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Összefoglalás

A köztermesztésben szereplő korszerű napraforgó hibridek termésbiztonságának fokozása az agrotechnikai tényezők optimalizálását teszi szükségessé. A vetéstechnológia jelentős mértékben képes kompenzálni az évjárat kedvezőtlen hatásait, valamint hozzájárulni a kórokozókkal szembeni sikeresebb védekezéshez és a termésmaximalizáláshoz. A tőszám és a vetésidő az agrotechnika két sarkalatos pontját képezi. A kísérletet a hajdúsági löszháton állítottuk be a 2009. évben. A köztermesztésben alkalmazott napraforgó hibridek tőszám és vetésidő reakcióját vizsgáltuk a kórtani tényezők és a produktivitás vonatkozásában. Az eltérő időpontú vetésidők a szárszilárdsági paramétereket, valamint a betegségfertőzöttséget jelentősen befolyásolták. A legkésőbbi időpontú vetésidőben volt a szárdőlés és a tányér alatti szártörés mértéke a hibridek átlagában a legalacsonyabb (4,6%, 1,9%), míg a korai vetésidőben a legmagasabb (9,5%, 6,3%). Ugyanez a tendencia érvényesült a szár Sclerotinia, a Diaporte, valamint a tányérbetegségek fertőzöttségével kapcsolatban is. A tőszám növelése ugyancsak a szárszilárdsági paraméterek romlásához, valamint a vizsgált kórokozók infekciójának növekedéséhez vezetett. A 2009. száraz évjáratban az 55 000 tő ha−1 állománysűrűség bizonyult optimálisnak (4838 kg/ha). A 2009. évben az április közepi vetésidőben kaptuk a hibridek átlagában a maximális termést (4717 kg/ha). A korábbi vagy későbbi vetésidő egyaránt terméscsökkenéshez vezetett (3712 kg/ha, 4228 kg/ha). A kórokozók kártétele a vetésidő későbbre halasztásával fokozatosan csökkent. A hibridek olajtartalmát a vetésidő és az állománysűrűség befolyásolta. A legnagyobb átlagos olajtartalmat a 3. vetésidőben (44,51%), valamint a legnagyobb vizsgált tőszámsűrűségi szinten figyeltük meg (44,27%). Az olajhozam alakulását elsősorban a termésmennyiség határozta meg. A hibridek genotípusosan eltérő módon reagáltak a kísérlet során mind a tőszám, mind a vetésidő változására a vizsgált tényezőkkel kapcsolatban.

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Összefoglalás

Tartamkísérletben, csernozjom talajon, a Hajdúságban (Kelet-Magyarország) vizsgáltuk néhány agrotechnikai tényező (tőszám, tápanyagellátás), néhány kártevő és kórokozó (kukorica bogár (Diabrotica virgifera virgifera LeConte), kukoricamoly (Ostrinia nubilalis Hbn.), csőfuzárium (Fusarium spp.), valamint az évjárat (eltérő vízellátottságú évek: 2007. év = aszályos, 2008. év = kedvező) hatását a kukorica termésére különböző vetésváltási rendszerekben (mono-, bi- és trikultúra). A vizsgálatokat nem öntözött körülmények között, csernozjom talajon végeztük. Vizsgálati eredményeink azt bizonyították, hogy az évjárat vízellátottsága, mint abiotikus stressz tényező volt a legnagyobb hatással a kukorica termésére, valamint meghatározta az optimális tőszámot és trágyaadagot. Aszályos évjáratban (2007. év) a kukorica termésmaximuma 3874–5681 kg/ha (mono), 7156–7929 kg/ha (bi), 7214–8192 kg/ha (tri), kedvező vízellátottságú évben pedig 12 902–13 787 kg/ha (mono), 13 974–14 603 kg/ha (bi) és 13 594–14 839 kg/ha (tri) intervallumban mozgott nem öntözött feltételek között. Az ökológiai stressz (vízhiány) okozta terméscsökkenés monokultúrában 9,0 t/ha, bikultúrában 7,0 t/ha, trikultúrában pedig 6,0 t/ha körül változott. A kukorica optimális tőszámát és trágyaadagját mind az ökológiai stressz (vízhiány), mind az agrotechnikai stresszhatás (vetésváltás) befolyásolta. Aszályos évjáratban (2007. év) a 40 ezer/ha (mono, bi, tri), kedvező vízellátottságú évjáratban a 60 ezer/ha (mono) és 80 ezer/ha (bi és tri) tőszám esetében kaptuk a termésmaximumokat. Az évjárat és a vetésváltás egyaránt módosította az optimális trágyaadagot. A 2007. év időjárása miatt a növényegészségügyi értékek kedvező szinten mozogtak, a csőfuzárium-fertőzöttség 0,9–3,4%, a molyfertőzöttség 2,1–4,5% között változott, míg a kukoricabogár által okozott növénydőlést nem tapasztaltunk. Ezzel szemben a csapadékos évjáratban a csőfuzárium-fertőzötség értéke 1,0–3,9%, a molykártétel értéke pedig 3,2–6,3% között alakult. 2008-ban monokultúrában jelentős kukoricabogár kártételt is tapasztaltunk. A Diabrotica által okozott növénydőlés (12,3–62,2%) között változott, kezelésektől függően.

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Genetic variability and correlation analysis were studied in 20 accessions of ‘egusi’ melon during two growing seasons. The genotypic correlation coefficients with seed yield were partitioned into direct and indirect effect causes. Heritability in the broad sense ranged from 17% for fruit circumference to 90% for days to germination and flowering in the early season, while in the late season, heritability ranged from 7% for seed weight per fruit to 88% for days to germination. High phenotypic and genotypic coefficients of variation were recorded for seed yield while days to maturity had the lowest in both seasons. Fruit circumference and fruit weight had significant genotypic and phenotypic correlation with seed yield in the early season, while number of branches per plant, vine length per plant, number of fruits per plant and fruit circumference per plant showed significant genotypic and phenotypic correlation with seed yield in the late season. Environmental correlation coefficients were significant between seed yield and vine length per plant, number of fruits per plant and fruit size per plant. Vine length per plant and fruit circumference per plant had the largest positive direct effect on seed yield. Knowledge of the relationship of these characters with seed yield will aid in the selection of genotypes that have high seed yield, which will also be specific to the two major seasons in the year.

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The space available to plants affects the available resources and hence modifies the growth habits and yield potential of plants. The effect of four seeding densities (250, 500, 750 and 1000 viable seeds/m2) and three row spacings (12, 15 and 20 cm) were evaluated at Morfa Mawr field station at the University of Wales, Aberystwyth, UK during the 1993 and 1994 growing seasons. Number of capsules per plant, number of seeds per capsule, thousand-seed weight and seed yield were examined during the study. Capsule index (CI) and harvest index (HI) were calculated from the observed data. During the first year, capsules per plant, seeds per capsule and capsule index were increased by decreasing the seed density, while the maximum seed yield of 3.9 t/ha was recorded at the highest seed density of 1000 seeds/m2. An increase in row spacing led to an almost linear increase in most of the yield attributes of the crop. During the second year, the response of yield and yield attributes to seeding densities was similar to that recorded during the first year. Seed yield increased with decreasing row spacing, while the rest of the components did not show any consistent response. During the first year, the overall performance and production of the crop was higher than in the second year because of the better weather conditions, with mild temperature and high rainfall during the season.

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This research was carried out in the Experimental Field of Tekirda đ Agricultural Faculty. Two common vetch varieties and 5 lines were sown with 150 seeds/m 2 plant density according to a randomised block design. Some important yield related characters such as plant height, number of branches, number of pods per plant, number of seeds per pod, pod width, pod length, 1000 seed weight, fodder and seed yield were examined. The results of variance analysis showed that the effects of genotype, year and their interaction on number of branches and number of pods per plant were all significant. In addition, the effect of year and variety on plant height and seed yield were found to be significant. Moreover, the number of seeds per pod, pod width and pod length were found to be significant in variety and year × variety interaction. There was only a difference between years for 1000 seed weight and fodder yield. According to the results, genotype 283 and Tokat had similar performance to that of commercial cultivars (Ürem, Kubilay). Especially the fodder and seed yield of genotype 283 were found to be higher than those of the cultivars (Ürem, Kubilay).

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Fifteen onion genotypes (one standard check and 14 exotic cultivars) were evaluated in RCBD with 3 replications at Melkassa Research Center during the 1999/2000 growing season (Aug.–Feb.). The objective of the study was to understand the association of characters with seed yield. The genotypic correlation coefficients were greater in magnitude than the phenotypic ones. Seed yield/plant had a high, significant correlation with number of flower stalks/plant, number of seeds and flowers/umbel and umbel size. Bolting and flowering period had a significant negative correlation with seed yield/plant. From the path analysis results, the number of flower stalks/plant, bolting period, thousand seed weight, flower stalk diameter and umbel size had a high direct positive effect on seed yield/plant. Since the direct and indirect effects through these components on seed yield are high and positive, selection should concentrate on these traits for high seed yield in onion cultivars. Since these components were found to affect seed yield they could be used for developing varieties for the growing onion industry in the country.

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Wheat is an important source of staple food and has a major role at human nutrition and it is essential to know the relationships between yield and its components in wheat breeding programs. In the examined characteristics, positive and the expression significant correlation were found statistically between the flag leaf area, germination in mannitol, survival after desiccation and number of tillers per plant with grain yield. Negative and significant relationships were determined statistically between the plant height, water loss of excised leaves, root length and root depth with grain yield. Path coefficient revealed that number of tillers per plant (9.166) and root depth (0.2675) had the highest positive direct effects on grain yield. In addition water loss of excised leaves (−9.057) and survival after desiccation (−0.449) have highest negative direct effect on grain yield. The improvement in grain yield will be efficient if the selection is based on the number of tillers per plant, root depth and flag leaf area under drought conditions. Comparatively high genetic variability was found in grain yield, flag leaf area and tillers per plant. Number of tillers per plant had direct and marked effect and majority of the traits affected grain yield through it.

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The botanical composition of grasslands determines the agronomic and natural values of swards. Good grassland management usually improves herbage value, but on the other hand it frequently decreases the plant diversity and species richness in the swards. In 1999 a field trial in a split-plot design with four replicates was therefore established on the Arrhenatherion type of vegetation in Ljubljana marsh meadows in order to investigate this relationship. Cutting regimes (2 cuts — with normal and delayed first cut, 3 cuts and 4 cuts per year) were allocated to the main plots and fertiliser treatments (zero fertiliser — control, PK and NPK with 2 or 3 N rates) were allocated to the sub-plots. The results at the 1 st cutting in the 5 th trial year were as follows: Fertilising either with PK or NPK had no significant negative effect on plant diversity in any of the cutting regimes. In most treatments the plant number even increased slightly compared to the control. On average, 20 species were listed on both unfertilised and fertilised swards. At this low to moderate level of exploitation intensity, the increased number of cuts had no significant negative effect on plant diversity either (19 species at 2 cuts vs. 20 species at 3 or 4 cuts). PK fertilisation increased the proportion of legumes in the herbage in the case of 2 or 3 cuts. The proportion of grasses in the herbage increased in all the fertilisation treatments with an increased numbers of cuts. Fertiliser treatment considerably reduced the proportion of marsh horsetail ( Equisetum palustre ) in the herbage of the meadows. This effect was even more pronounced at higher cut numbers. The proportion of Equisetum palustre in the herbage was the highest in the unfertilised sward with 2 cuts (26.4 %) and the lowest in the NPK-fertilised sward with 4 cuts (1.4%).

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Received: 14 February, 2000; accepted: 29 August, 2000 In this research, three bread wheat varieties were sown at six different plant densities in the experimental field of Tekirda đ Agricultural Faculty according to a split-plot randomised block design. A range of characters such as number of tillers per plant, number of spikes per plant, grain weight of tillers per plant, plant height, harvest index, plant yield and grain yield per hectare were investigated. The results of variance analysis showed that the effects of sowing rate and variety and their interaction on number of tillers per plant, plant height and grain yield per hectare were all significant. In addition, the effect of plant density on grain weight per tillers, grain yield per plant and number of spikes per plant was significant, whereas the effect of variety was only significant on harvest index. It was found that the number of fertile tillers per plant was the most suitable character as a selection criterion for improving grain yield in the Thrace Region. According to path analysis the direct and indirect effects of the measured characters on grain yield per plant and grain yield per hectare showed that the number of spikes per plant, harvest index, grain weight of tillers per plant and plant height had a direct positive effect on grain yield per plant. However, the number of spikes per plant and the number of tillers per plant had a negative effect on grain yield per hectare, while the harvest index and grain yield per plant had a positive direct effect.

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Two field experiments were carried out at the Experimental Farm of Assiut University, during the 2000 and 2001 summer seasons, to study the effect of three hill spacings (5, 10 and 15 cm) and six weed control treatments on the associated weeds, plant growth, yield and quality of soybean. The weed control treatments were carried out with trifluralin, linuron, pendimethalin, bentazon and hand hoeing, with an unweeded treatment as the control. All the weed control treatments exerted a significant influence on the dry weight of weeds. Hand hoeing and pendimethalin treatment significantly decreased the dry weight of dicot and monocot weeds as compared to the unweeded treatment. Hand hoeing gave the lowest value of the dry weight of total weeds and the highest efficiency percentage. In general, the significantly lowest dry weight of total weeds was recorded for densely sown soybeans. The weed control treatments exerted a significant influence on all the characters under study (plant height, weight of pods and seeds/plant, number of plants at harvest, seed yield/ha). The height of the first pod was lowered by hand hoeing and the application of pendimethalin increased the number of pods/plant, while the highest values of number of branches/plant, seed index, oil and protein contents were obtained after linuron application. wider spacing produced higher values for the number of pods and branches/plant, weight of pods and seeds/plant, seed index and protein content and lowered the height of the first pod as compared to plants sown at closer spacing. The latter produced the highest values of number of plants/ha, seed yield/ha and oil content at harvest. The first order interaction exerted a significant influence on all the characters studied, the highest seed yield/ha (2728.6 kg) being obtained from sowing plants at 5 cm combined with hand hoeing.

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