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Laboratory and greenhouse experiments were carried out at the Faculty of Agricultural Sciences, University of Gezira, Sudan in season 2014/15. Laboratory experiments were conducted to study the allelopathic effects of aqueous extract of aboveground parts of pigweed [Amaranthus viridis L.] on seed germination of common bean [Phaseolus vulgaris L.], cowpea [Vigna sinensis [L.] Walp.], pigeon pea [Cajanus cajan [L.] Millsp.] and alfalfa [Medicago sativa L.]. Six concentrations [0, 20, 40, 60, 80 and 100%] of the aqueous extract of aboveground parts were prepared from the stock solution [50 g/l]. Treatments, for each crop, were arranged in completely randomized design with four replicates. The seeds were examined for germination at three days after initial germination. Greenhouse experiments were conducted to study the allelopathic effects of powder of aboveground parts of pigweed on seedling growth of the same crops. Powder of aboveground parts was incorporated into the soil at rate of 0, 1, 2, 3, 4 and 5% on w/w bases in pots. Treatments, for each crop, were arranged in completely randomized design with four replicates. Experiments were terminated at 30 days after sowing and plant height, number of leaves and root length of crop seedlings were measured as well as plant fresh and dry weight. Data were collected and subjected to analysis of variance procedure. Means were separated for significance using Duncan`s Multiple Range Test at p 0.05. The results showed that the aqueous extract of aboveground parts of pigweed significantly reduced seed germination of the tested leguminous crops and there was direct negative relationship between concentration seed germination. Also, the results showed that incorporating powder of aboveground parts into the soil significantly decreased plant height and root length of crop seedlings as well as seedling fresh and dry weight. In addition, the reduction in seedling growth was increased as the powder increased in the soil. Based on results supported by different studies, it was concluded that pigweed has allelopathic effects on seed germination and seedling growth of the leguminous crops.
Laboratory and greenhouse experiments were conducted at the Faculty of Agricultural Sciences, University of Gezira, Sudan in 2014/15 season to study the allelopathic effect of aqueous extract and powder of sodom apple [Calotropis procera L.] leaves on seed germination and seedling growth of sorghum [Sorghum bicolor [L.] Moench], millet [Pennisetum glaucum [L.] R. Br.], maize [Zea mays L.] and wheat [Triticum vulgare L.]. Treatments were arranged in completely randomized design with four replicates. Data were subjected to analysis of variance [P 0.05] and means were separated using LSD test. The results showed that the leaves aqueous extract of sodom apple significantly reduced seed germination and there was direct relationship between concentration and reduction in germination. Also, the results showed that incorporating the leaves powder into the soil at the rate of 1 - 5%, significantly, reduced plant height, number of leaves, and root length of crop seedlings as well as plant fresh and dry weight. In addition, the reduction in seedling growth was increased as the leaves powder increased in the soil. This study confirmed that the sodom apple had allelopathic effects on seed germination and seedling growth of the poaceous crops. Therefore, isolation and identification of allelochemical compounds from this plant could provide means to minimize their negative effects over the cultivated plants and potentially could provide structural models for the development of bio-herbicides.
Laboratory and greenhouse experiments were carried out at the Faculty of Agricultural Sciences, University of Gezira, Sudan in season 2014/15. Laboratory experiments were conducted to study the allelopathic effect of aqueous extract of Jimsonweed [Datura stramonium L.] seed on seed germination of common bean [Phaseolus vulgaris L.], cowpea [Vigna sinensis [L.] Walp.], pigeon pea [Cajanus cajan [L.] Millsp.] and alfalfa [Medicago sativa L.]. Six concentrations [0, 20, 40, 60, 80 and 100%] of the aqueous extract were prepared from the stock solution. Treatments, for each crop, were arranged in completely randomized design with four replicates. The seeds were examined for germination at three days after initial germination. Greenhouse experiments were conducted to study the allelopathic effect of Jimsonweed seed powder on seedling growth of the same crops. Seed powder was incorporated into the soil at rate of 0, 1, 2, 3, 4 and 5% on w/w biases in pots. Treatments, for each crop, were arranged in completely randomized design with four replicates. Experiments were terminated at 30 days after sowing and plant height, number of leaves and root length of crop seedlings were measured as well as plant fresh and dry weight. Data were collected and subjected to analysis of variance procedure. Means were separated for significance using Duncan`s Multiple Range Test at p 0.5. The results showed that the aqueous extract of Jimsonweed significantly reduced seed germination of the tested leguminous crops and there was direct negative relationship between concentration seed germination. Also, the results showed that incorporating seed powder into the soil significantly decreased plant height, root length of crop seedlings as well as seedling fresh and dry weight. In addition, the reduction in seedling growth was increased as seed powder increased in the soil. However, the number leaves did not affected. It concludes that Jimsonweed has allelopathic affects on seed germination and seedling growth of the leguminous crops.
Objective. The aim of the present study was to evaluate the efficacy and selectivity of the herbicide pendimethalin on weed control in soybean at Gezira State, Sudan. Methods. A field experiment was carried out at Gezira Research Station Farm, Wad Medani, Sudan during summer season 2018/2019. The pendimethalin [Pendimight 500 EC®] was applied at three doses as pre-emergence treatment. The doses were 1.339, 1.785 and 2.232 Kg a.i./ha. Weeded and un-wedded treatments were included for comparison. The treatments were arranged in a randomized complete block designed with four replicates. Data were subjected to descriptive analysis and analysis of variance procedure [P ≤ 0.05]. Significant means were separated using Duncan’s Multiple Range test. Results. The results showed that all herbicide treatments were effective in weed control. They significantly reduced weed infestation compared to un-weeded control and significantly promoted the yield and various growth characters of soybean over un-weeded control treatment, except pendimethalin at the dose of 2.232 Kg a.i./ha which only reduced the plant population by 7% due to a phytotoxicity effect on soybean as compared to un-weeded control treatment. Application of pendimethalin at the dose 1.339 kg a.i./ha significantly controlled grasses and broad leaf weeds in soybean. It was also found superior in respect of various growth and yield attributes. Highest seed yield [1562.5 kg /ha] was recorded under pendimethalin treatment at a dose of 1.339 kg a.i./ha. Chemical analysis of soybean seeds showed that no residues of the tested herbicide were detected. Conclusions. It is concluded that the tested pre-emergence herbicide pendimethalin at the dose of 1.339 kg a.i./ha could be used effectively and safely in controlling weeds in soybean crop.
Several plants are phytotoxic in nature as they produce and release many chemical compounds into the environment. This study was carried out to investigate the phytotoxic effects of the leaves aqueous extract of Apple of Sodom [Calotropis procera [Aiton] W.T.] on seed germination of sweet paper [Capsicum annuum L.], tomato [Lycopersicon esculentum Mill.], eggplant [Solanum melongena L.] and hot paper [Capsicum frutescens L.] using probit analysis. A laboratory experiments were carried out at the Faculty.94 and 21.05 g/l] of the leaves aqueous extract of apple of Sodom were prepared from the stock solution [50 g / l]. A control with sterilized-distilled water was included for comparison. Treatments were arranged in completely randomized design with four replicates. Inhibition of seeds germination was examined at consecutive three days after initial germination. Collected data were transformed using Abbott's formula and subjected to probit analysis procedure [P 0.5]. The leaves aqueous extract of Apple of Sodom inhibited the seed germination of tested solanaceous crops. The results displayed direct positive relationship between concentration [g/l] and inhibition [%]. Also, the result revealed that the leaves aqueous extract of Apple of Sodom was more toxic to the seeds of the hot pepper compared to the seeds of the other tested solanaceous crops. There were no differences in inhibition of seed germination among the rest of tested crops. The LC 50 for sweet pepper, tomato, eggplant and hot pepper was 14.88, 13.52, 13.46 and 5.35 g/l, respectively. It was concluded that that the leaves aqueous extract of Apple of Sodom had toxic effects to the seeds of the tested solanaceous crops.
Solanaceae plants are phytotoxic in nature as they produce and release many allelochemical compounds into the ecosystem. This study was carried out to investigate the phytotoxic effects of the seeds aqueous extract of thorn apple [Datura stramonium L.] on seed germination of common bean [Phaseolus vulgaris L.], cowpea [Vigna sinensis [L.] Walp.], pigeon pea [Cajanus cajan [L.] Millsp.] and alfalfa [Medicago sativa L.] using probit analysis. Laboratory experiments were carried out at the Faculty of Agricultural Sciences, University of Gezira, Sudan in season 2014/15. Ten concentrations [4.62, 9.26, 13.87, 18.51, 23.12, 27.74, 32.36, 36.98, 41.61 and 46.28 g/l] of the seeds aqueous extract of D. stramonium were prepared from the stock solution [100 g / l]. A control with sterilized-distilled water was included for comparison. Treatments were arranged in completely randomized design with four replicates. The seeds were examined for inhibition [%] in germination at three days after initial germination. Data were subjected to probit analysis [P 0.5]. The results showed that the seeds aqueous extract of D. stramonium inhibited the seed germination of the tested leguminous crops and there was direct positive relationship between concentration [g/l] and inhibition [%].The results also showed that the LC50 for common bean, cowpea, pigeon pea and alfalfa was 20.7, 21.9, 22.2 and 22.2 g/l, respectively. It was concluded that that the aqueous extract of thorn apple [D. stramonium L.] was phytotoxic to the seed germination of the tested leguminous crops.
Field surveys and laboratory experiments were conducted during the season 2009/10 and 2010/11 in witchweed [Striga hermonthica [Del.] Benth.] endemic areas in Sudan to investigate the host specificity of witchweed populations collected from different locations with respect seed germination and haustorium initiation in response to sorghum root exudates and extracts. Field surveys were conducted to collect seeds from witchweed plants growing under their respective hosts; sorghum and millet. A total of fifteen witchweed populations were collected. Tow in vitro experiments were conducted at the Phytopathology Center and Biology Laboratory, Faculty of Agricultural Sciences, University of Gezira, Sudan to study the effects of root exudates and root extracts of sorghum cv. Abu-70, cv. Wad Ahmed and cv. Hakika on percentage of seed germination and haustorium initiation. Treatments [fifteen witchweed populations and three sorghum cultivars] were arranged in a factorial completely randomized design with three replicates. Data were collected and subjected to analysis of variance. Means were separated for significant using Duncan's Multiple Range Test [at p 0.5]. The results showed that, there were significant differences in seed germination and haustorium initiation of witchweed in response to root exudates and root extracts among sorghum cultivars and among the witchweed populations. However, the highest seed germination and haustorium initiation percentages attained by each of the witchweed population were on their respective hosts. This study suggests two levels of physiological specialization in witchweed in Sudan: intercrop specialization and intra-crop specialization. Moreover, two strains of witchweed are suggested, one specific to sorghum and the other, to millet. The existence of variability and host specificity within witchweed populations are suggested to be based almost entirely on differential response of Striga isolates to root exudates and root extracts from host.
Several agro-forestry trees may have the ability to retard germination and growth of other plants by releasing many chemical substances into the environment. This study was carried out investigate the phytotoxic effects of the leaves aqueous extract of Eucalyptus camaldulensis Dehnh on seed germination of sorghum [Sorghum bicolor [L.] Moench], millet [Pennisetum glaucum [L.] R. Br.], maize [Zea mays L.] and wheat [Triticum vulgare L.] using probit analysis. A laboratory experiments were carried out at the Faculty of Agricultural Sciences, University of Gezira, Sudan in season 2014/15. Ten concentrations [4.44, 8.89, 13.33, 17.78, 22.22, 26.66, 31.11, 35.55, 40.00 and 44.44 g/l] of the leaves aqueous extract of Eucalyptus were prepared from the stock solution [100 g / l]. A control with sterilized-distilled water was included for comparison. Treatments were arranged in a completely randomized design with four replicates. The seeds were examined for inhibition [%] in germination at three days after initial germination. Collected data were transformed using Abbott's formula and subjected to probit analysis procedure [P 0.5]. The results revealed that the leaves aqueous extract of Eucalyptus inhibited the seed germination of the tested cereal crops and there was a direct positive relationship between concentration [g/l] and inhibition [%].The results also revealed that the seeds of wheat were most sensitive [LC50 = 18.7 g/l] to the leaves aqueous extract of Eucalyptus followed by the seeds of sorghum [LC50 = 21.3 g/l]. However, the extract was less toxic to the seeds of millet [24.1 g/l] and maize [25.9 g/l]. It was concluded that the leaves aqueous extract of Eucalyptus had a toxic effect on the seeds of the tested cereal crops.
Witchweed [Striga hermonthica [Del.] Benth.] is obligate root-parasitic plants belonging to the Orobanchaceae family are deadly pests for major crops all over the world. The aim of this study is to investigate host specificity of Sudan witchweed [S. hermonthica] seed germination and haustorium initiation in response to millet [Pennisetum glaucum [L.] R. Br.] root exudates and extracts. Field surveys were conducted during the seasons 2013/2014 in Striga endemic areas in Sudan to collect seeds from the parasite. Fifteen S. hermonthica populations were collected. Tow in vitro experiments were conducted at the University of Gezira, Sudan to study the effects of root exudates and root extracts of millet cv. Ugandi, cv. Ashana and cv. Sudan II on percentage of seed germination and haustorium initiation. Treatments were arranged in a factorial completely randomized design with three replicates. Data were subjected to the analysis of variance [P 0.5]. The results showed that there were significant differences in seed germination and haustorium initiation of witchweed in response to root exudates and root extracts among millet cultivars and among the witchweed populations. Moreover, the highest seed germination [61.7-76.4 %] and haustorium initiation [55-58%] percentages attained by S. hermonthica collected from parasitized millet. While the lowest seed germination [35.3-37.1%] and haustorium initiation [14.3-17%] percentages attained by S. hermonthica collected from parasitized sorghum. This study confirms the existence of two levels of physiological specialization in S. hermonthica populations in Sudan. Moreover, two strains of S. hermonthica are suggested, one specific to sorghum and the other to millet. The existence of host specificity within witchweed populations are suggested to be based almost entirely on differential response of Striga isolates to root exudates and root extracts from the host.
Laboratory and greenhouse experiments were carried out at the Faculty of Agricultural Sciences, University of Gezira, Sudan in season 2014/15 to study the allelopathic effects of Jimsonweed [Datura stramonium L.] seed on seed germination and seedling growth of some poaceous crops. Laboratory experiments were conducted to study the allelopathic effects of aqueous extract of Jimsonweed [Datura stramonium L.] seed on seed germination of sorghum [Sorghum bicolor [L.] Moench], millet [Pennisetum glaucum [L.] R. Br.], maize [Zea mays L.] and wheat [Triticum vulgare L.]. Six concentrations [0, 20, 40, 60, 80 and 100%] of the aqueous extract of Jimsonweed seed were prepared from the stock solution [50 g / l]. Treatments, for each crop, were arranged in completely randomized design with four replicates. The seeds were examined for germination at three days after initial germination. Greenhouse experiments were conducted to study the allelopathic effects of Jimsonweed seed powder on seedling growth of the same poaceous crops. The seed powder was incorporated into the soil at rate of 0, 1, 2, 3, 4 and 5% on w/w bases in pots. Treatments, for each crop, were arranged in completely randomized design with four replicates. The experiments were terminated at 30 days after sowing and the plant height, number of leaves and root length of crop seedlings were measured as well as plant fresh and dry weight. Data were subjected to analysis of variance procedure. Means were separated for significance using Duncan`s Multiple Range Test at p 0.5. The results showed that the aqueous extract significantly reduced seed germination of the tested poaceous crops and there was direct negative relationship between concentration seed germination. Also, the results showed that incorporating seed powder into the soil significantly decreased plant height, number of leaves and root length of crop seedlings as well as seedling fresh and dry weight. In addition, the reduction in seedling growth was increased as seed powder increased in the soil. It concludes that Jimsonweed has allelopathic effects on seed germination and seedling growth of the poaceous crops.