A field experiment was conducted to investigate the effects of paclobutrazol on ear characteristics and grain yield by regulating root growth and root-bleeding sap of maize crop. Seed-soaking at rate of 0 (CK1), 200 (S1), 300 (S2), and 400 (S3) mg L−1, and seed-dressing at rate of 0 (CK2), 1.5 (D1), 2.5 (D2), and 3.5 (D3) g kg−1 were used. Our results showed that paclobutrazol improved the ear characteristics and grain yield, and were consistently higher than control during 2015–2016. The average grain yield of S1, S2 and S3 were 18.9%, 61.3%, and 45.9% higher, while for D1, D2 and D3 were 20.2%, 33.3%, and 45.2%, compared to CK, respectively. Moreover, paclobutrazol-treated maize had improved root-length density (RLD), root-surface area density (RSD) and root-weight density (RWD) at most of the soil profiles (0–70 cm for seed-soaking, 0–60 cm for seed-dressing) and was attributed to enhancing the grain yield. In addition, root-activity, root-bleeding sap, root dry weight, diameter and root/shoot ratio increased by paclobutrazol, with highest values achieved in S2 and D3 treatments, across the whole growth stages in 2015–2016. Our results suggested that paclobutrazol could efficiently be used to enhance root-physiological and morphological characteristics, resulting in higher grain yield.

Drought stress is one of the most immense and permanent constraints in agriculture, which leads to a massive loss of crop productivity. However, little is known about the mitigation role of exogenously applied abscisic acid (ABA) and jasmonic acid (JA) in pearl millet (Pennisetum glaucum L.) under PEG-induced drought stress. Therefore, the current study investigated the putative role of exogenous ABA and JA in improving drought stress tolerance in pearl millet. Thirteen-day-old seedlings were exposed to six different treatments as follow; control (ck), PEG-600 (20%), JA (100 μM), ABA (100 μM), PEG+JA, and PEG+ABA, and data were collected at 7 and 14 days after treatment (DAT). Results showed that PEG decreased plant growth while the oxidative damage increased due to over production of H 2 O 2 and MDA content as a result of decreased activities of the antioxidative enzymes including APX, CAT, and SOD in the leaves. However, exogenous ABA and JA positively enhanced the growth profile of seedlings by improving chlorophyll and relative water content under PEG treatment. A significant improvement was observed in the plant defense system resulting from increased activities of antioxidative enzymes due to exogenous ABA and JA under PEG. Overall, the performance of JA was found better than ABA under PEGinduced drought stress, and future investigations are needed to explore the potential effects of these phytohormones on the long-term crop management and productivity under drought stress.

Strip width management is a critical factor for producing higher crop yields in relay intercropping systems. A 2-year field experiment was carried out during 2012 and 2013 to evaluate the effects of different strip width treatments on dry-matter production, major-nutrient (nitrogen, phosphorus, and potassium) uptake, and competition parameters of soybean and maize in relay intercropping system. The strip width (SW) treatments were 0.40, 0.40, and 0.40 m (SW1); 0.40, 0.40, and 0.50 m (SW2); 0.40, 0.40, and 0.60 m (SW3); and 0.40, 0.40, and 0.70 m (SW4) for soybean row spacing, maize row spacing, and spacing between soybean and maize rows, respectively. As compared to sole maize (SM) and sole soybean (SS), relay-intercropped maize and soybean accumulated lower quantities of nitrogen, phosphorus, and potassium in all treatments. However, maize in SW1 accumulated higher nitrogen, phosphorus, and potassium than SW4 (9%, 9%, and 8% for nitrogen, phosphorus, and potassium, respectively). Soybean in SW3 accumulated 25% higher nitrogen, 33% higher phosphorus, and 24% higher potassium than in SW1. The improved nutrient accumulation in SW3 significantly increased the soybean dry matter by 19%, but slightly decreased the maize dry matter by 6% compared to SW1. Similarly, SW3 increased the competition ratio value of soybean (by 151%), but it reduced the competition ratio value of maize (by 171%) compared to SW1. On average, in SW3, relay-cropped soybean produced 84% of SS seed yield and maize produced 98% of SM seed yield and achieved the land equivalent ratio of 1.8, demonstrating the highest level in the world. Overall, these results suggested that by selecting the appropriate strip width (SW3; 0.40 m for soybean row spacing, 0.40 m maize row spacing, and 0.60 m spacing between soybean and maize rows), we can increase the nutrient 2 of 14 | RAZA et Al.

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To the best of our knowledge, for the first time our research examines a role of secondary cell wall components in lodging resistance and their interaction with yield under intercropping.

Plants react to the environment and to management interventions by undergoing architectural and structural modifications. A field trial was conducted in China in 2016 to study the effects of the plant population on morphological development of the maize canopy. The main objectives of the current study were (i) to characterize the effects of increased plant density on canopy morphology and stalk lodging and (ii) to explore the relationships between organ morphology and stalk lodging. The field experiment was composed of five plant densities (4.5, 6, 7.5, 9, and 15 plants m−2) of three cultivars: Zhengdan 958 (lodging-resistant cultivar), Longping 206 and Jinqiu 119 (lodging-susceptible cultivars). In response to plant densities of all the three cultivars, the lamina and sheath lengths increased in lower phytomers but decreased in upper phytomers. The lamina width and internode diameter decreased for all phytomers in response to plant densities for all the cultivars. The correlation between organ morphology, plant density and stalk lodging was linear. Data obtained from characterization used in this study (that is, canopy morphology, correlation of organ morphology with stalk lodging traits in response to various plant densities for different cultivars, etc.) will be useful in future modeling studies to predict the morphology characteristics of the canopy affected by interplant competition and stalk lodging.

Influences of planting density and nitrogen rate have been investigated frequently in targeted wheat (Triticum aestivum L.) research. Few studies have investigated interactions between these inputs. The objective was to determine the combine effect of N and seeding rates on culm morph‐physiological traits for lodging tolerance and grain yield. The experiment used a split‐split randomized block design using two wheat varieties ‘AnNong0711’ and ‘YanNong19’, split by four seeding (180, 240, 300, and 375 × 104 ha−1) and four N rates (0, 180, 240, and 300 kg ha−1). Lodging traits of plant height, culm height center of gravity, and internode length, increased (p < .05) however, stem diameter, wall thickness, and stem breaking strength decreased with increasing N and seeding rate. Stem breaking strength was negatively correlated with culm height center of gravity (r = −.869, p = .01), internode length (r = −.872, p < .01), and lignin (r = −.746, p < .01) but positively correlated with internode diameter (r = .715, p < .05) and wall thickness (r = .696, p < .05). Culm lodging index and cellulose showed positive correlation (r = .807 and .913 respectively) with lignin. Compared to YanNong19, AnNong0711 showed higher grain yield and culm lodging index of 9 and 20.49%, respectively. For improved grain yield, 180 plants m−2 was optimal in surface combinations with 210 kg N ha−1 for AnNong0711 and 200 kg N ha−1 for YanNong19. These combinations of seeding and N rates could successfully mitigate lodging and improve grain yield.

Bioavailability of cadmium (Cd) metal in the soils due to scarcity of good quality water and industrial waste could be the major limiting factors negatively influencing the growth and yield of crops needs prompt solution to fulfil the requirement of food for increasing world population. In the recent time, variable range of plant growth promoting rhizobacteria (PGPR) are being used on large scale in agriculture to reduce the risk of abiotic stresses on plants and increase crop productivity. Among them, the Bacillus siamensis has a huge potential to enhance the plant tolerance against abiotic stress but limited evidences are reported about the putative role of B.s in crop plants under heavy metal stress. The current study was aimed to investigate the potential of a new metal tolerant strain of B.s on two wheat (Triticum aestivum L.) varieties (NARC-2009 and NARC-2011) grown in Cd contaminated soil at different treatments i.e Cd (0, 20, 30 and 50 ppm) and Cd (0, 20, 30 and 50 ppm) + B.s. Our results depicted that Cd stress decreased the wheat growth related attributes, biomass, and photosynthetic parameters (Chlorophyll a, b and a + b) which increased in both wheat varieties upon inoculation with B.s. Moreover, Cd stress caused significant membrane damage and negatively affected the water content, water potential, and osmotic potential of leaf. However, PGPR considerably increased the soluble sugars to reduce the Cd toxicity. Overall, the plants inoculated with B.s enhanced their tolerance index of root and shoot and found better in NARC-2009 than NARC-2011. Therefore, microorganisms efficiently increase the plant growth by reducing the metal toxicity.