, Ostrinia nubialis are the greatest danger for the sweet corn quantity and quality.
The use of herbicides is the most efficient in the postemergens in main sowing and preemergens in second crop.
Our examination shows that the efficient sweet corn growing cannot be imagined without irrigation. The most efficient irrigation is in main sowing in the critical fenophase of crop time. In double growing the initial irrigation, and the crop irrigation are the most efficient. Based on the production data verifiable that beside the application of the discribed growing technology in the 2005-2007 years the average yield was 20,9t/ha of main sowing, and 17,8t/ha of second crop on chernozem soil in the Hajdúság.
In Hungary, the cocklebur species significantly endanger row crops (i.e. corn, sunflower, sugar beet). Their fast spreading is caused by many reasons: long-lasting emergence, reduced sensitivity to many kinds of herbicides, vigorous competitional ability, allelopathy, fast initial growth and changes in climate. The means of allelopathy is used...by many species of plants in the competition with one another, as well as by the cockleburs. But the efficiency of this is influenced by many factors. Species with allelopathical effect could show different behaviour under different conditions: they can produce compounds with retarding and stimulating effects in different quantities or compositions. The actual condition of the acceptor plant and the mediator agent (i.e. soil) influence the final effect.
In this experiment influence of phenology and rainfall was studied on allelopathy of cockleburs in May, July and September. A stronger inhibition was observed on growth of cress before rain in July than in May, but this retarding effect disappeared after rainfall. However, the samples collected in September have significant inhibitory effect after rain. Inhibition of sugarbeet’s germination was stronger in May than in July, and the difference increased after rain.
In Hungary, the woolly cupgrass (Eriochloa villosa [Thunb.] Kunth) endanger row crops (i.e. corn, sunflower). Its fast spreading based on some reason viz. long-lasting emergence, reduced sensitivity to many kinds of herbicides, vigorous competitional ability and fast initial growth. Allelopathy, ability of many plant species to produce one or m...ore biochemicals wgich is used tocompete with each others. In this experiment we examined, whether the woolly cupgrass possesses allelopathy, and if so, how influences on the development of cultured crops like maize, sunflower and lettuce.