Ahmad Sher

Late harvest associated with P and S fertilization enhances yield and quality of forage sorghum (Sorghum bicolor (L.) Moench), grown as a rainfed crop in Pakistan

-1 ), in combination with three levels of sulphur (0, 20 and 40 kg SO 4 ha -1 ), in combination with three harvest times (35, 45 and 55 days after emergence; DAE), were tested in a factorial randomized block design. At each harvest, morphological, functional, yield and quality traits were assessed on plant samples. Extending the growing season from DAE 35 to 55 enhanced almost all the traits and greatly benefited dry biomass yield (ca. +100%). The longer growth also determined a higher efficiency in the accumulation of dry biomass per unit time and land surface (crop growth rate ca. +30%), as well as per unit time and leaf surface (net assimilation rate ca. +100%). Quality traits also improved when plants were harvested at a more advanced maturity: leaf hydrocyanic acid content, a toxic component to livestock, decreased by ca. 30%; stalk soluble-solid content, an indicator of forage juiciness and palatability, increased by ca. 50%. On concluding, the combined effects of harvest delay, P and S fertilization on sorghum are deemed able to significantly increase forage production in warm, relatively dry areas of the world.

Separate and combined effects of silicon and selenium on salt tolerance of wheat plants

Soil salinity is the leading global abiotic stress which limits agricultural production with an annual increment of 10%. Therefore; a pot experiment was conducted with the aim to alleviate the salinity effects on wheat seedlings through exogenous application of silicon (Si) and selenium (Se). Treatments included in the study were viz. (Ck) control (no NaCl nor Si and Se added), only salinity (50 mM NaCl), salinity + Si (50 mM NaCl with 40 mM Si), salinity + Se (50 mM NaCl with 40 mM Se) and salinity + Si + Se (50 mM NaCl + 40 mM Si + 40 mM Si). The salt stress impaired the growth (root and shoot dry weight, root: shoot ratio, seedlings biomass), water relations, photosynthetic attributes, transpiration rate and chlorophyll contents of wheat seedlings. Nonetheless, the foliar application of Si and Se alone and in combination improved the growth, water relations, photosynthetic attributes, transpiration rate and chlorophyll contents of wheat seedlings under stressed conditions. Moreover, an increase in antioxidant enzyme activity and accumulation of osmo-protectants (proline, soluble protein and soluble sugar) was noted under stressed conditions, which was more pronounced in wheat seedling which experienced combined application of Si and Se. To conclude that, foliar application of Si alone mitigated the adverse effect of salinity, while the combined application of Si and Se was proved to be even more effective in alleviating the toxic effects of salinity stress on wheat seedlings.

Water stress effects on biochemical traits and antioxidant activities of wheat (Triticum aestivum L.) under In vitro conditions

ABSTRACT Water stress is one of the major environmental stresses that affect agricultural production worldwide, especially in arid and semi-arid regions. This research investigated the effect of water deficit, induced by PEG-6000 on wheat genotypes (GA-2002, Chakwal-97, Uqab-2000, Chakwal-50 and Wafaq-2001) grown in modified MS medium solution. Osmotic stress caused a more pronounced inhibition in leaf relative water content and leaf membrane stability more sensitive (index in Wafaq-2001 and Uqab-2000) genotypes compared with the tolerant (Chakwal-50, GA-2002 and Chakwal-97) genotypes. Upon dehydration, an incline in proline, total soluble sugar, total soluble protein, superoxide dismutase, peroxidase, catalase and malondialdehyde activity content were evident in all genotypes, especially at osmotic stress of −8 bars. The observed data showed that status of biochemical attributes and antioxidant enzymes could provide a meaningful tool for depicting drought tolerance of wheat genotypes. The present study shows that genotypic differences in drought tolerance could be likely attributed to the ability of wheat plants to induce antioxidant defense under drought conditions. In order to develop genotypes with stable, higher yields in dry farming conditions, it is necessary to characterise genetic resources based on drought adaptation, determine suitable genotypes, and then use them in breeding programmes.

Sunflower (Helianthus annuus) Hybrids Evaluation for Oil Quality and Yield Attributes under Spring Planting Conditions of Haripur, Pakistan

Field experiment was conducted at the University of Haripur, Pakistan, to explore the role of photothermal units on oil contents, fatty acids profile, yield and yield traits of four sunflower hybrids viz SMH-0917, NK-S-278, SMH-0907 and Hysun33. These sunflower hybrids were selected because the farmers of that area are mostly relying on these hybrids for sunflower production. Sunflower hybrids were sown in spring and arranged under Randomized Complete Block Design with 3 replications under field conditions. Significant variation (p ≤ 0.05%) was found among the sunflower hybrids for photothermal unit requirements for flower completion and physiological maturity. Highest photothermal unit accumulation was found in Hysun33 followed by SMH-0917 and SMH-0907. Highest seed oil content and oil composition (linoleic and oleic acid were most abundant, whereas palmitic acid was least) was recorded in Hysun-33, SMH-0917 and SMH-0907. Overall Hysun-33, SMH-0917 and SMH-0907 performed better for plant height, head diameter, number of achenes per head and achene yield under field conditions. It was also observed that temperature and moisture availability positively influenced the oil quality of sunflower hybrids under spring planting conditions. The significant amount of variation within the sunflower population for photothermal unit accumulation, oil content, oil quality, and yield traits under these uniform field conditions reveals potential genetic variation that could be useful in breeding early maturing and high yielding local sunflower hybrids.

INFLUENCE OF DIFFERENT METHODS AND TIME OF PHOSPHORUS FERTILIZER APPLICATION IN WHEAT UNDER ARID CONDITION

A field experiment was conducted to study the effect of different time and methods of application of phosphatic fertilizer to wheat crop under Arid condition. Experiment was comprised of five treatments viz: T1= Control, T2= P2O5 broadcast at the time of seedbed preparation in the form of (TSP), T3 = P2O5 side drilling after sowing, 5 cm apart rows and 5 cm deep with Rabi hand drill, T4= P2O5 broadcast after sowing at the time of first irrigation and T5= P2O5 mixed with seed of wheat. Results showed that although all the treatments tested were differing significantly from the control in all aspects studied but, application of phospahtic fertilizer (P2O5) side drilling after sowing, 5 cm apart rows and 5 cm deep with Rabi hand drill, produced maximum germination percentage (82.15), plant height (108.50 cm), number of fertile tillers m (356), number of grains spike (41.50), 1000 grains weight (42.40 g) and grain yield (5.08 t ha) as compared to other treatments. Maximum P contents in the straw, grain, total P uptake and protein contents in grain were recorded in T5 was statistically at par with the T4 and T3. On the basis of these results, it can be concluded that application of phosphatic fertilizer at 5 cm apart side dressing of the rows at a depth of 5 cm not only increase the plant vigor but also produced better yield under arid condition.

Combined Application of Natural Plant Water Extracts and Biochar Improves the Productivity of Bread Wheat

Bread wheat (Triticum aestivum L.) is staple of Pakistani people. However, its yield at farmer field is low as compared with its genetic potential. Integration of various crop and soil management strategies might be an option to enhance wheat productivity at farmer field. This 2-year experiment was conducted to check the influence of combine application of natural plant water extracts and biochar on the productvity of wheat during the winter season of 2015-16. The experiment consisted of seven treatment viz. (1) control (2) application of biochar (0.18 kg pot) alone, (3) application of sorghum water extract (SWE) alone, (4) application of moringa water extract (MWE) alone, (5) application of biochar + SWE, (6) application of biochar + MWE, (7) application of biochar + SWE+MWE. The results revealed that application of both crop water extracts in combination with biochar improved the growth and grain yield of wheat. Use of MWE in combination with biochar enhanced the grain weight, grain number and grain yield of wheat by 44, 14, and 24%, respectively than the control treatment. In crux, use of MWE in combination with biochar might be a viable option to improve the productvity of bread wheat.

Photo-induced changes in quality attributes of potato tubers during storage

The retail display of potato tubers is carried out in supermarkets under additional light sources to impart aesthetic value and consumer’s attention, however, is associated with potato greening and associated disorders. The objective of this study was to identify a most appropriate light source for potato variety ’Lady Rosetta‘ along with photo-induced changes in different quality parameters. Potato tubers were placed for 27 days at ambient storage (25 ± 2 °C) under different light sources i.e. blue, fluorescent, green, mercury and red along with dark storage, which also served as normal control. In general, quality parameters, such as sugars, chlorophyll, total glycoalkaloids, increase while attributes, such as starch and ascorbic acid decrease during the storage period. The initial increase followed by final decline has been observed in parameters, such as total phenolic contents and radical scavenging activity. The results showed maximum retention of different quality attributes in dark potato storage. Amongst different light sources mercury and green light retained appreciable retention of different quality parameters with non-significant difference estimated between them in most of the studied parameters. Storage of potato under fluorescent, red and blue light proved to be precarious due to skin discoloration. Overall results revealed tuber sensitivity to different colored light along with their potential storage stability in the retail markets.

Influence of Priming on Emergence, Weed Infestation, Growth and Yield of Wheat Sown under Different Tillage Practices

Tillage practices are generally used to prepare seedbed and to control weeds but frequent use of tillage practices accelerate the degradation of soil resources and creates plough pan. However, zero tillage (ZT) has potential to overcome the tillage-induced restrictions and ensure timely wheat planting as well. Moreover, ZT resulted in poor and erratic emergence while seed priming could be used to improve emergence under ZT. Hence this experiment was conducted to evaluate the role of seed priming to improve wheat performance under varying tillage practices. Wheat seeds were soaked in water for 8 h (on-farm priming), CaCl2 solution (ψs –1.25 MPa; osmopriming) for 18 h and aerated water (hydro-priming) for 18 h. Unprimed dry seeds were used as control. Primed and unprimed seeds were sown under ZT, conventional tillage (CT), deep tillage (DT) and on beds. Zero tilled wheat observed delayed and poor emergence; however, seed priming, osmopriming in particular, resulted earlier and more synchronized emergence under all tillage practices. Zero tilled wheat had more weed prevalence while DT and bed sowing (BS) recorded lesser weeds infestation. Osmopriming resulted in quick and more uniform stand leading to significantly better allometric traits and crop yield. Bed sown wheat using osmoprimed seeds harvested the maximum yield due to increase in all yield related traits while zero tilled wheat using unprimed seeds behaved poorly in this regard. In conclusion, bed sown wheat using osmoprimed seeds observed early and uniform emergence, lesser weeds infestation, higher wheat yield and net returns.

Exogenous silicon application alleviates salt stress in okra

Salt stress is known to adversely affect a variety of processes in plants, inhibiting growth and decreasing crop yield. Silicon (Si) protects plants against a variety of environmental stresses. In the present study, seedlings of two genotypes of okra (Abelmoschus esculentus L. Moench; salt-tolerant OH-713 and salt-sensitive Okra-7080) were subjected to four treatments; control (no NaCl or Si added), only Si (150 mg·L-1 Si), only salinity (6.0 dS·m-1 ), or salinity + Si, to observe their response at the morphological, physiological, and enzymatic level. The application of Si in stressed okra cultivars led to significant improvements, including increasing the leaf area and leaf area index, decreasing the leaf water potential and osmotic potential, and enhancing the turgor potential and relative water contents. It also increased the activity of the enzymatic antioxidants ascorbate peroxidase and guaiacol peroxidase, as well as increasing nitrate reductase levels and activity. The suppressed concentrations of calcium (Ca) and magnesium (Mg) ions under salt stress were alleviated by the application of Si. The results of the current investigation suggested that Si confers salt tolerance to okra, potentially by enhancing their water status, improving antioxidant activity, and enhancing nitrogen metabolism.

Physiological response of late sown wheat to exogenous application of silicon

Late planting of wheat in rice-wheat cropping system is perhaps one of the major factors responsible for low crop yield. The main cause of reduction in yield is due to supra-optimal conditions during the reproductive growth. High temperature during reproductive phase induces changes in water relations, decreases photosynthetic rate, and transpiration rate, stomatal conductance and antioxidative defence system. Silicon (Si), being a beneficial nutrient not only provides significant benefits to plants growth and development but may also mitigate the adversities of high temperature. A field study was conducted at Agronomic Research Area of University of Agriculture; Faisalabad, Pakistan to assess the performance of late sown wheat with the soil applied Si. Experiment was comprised of three sowing dates; 10th Nov (normal), 10th Dec (late), 10th Jan (very late) with two wheat varieties (Sehar-2006 and Faisalabad-2008), and an optimized dose of Si (100 mg per kg soil), applied at different growth stages (control, crown root, booting and heading). Results indicated that 100 mg Si per kg soil at heading stage offset the negative impact of high temperature and induced heat tolerance in late sown wheat. Silicon application improved 34% relative water contents (RWC), 30% water potential, 26% osmotic potential, 23% turgor potential and 21% photosynthetic rate, and 32% transpiration rate and 20% stomatal conductance in wheat flag leaf than control treatment. Further it was observed that Si application preventing the oxidative membrane damage due to enhanced activity of antioxidant enzymes, i.e. 35% superoxide dismutase (SOD) and 38% catalase (CAT). In conclusion results of this field study demonstrated that soil applied Si (100 mg per kg soil) at heading stage enhanced all physiological attributes of wheat flag leaf. Which in turn ameliorated the adverse effects of high temperature in late sown wheat. Study depicted that Si can be used as a potential nutrient in order to mitigate the losses induced by high temperature stress.