النشر العلمي

  • Variability and Host Specificity of Striga hermonthica (Del.) Benth. in Response to in-situ Root Exudates of Sorghum bicolor (L.) Moench

   Striga hermonthica (Del.) Benth., Orobanchaceae, is an obligate root parasite on important cereal crops. The aim of this study is to investigate variability and host specificity in the early developmental stages of S. hermonthica parasitism in response to in-situ root exudates of sorghum. Field surveys were conducted during the seasons 2013/14 in Striga endemic areas in Sudan to collect seeds from the parasite. Fifteen S. hermonthica populations were collected. An in vivo experiment was conducted at the University of Gezira, Sudan to study the effects of in-situ root exudates of three sorghum cultivars on percentage of seed germination, haustorium initiation, attachment and penetration. 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 revealed the highest percentage of seed germination (46.9 - 57.5 %), haustorium initiation (73.8 -77.9 %), attachment (38.4 – 40 %) and penetration (20.7 – 23.7 %) into sorghum root was induced by in-situ root exudates of sorghum cv. Abu-70 and by sorghum cv. Wad Ahmed. While, the lowest percentage of seed germination (53.5 %), haustorium initiation (45.2 %), attachment (5.8 %) and penetration (1.5 %) into sorghum root was induced by in-situ root exudates of Hakika. The results also revealed that percentage of seed germination, haustorium initiation, attachment and penetration of S. hermonthica populations collected from infected sorghum in response to sorghum in-situ root exudates was the highest. While, the percentage of seed germination, haustorium initiation, attachment and penetration of S. hermonthica populations collected from infected millet in response to sorghum in-situ root exudates was the lowest. This study confirms the existence of two levels of physiological specialization in S. hermonthica populations in Sudan. Moreover, two strains of S. hermonthica are one specific to sorghum and the other to millet.

published in Journal of Research in Weed Science, 3 (2): 238-253.

  • Phytotoxic Effects of Basil (Ocimum basilicum L.) Aqueous Extract on Seed Germination of Some Cereal Crops

   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 aqueous extract of aboveground parts of basil (Ocimum basilicum L.) 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.  Laboratory experiments were carried out at the Faculty of Agricultural Sciences, University of Gezira, Sudan during the season 2017/2018. 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 aqueous extract of aboveground parts of basil were prepared from the stock solution (100 g / l). A control containing 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. Collected data were transformed using Abbott’s formula and subjected to probit analysis (P £ 0.5). The aqueous extract of aboveground parts of basil inhibited the seed germination of the tested cereal crops and there was direct positive relationship between concentration (g/l) and inhibition (%). Also, the result showed that the seeds of maize were most sensitive to the aqueous extract of aboveground parts of basil followed by the seeds of millet, wheat and sorghum. The LC50 for maize, wheat, millet and sorghum was 34.1, 46.3, 46.7, and 59.1, g/l, respectively. It was concluded that the aqueous extract of aboveground parts of basil had toxic effect to the seeds of the tested cereal crops.

published in The Libyan Journal of Agriculture, 24(2): 63-72.

  • Growth performance of two lemon [Citrus limon (L.) Osbeck] cultivars budded on three rootstocks, Gezira State, Sudan

     Lemon (Citrus limon (L.) Osbeck), family Rutaceae, is one of the world's major fruit crops with global popularity contributing to human diets. Lemon rootstocks and scion cultivars play an important role in the rapid development of citrus in the world. This study was conducted to evaluate the growth performance of two lemon cultivars budded on three rootstocks under Gezira State conditions, Sudan. The experiment was conducted in the nursery of the Department of Horticultural Sciences, Faculty of Agricultural Sciences, University of Gezira, Wad Medani, Sudan, in 2017.Volcamariana, Rough Lemon and Macrophylla rootstocks were grafted with buds of Eureka and Teresa cultivars. The T- budding technique was used in this study. Treatments were arranged in a randomized complete block design with three replicates. Parameters measured were rootstock height and thickness, height of scion, number of branches, length of branches and stem circumference of the scion. The parameters were recorded for 10 months. Data were subjected to analysis of variance procedure. Means were separated using Duncan`s Multiple Range Test.  Rootstocks were significantly different in their vegetative growth.  Rough Lemon rootstock resulted in the best vegetative growth.  However, there were no significant differences in growth parameters between Volkameriana and Macrophylla rootstocks. Lemon cultivars were highly significantly different in their vegetative performance. Teresa lemon cultivar resulted in the largest plant height (73.9 cm), number of branches (27), length of branches (68 cm) and stem circumference (11.8 cm). The interaction effects of rootstocks and cultivars on vegetative performance of lemon were significant. The largest plant height (84.33 cm), number of branches (31.7), length of branches (75.7 cm) and stem circumference (12.3 cm) were obtained by Teresa cultivar budded on Rough Lemon rootstock and the smallest parameters were obtained by Eureka cultivar budded on Volkameriana, whereas the smallest length of branches (55.3) and stem circumference (9.5 cm) were obtained by Eureka cultivar budded on Macrophylla. It is recommended to use Rough Lemon rootstock for the propagation of lemon in the Gezira State, Sudan.

published in Gezira Journal of Agricultural Sciences. 17 (2): 14-34.

  • Phytotoxic Effects of Aqueous Extracts of Apple of Sodom (Calotropis procera W.T) on Seed Germination of Ischaemum afrum (J.F.Gmel.) Dandy Using Probit Analysis

This study was carried out to investigate the phytotoxic effects of aqueous extracts of leaves, inflorescences, stems and roots of apple of Sodom (Calotropis procera W.T) on seed germination of Ischaemum afrum using probit analysis. Laboratory experiments were carried out at the Faculty of Agricultural Sciences, University of Gezira, Sudan in season 2014/15. Ten concentrations of the aqueous extract of each part of apple of Sodom were prepared by sequential dilution of the stock extract (50g/l) with sterilized-distilled water to give 2.11, 4.21, 6.34, 8.42, 10.53, 12.63, 14.13, 16.84, 18.94 and 21.05 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 procedure (P £ 0.5).The results showed that the aqueous extracts of all tested parts of apple of Sodom suppressed seed germination of the I. afrum and there was direct positive relationship between concentration (g/l) and inhibition (%). The result also revealed that the leaves aqueous extract of apple of Sodom was more toxic (LD50 = 6.3 g/l) to the seeds of I. afrum followed by aqueous extract of inflorescences (LD50 = 7.2 g/l), stems (LD50 = 11.4 g/l) and roots (LD50 = 12.7 g/l). The results indicated that the aqueous extracts of apple of Sodom had toxic effect to the seeds of the I. afrum and could offer potential for the development of alternative herbicides.

published in Agricultural and Food Science Journal of Ghana, 12: 1096-1105.

  • Allelopathic effects of Pigweed (Amaranthus viridis L.) seed on seed germination and seedling growth of some leguminous crops

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.

published in International Journal of Innovative Approaches in Agricultural Research, 3(4): 566-577.

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