Impact of calcium chloride concentrations and storage duration on quality attributes of peach (<Emphasis Type="Italic">Prunus persica</Emphasis>)

To investigate the impact of CaCl₂ concentrations and storage duration on quality of peach (Prunus persica), a research was conducted at postharvest Laboratory, Department of Horticulture, The University of Agriculture, Peshawar, Pakistan during 2012–2013. The experiment was laid out in Completely Randomized Design (CRD) with factorial arrangement repeated three times. The peach fruits (cv. Texas A 69) were harvested at physiological maturity stage from peach orchard, Horticulture Farm. The fruits were dipped in 0, 2 and 4% CaCl₂ solution for 10 min and transferred to cold storage having ±8–10°C with relative humidity of 80–85%. The application of CaCl₂ solution and storage duration significantly influenced the fruit quality of peach fruit. However, the application of CaCl₂ solution significantly reduced weight loss (4.98%), disease incidence (2.08%), total sugars (5.31%), TSS-Acid ratio (16.27), TSS(7.38⁰Brix) and increased the fruit firmness (2.21 kg cm^–2) titratable acidity (0.47%) and Ascorbic acid (5.35 mg/100 g) of peach fruits. The storage duration of peach fruit also significantly affected the fruit quality attributes during storage. The peach fruit stored for 30 days showed less fruit firmness (0.74 kg cm^–2) and titratable acidity (0.31%), Ascorbic acid (4.45 mg/100 g) and increased weight loss (19.74%), disease incidence (16.11%), total sugars (6.07%), TSSAcid ratio (27.62) and TSS(8.54⁰Brix) of peach fruit. Based on the findings of this study, it is concluded that the peach fruit should be treated with 4% CaCl₂ solution to retain the quality attributes for 30 days storage.     

Effect of short-term supply of farmyard manure on maize growth and soil parameters in pot culture

Farmyard manure (FYM) improves various soil parameters and to a large extent, the availability of water and nutrient to crops when it is applied to the soil. This study aims to further investigate the short-term effects of different levels of FYM on maize plants and soil parameters. Maize plants grown in pot culture were treated with no FYM (control), recommended NPK (inorganic fertilizers), and FYM at 2, 4, 6, 8, and 10 t ha^?1 along with recommended NPK, and the cultures were analyzed 8 weeks after germination. Soil bulk density and soil pH decreased with the increasing levels of FYM, whereas soil porosity, soil organic matter (SOM), soil water content, plant height, root and shoot yield, and NPK uptake of maize were increased compared with the control or recommended NPK, respectively. The present results indicate that short-term application of higher FYM levels improves soil properties. Furthermore, the application of FYM at only higher rates significantly increases the nutrient uptake of maize plants due to improved soil properties. The supply of different amounts of nutrients increases biomass and nutrient uptake in plants.     

On Red Rot of Sugarcane

Abstract

Red rot is a very serious disease of sugarcane. It was first described by Went in 1893 (56). Since then it has been found to cause epiphytotics in different countries. The surest symptom of the disease is the reddening of the internal internodal tissues with crossbars of white patches in the reddened area. This red colour is caused by a dye which is secreted by the host and is antagonistic to the red rot fungus. Infection takes place through mother setts, holes in the nodal regions, the cut ends of the seed canes and other injuries. The disease causes damage to the sugarcane drop mainly by reducing the crop stands and by reducing the sucrose content of the cane juice. Methods of chemical control are mentioned, although the importance of good husbandry is stressed. Use of resistant varieties of sugarcane is recommended.     

Barrier and Mechanical Properties of Starch‐Clay Nanocomposite Films

The poor barrier and mechanical properties of biopolymer‐based food packaging can potentially be enhanced by the use of layered silicates (nanoclay) to produce nanocomposites. In this study, starch‐clay nanocomposites were synthesized by a melt extrusion method. Natural (MMT) and organically modified (I30E) montmorillonite clays were chosen for the nanocomposite preparation. The structures of the hybrids were characterized by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Films were made through casting using granulate produced by a twin‐screw extruder. Starch/MMT composite films showed higher tensile strength and better water vapor barrier properties than films from starch/I30E composites, as well as pristine starch, due to formation of intercalated nanostructure. To find the best combinations of raw materials, the effects of clay content (0–21 wt% MMT), starch sources (corn, wheat, and potato), and amylose content (≈0, 28, 55, 70, 100%) on barrier and mechanical properties of the nanocomposite films were investigated. With increase in clay content, significantly higher (15–92%) tensile strength (TS), and lower (22–67%) water vapor permeability (WVP) were obtained. The barrier and mechanical properties of nanocomposite films did not vary significantly with different starch sources. Nanocomposite films from regular corn starch had better barrier and mechanical properties than either high amylopectin or high‐amylose‐based nanocomposite films. WVP, TS, and elongation at break (%E) of the films did not change significantly as amylose content increased beyond 50%.     

Influence of Nitric Oxide Application on Some Biochemical Aspects,Endogenous Hormones,Minerals and Phenolic Compounds of Vicia faba Plant Grown under Arsenic Stress

Arsenic is a non-essential and toxic heavy metal, which can cause physiological disorder in plants. The present study was undertaken to examine the possible roles of sodium nitroprusside (SNP, a donor of NO) in protection against oxidative damage due to arsenic (As) toxicity in faba bean (Vicia faba L.) plants. In this study, we measured physiochemical parameters (photosynthetic pigments, lipid peroxidation, endogenous hormones, minerals and phenolic contents) in faba bean plants exposed to AS (100, 200 and 400 µM) alone or combined with NO (100 µM). The results showed that application of all concentrations of arsenic (100, 200 and 400 µM) induced decrease on growth parameters, seed yield, photosynthetic pigments, phytohormones, minerals contents (N^3?, P^3?, K⁺, Ca²⁺?and Mg²⁺) as compared to control plants but increased lipid peroxidation, Na?⁺ and total phenolic compounds fraction. Foliar application of 100 µM NO reversed the inhibition induced by As treatment. In addition, arsenic was undetected in harvested seeds at all applied concentrations of arsenic. Therefore, it could be concluded that NO might account for the alleviating effect of As stress on Vicia faba plants.     

Drought-induced anatomical changes in radish (Raphanus sativus L.) leaves supplied with trehalose through different modes

Leaf anatomical changes were appraised in exogenously applied trehalose of radish (Raphanus sativus L.) plants grown under nonstress (well-watered) and water stress (60% field capacity) conditions. Two cultivars of radish namely, Manu and 40-Day, were grown in a pot experiment at the Botanical Garden, GCUF, Pakistan. Plants were subjected to 60% field capacity conditions after three weeks of germination. Trehalose (25 mM) was applied to the radish plants through two different modes (foliar and presowing). After 2 weeks of foliar-applied trehalose, the leaves were excised from the plants for studying different anatomical features. Water stress caused a significant reduction in the leaf vascular bundle area, leaf midrib thickness (only in cv. Manu), leaf parenchyma cell area, and the number of vascular bundles in both radish cultivars, while water stress increased leaf epidermis thickness of both radish cultivars. Exogenously applied trehalose through both (presoaking and foliar spray) modes was effective in increasing leaf epidermis thickness, vascular bundle area, midrib thickness, and number of vascular bundles in both radish cultivars under water stress and nonstress conditions. Foliar-applied trehalose was more effective in increasing midrib thickness in both radish cultivars under both water regimes. Of both cultivars, the performance of cv. Manu was better in leaf epidermis thickness, leaf midrib thickness, vascular bundle area, leaf parenchyma cell area, and the number of vascular bundles. Overall, exogenous application of trehalose through both modes was effective in triggering leaf anatomical changes under different water regimes.     

Comparison of various potting media for their influence on nutrients supply,germination, and growth of muskmelon (cucumis melo L.) seedlings

Peat moss is used as potting mix for growing muskmelon (Cucumis melo L.) seedlings. However, it is not economical for most of the farmers in developing countries. The objectives of the present study were to compare various sources of composts as substitutes for peat moss, evaluate their physicochemical properties, and their effects on germination and growth of muskmelon (Cucumis melo L.) seedlings under greenhouse conditions. The treatments included pure peat moss (control), and composts prepared from guar (Cyammopsis tetragonoloba L.), jantar (Sesbania aculeate L.), and wheat (Triticum aestivum L) straw, at three air-filled porosity (AFP) levels (10, 15, and 20%) and rice (Oryza sativa) hulls at 10% AFP level. The second factor was the addition and devoid of nitrogen (N), phosphorus (P), and potassium (K) fertilizers. The addition of fertilizers in all potting media at 10% AFP level showed a small increase in total nitrogen, extractable phosphorus, and potassium. In the guar and jantar compost at 10% AFP, the values of total N (92.43 and 85.32%), extractable P (68.13 and 76.65%), and K (63.33 and 49%) were higher than in peat moss. It is concluded that composts of guar, jantar, wheat straw, and rice hulls at 10% AFP level can be used as a substitute of peat moss for growing muskmelon seedlings, but the addition of N, P, and K fertilizers is required in wheat straw and rice hulls compost for better nutrition of muskmelon seedlings.     

Molecular and phenotypic diversity of ICARDA spring barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.) collection

Plant breeders are interested in using diverse genotypes in hybridization that can segregate for traits of importance with possibility of selection and genetic gain. Information on molecular and agro-morphological diversity helps the breeders reduce the effort for parental selection and helps the advancement of generations. A phenotypic and molecular diversity study, using 24 traits (agronomic and disease) and 6519 SNPs in a diverse collection of 336 spring barley genotypes, was carried out at Marchouch and Jemma Shiam research stations in Morocco. Based on structure and multivariate analyses, strong differentiation between the two- and six-row types were observed. The linkage disequilibrium (LD) decay of the current collection (for the combined population) was up to 3.58 cM (r ² = 0.15) while LD decay were estimated 3.91 and 2.36 cM for two- and six-row barley, respectively. PCA of agro-morphological traits revealed grain per spike, net form of net blotch (NFNB), spot form of net blotch (SFNB), and 1000 kernel weight were the most discriminatory traits in the current collection. Association mapping in the two independent populations will be ideal for identification of markers, and QTL related to traits. The generated information on relatedness between individuals will help identify diverse genotypes for breeding programs.     

基质类型及烯效唑对不同秧龄晚稻机插质量和产量的影响

为明确基质类型及烯效唑对不同秧龄晚稻秧苗生理特征及本田期生长发育特性的影响,确定适宜晚稻机插育秧的基质类型、烯效唑浸种措施及秧龄,该研究以嘉58为供试晚稻品种,以2种代表性育秧介质(营养土和轻型无土育秧基质)为研究对象,采用2种(清水浸种和25 mg/L烯效唑浸种)外源生长调控措施,阐明了不同育秧介质和烯效唑浸种对不同秧龄晚稻秧苗生理特征、机插质量的影响及调控技术。结果表明,随晚稻秧龄延长,秧苗地上部分干物质量显著增加,叶片SPAD值和根系活力先增加后降低;水稻全生育期延长,大田生育期缩短。采用烯效唑浸种可提高秧苗素质,浸种处理秧苗茎基宽约增加0.1~0.2 mm,株高显著降低,叶片SPAD值和根系活力显著提高。短秧龄条件下烯效唑浸种对秧块质量和机插质量影响较小,长秧龄条件下烯效唑浸种可有效提高成苗率和大田基本苗数,降低漏插率和伤秧率。采用营养土育秧时最适机插秧龄为18 d,轻型无土基质育秧适宜机插秧龄为18~24 d。秧龄大于24 d时,烯效唑浸种可提高营养土育秧晚稻有效穗数和每穗粒数,增加晚稻产量,且秧龄越长,烯效唑浸种的增产效果越显著。烯效唑浸种对轻型无土基质育秧的产量影响较小。采用轻型无土育秧基质培育机插晚稻秧苗,产量高于常规营养土处理,适宜晚稻机插育秧。研究结果可为提升晚稻种植机械化水平提供重要参考。