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A new bacterial strain, capable of degrading poly(3-hydroxybutyrate) (PHB) was isolated from soil. This organism, identified as Streptoverticillium kashmirense AF1, secreted PHB depolymerases both on solid as well as in liquid mineral salt medium containing poly(3-hydroxybutyrate) as sole carbon source. The optimum production of PHB depolymerase was observed at pH 8 and 7, at 45 °C, 1% substrate concentration and in the presence of lactose as an additional carbon source. The extracellular PHB depolymerase was purified by gel permeation chromatography using Sephadex G-75. The Streptoverticillium kashmirense AF1 produced two types of PHB depolymerases having molecular weights of about 37 and 45 kDa as determined by SDS-PAGE. The difference in dry cell mass and amount of CO 2 evolved in the test and control calculated gravimetrically through Sturm test indicated the degradative capabilities of Streptoverticillium kashmirense AF1.

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A pot culture experiment was conducted to study the influence of NH 4 Cl (AnalaR grade or commercial fertilizer) on soil pH and on the growth, yield and nutrient uptake of cotton (cv. NIAB-Karishma) grown in alkaline soil. The experiment was carried out in a net-house under natural conditions. The soil used was clayey loam with pH 8.61, and ammonium chloride either from commercial fertilizer or of AnalaR grade (both containing up to 25% N) was applied in three split doses, after germination (10 days), at the vegetative stage (40 days) and at the flowering stage (80 days) @ 6, 12 and 18 kg ha −1 . The application of NH 4 Cl decreased the soil pH and increased the plant height and cotton yield plant −1 . Plants treated with NH 4 Cl AnalaR grade produced higher yields as compared to NH 4 Cl commercial fertilizer. The uptake of micronutrients such as Fe, Cu, Zn and B was enhanced by NH 4 Cl application in both the stem and leaves of cotton. However, AnalaR grade NH 4 Cl proved more effective than NH 4 Cl commercial fertilizer in all cases.

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The objective of this study was to develop a simple anther culture protocol for a range of Saudi wheat genotypes. Seven wheat genotypes were evaluated in anther culture on five different medium protocols for their ability to initiate callus and green plants. The estimates of significance for the effects of genotypes, and medium protocols used, and their interactions on callus induction, callus weight and shoot formation derived from anther explants indicated that the in vitro traits were significantly influenced by the genotypes, medium protocols, and their interactions. The percentage of explants that developed calli ranged from 0.41% (Lang) to 15.39% (Irena) averaged across the five medium protocols with an average 4.45%. The genotype Irena produced the highest average means of shoot formation (69.65%) across medium protocols. The genotype Yecora Rojo (13.73%) was significantly inferior to all other tested genotypes for shoot formation.

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Abstract

Evaluation studies were carried out to simulate realistic field exposures of sulfoxaflor and flonicamid against Aphis gossypii at foraging time of Apis mellifera. Semi-field trials of field rates of sulfoxaflor and flonicamid against A. gossypii laboratory strain at 48 h of exposure had equipollent overall mean of mortality of 62.50 and 63.50%, respectively in season of 2020, likewise 60.50 and 62.50%, respectively in season of 2021. Lethal time values (LT1) had ranges of 51.33–32.46 days for sulfoxaflor and 49.00–39.55 days for flonicamid. Laboratory trials on foraging honeybees (∼21 days old) at 5 h of exposure showed an excellence for sulfoxaflor (5.00%) in overall mean of mortality compared to flonicamid (2.75%) in season of 2020. Likewise, sulfoxaflor (4.75%) surpassed flonicamid (2.75%) in season of 2021. The highest LT1s on honeybees for sulfoxaflor and flonicamid reached 27.45 and 10.94 days, respectively. International Organization for Biological Control classified both insecticides to be harmless on honeybees. Survival foraging bees exposed to LD50s of the tested insecticides had malformed digestive tracts gradually vanished along week of exposure. Suggestions for foliar spray stoppages prior to flowering period were mentioned for both insecticides.

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Bacillus thuringiensis (B.t) is well known for its biocontrol potential against a variety of insects. Nematicidal potential of ten B.t isolates was tested against root-knot nematodes (Meloidogyne javanica (Treub) Chitwood) in vitro, under greenhouse as well as in field conditions. Eggs and second stage juveniles (J2) were exposed to 5 and 25% concentrations of bacterial cell-free aqueous extracts up to 96 h. B.t isolates showed lesser degrees of nematicidal activity at 5% concentration. However, some B.t isolates (B.t-14, B.t-16 and B.t-64) greatly reduced egg hatching and increased J2. All B.t isolates revealed suppressed egg hatching and increased mortality of J2 at 25% concentration. Soil applications with most of the B.t isolates under greenhouse and field conditions significantly improved height and fresh weights of root-knot nematode parasitized okra (Abelmoschus esculentus (L.) Moench). Some isolates, including B.t-64 reduced the number of galls and egg masses. B.t-64 reduced gall formation up to 70% under greenhouse conditions. However, 29% of decrease was observed in field conditions. Similarly, B.t-64 treated plants showed a 56% decreased in eggs/egg mass in a field experiment. Population of root-knot nematodes in the rhizosphere was decreased up to 61% in the field experiment as compared to control.

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Cereal Research Communications
Authors: M. Oyekunle, A. Menkir, H. Mani, G. Olaoye, I.S. Usman, S.G. Ado, U.S. Abdullahi, H.O. Ahmed, L.B. Hassan, R.O. Abdulmalik, and H. Abubakar

Genotype × environment interactions complicate selection of superior genotypes for narrow and wide adaptation. Eighteen tropically-adapted maize cultivars were evaluated at six locations in Nigeria for 2 yrs to (i) identify superior and stable cultivars across environments and (ii) assess relationships among test environments. Environment and genotype × environment interactions (GEI) were significant (P < 0·05) for grain yield. Environments accounted for 63.5% of the total variation in the sum of squares for grain yield, whereas the genotype accounted for 3.5% and GEI for 32.8%. Grain yield of the cultivars ranged from 2292 kg ha–1 for DTSTR-W SYN2 to 2892 kg ha−1 for TZL COMP4 C3 DT C2 with an average of 2555 kg ha−1. Cultivar DT SYN2-Y had the least additive main effect and multiplicative interaction (AMMI) stability value of 7.4 and hence the most stable but low-yielding across environments. AMMI biplot explained 90.5% and classified cultivars and environments into four groups each. IWD C3 SYN F3 was identified as the high-yielding and stable cultivar across environments. ZA15, ZA14, BK14, BK15 and IL15 had environment mean above the grand mean, while BG14, BG15, LE14, LE15, IL14, LA14 and LA15 had mean below the grand mean. ZA, BK, BG, LE and LA were found to be consistent in ranking the maize cultivars. However, Zaria, Birnin Kudu, and Ilorin were identified as the best test locations and could be used for selecting the superior maize cultivars. The identified high-yielding and stable cultivar could be further tested and promoted for adoption to contribute to food insecurity in Nigeria.

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