Hafeez ur Rehman

Seed Priming Influence on Early Crop Growth, Phenological Development and Yield Performance of Linola (Linum usitatissimum L.)

Reduced early crop growth and limited branching are amongst yield limiting factors of linola. Field response of seed priming treatments viz. 50 mmol L−1 salicylic acid (SA), 2.2% CaCl2 and 3.3% moringa leaf extract (MLE) including untreated dry and hydropriming controls was evaluated on early crop growth and yield performance of linola. Osmopriming with CaCl2 reduced emergence time and produced the highest seedling fresh and dry weights including Chl. a contents. Osmopriming with CaCl2 reduced crop branching and flowering and maturity times and had the maximum plant height, number of branches, tillers, pods and seeds per pod followed by MLE. Increase in seed weight, biological and seed yields was 9.30, 34.16 and 39.49%, harvest index (4.12%) and oil contents (13.39%) for CaCl2 osmopriming. Positive relationship between emergence and seedling vigor traits, 100-seed weight, seed yield with maturity time, 100-seed weight and seed yield were found. The study concludes that seed osmopriming with CaCl2 or MLE can play significant role to improve early crop growth and seed yields of linola.

Seed priming improves early seedling vigor, growth and productivity of spring maize

Abstract Potential of seed priming treatments in improving the performance of early planted maize was evaluated against timely planting. Seeds of maize hybrid FH-810 were soaked in water (hydropriming), CaCl2 (2.2%, osmopriming), moringa leaf extracts (MLE 3.3%, osmopriming) and salicylic acid (SA, 50 mg L−1, hormonal priming) each for 18 h. Untreated and hydroprimed seeds were taken as control. Seeds primed with SA took less time in emergence and had high vigor in early planted maize. Amongst treatments, hormonal priming, reduced the electrical conductivity, increased the leaf relative and chlorophyll contents followed by osmopriming with CaCl2 at seedling stage. Likewise, plant height, grain rows and 1 000-grain weight, grain and biological yield and harvest index were also improved by seed priming; however hormonal priming and osmopriming with MLE were more effective in this regard. Improved yield performance by hormonal priming or osmopriming with MLE in early planting primarily owed to increased leaf area index, crop growth and net assimilation rates, and maintenance of green leaf area at maturity. In conclusion, osmopriming with MLE and hormonal priming with SA were the most economical treatments in improving productivity of early planted spring maize through stimulation of early seedling growth at low temperature.

Allelopathic activity and chemical constituents of walnut (Juglans regia) leaf litter in walnut–winter vegetable agroforestry system

Walnut agroforestry systems have many ecological and economic benefits when intercropped with cool-season species. However, decomposing leaf litter is one of the main sources of allelochemicals in such systems. In this study, lettuce (Lactuca sativa var. angustata) was grown in the soil incorporated with walnut leaf litter to assess its allelopathic activity. Lettuce growth and physiological processes were inhibited by walnut leaf litter, especially during early growth stage (1–2 euphylla period) or with large amount of litter addition. The plants treated by small amount of leaf litter recovered their growth afterwards, while the inhibition for 180 g leaf litter persisted until harvest. Twenty-eight compounds were identified in the leaf litter, and several of them were reported to be phytotoxic, which may be responsible for the stress induced by walnut leaf litter. Thus, for highest economic value of vegetables such as lettuce, excessive incorporation of leaf litter should be discouraged.

Moringa Leaf Extract Improves Wheat Growth and Productivity by Affecting Senescence and Source-sink Relationship

The effect of exogenously-applied Moringa (Moringa oleifera Lam.) leaf extract (MLE) on delaying the leaf senescence and modifying the source-sink relationship in wheat (Triticum aestivum L.) was studied. MLE (3.3%) was used as seed osmopriming (SP) and/or foliar spray (F), and water as hydropriming (HP). Among seedling attributes, improved shoot and root lengths, leaf and root scores were found for SP and/or F treatments. Increase or decrease in stem dry weight simultaneously with grain dry weight might contribute for soluble stem reserves towards grain weight as showed by delayed leaf senescence in SP or combined SP+F treatment. The SP and F treatments had also earlier spike emergence and anthesis stage. Plant height, tillers number, biological and grain yields per plant were also recorded highest for SP+F treatment followed by SP. Thus, MLE being rich in zeatin, a cytokinin maintained the green photosynthetic area and enhanced grain filling that might contributed towards improved grain yield when applied as SP or in combination with foliar.

Recent Advances in Seed Enhancements

Seed quality is vital to sustainable crop production and food security. Seed enhance‐ ments include physical, physiological and biological treatments to overcome germina‐ tion constraints by uniform stands, earlier crop development and better yields. Improved germination rates and seedling vigour are due to reduced emergence time by earlier start of metabolic activities of hydrolytic enzymes and resource mobiliza‐ tion. Nutrient homeostasis, ion uptake, hormonal regulation, activation of antioxidant defence system, reduced lipid peroxidation and accumulation of compatible solutes are some mechanisms conferring biotic and abiotic stress tolerance. Several transcription factors for aquaporins, imbibitions, osmotic adjustment, antioxidant defence and phenylpropanoid pathway have been identified. However, the knowledge of molecu‐ lar pathways elucidating mode of action of these effects, reduced longevity of primed or other physical and biological agents for seed treatments and market availability of high-quality seeds are some of the challenges for scientists and seed industry. In this scenario, there is need to minimize the factors associated with reduced vigour during seed production, improve seed storage and handling, develop high-tech seeds by seed industry at appropriate rates and integrate agronomic, physiological and molecular seed research for the effective regulation of high-quality seed delivery over next generations.

Potash use in aerobic production system for basmati rice may expand its adaptability as an alternative to flooded rice production system

Direct seeded aerobic rice system has been developed and adopted as an alternative for medium-grain rice in many parts of the world, whereas efforts for aerobic basmati rice types are still in infancy. Among two major constraints for aerobic rice, weeds are progressively being eliminated to great extent through introduction of new herbicides; however, the issue of unfilled grains is still elusive. As potassium (K) deficiency produce sterile pollens in different crops, therefore possible K deficiency in aerobic rice production system may increase unfilled grains in rice. Therefore, it was hypothesized that K application may yield better by improving grain filling of basmati rice, especially, under aerobic conditions. Pot and field experiments were comprised of no K as control, K fertilization using 90 and 180 kg ha-1 keeping recommended N, P and Zn fertilization at the rate of 180, 125 and 25 kg ha-1. Two fine grain rice cultivars Basmati-515 and Super basmati were used due to their differential response to K fertilization. Results indicated that application of 180 kg K2O ha -1 significantly increased the K concentration in shoot, which increased the paddy yield. Highest chlorophyll contents were observed for Basmati-515 in aerobic rice and for Super basmati under flooded condition at 180 kg K2O ha -1. Decrease in number of un-filled grains may a contributory to paddy yield improvement in K fertilized treatments. The improvement in yield was more pronounced in Basmati-515 than Super basmati. Economic analysis showed higher benefit cost ratio for Basmati-515 with 90 kg Kg ha-1 under aerobic conditions. Net benefit of K fertilization was increased for both fertilizer rates and both cultivars except 180 kg K in Super basmati. As K fertilization increased the number of filled grains and improved the rice yield, therefore it is suggested to apply K fertilizers for better yield and expanded adaptability of aerobic rice production system for basmati rice. Availability of indigenous soil K under aerobic and flooded conditions should be quantified to develop precise K recommendations for both production systems of basmati rice.

Progress and Prospects for Micronutrient Biofortification in Rice/Wheat

Abstract With recent developments in phenotyping and genetics tools, biofortification programs around the world have significantly contributed to reducing malnourishment, particularly of iron (Fe) and zinc (Zn), in populations that depend upon on cereals as staple foods. As a polygenic trait, several quantitative trait loci (QTLs) for grain Zn or Fe levels have been mapped in the wild relatives of important crops, and these show a common genetic basis with some orthologous chromosomes in both rice and wheat, and with a few positively transgressed. Rice and wheat cultivars with target levels of grain Fe and Zn have been developed and released commercially. However, integration of agronomic biofortification with transgenic approaches and mapping for variation in density of Fe and Zn within endosperm for enhanced bioavailability and stability of traits in different environments are still in progress. Moreover, strategic advocacy for the awareness, demand, and acceptability of studies for scaling up the delivery of biofortified varieties is required to achieve additional health benefits globally.

Incorporation of rice straw mitigates CH4 and N2O emissions in water saving paddy fields of Central Vietnam

ABSTRACT This study evaluated the effects of rice straw and water regimes on CH4 and N2O emissions from paddy fields for two rice growing seasons (summer 2014 and spring 2015). Water regimes included alternating wet–dry irrigation (AWD) maintained at three levels (–5 cm, – 10 cm and –15 cm) in comparison to continuous flooding irrigation (CF). Rice straw (5 t ha–1) was incorporated into the top soil (0 – 15 cm), distributed and burned in situ. Results showed that using burned in situ rice straw was found to reduce seasonal cumulative CH4 emission (24–34% in summer; 18–28% in spring), N2O emission (21–32% in summer; 22–29% in spring) and lower rice yield (8–9%) than rice straw incorporation into top soil. AWD methods reduced the amount of CH4 production (22.6–41.5%) and increased N2O emission (25–26%) without any decrease in rice yield. Rice straw incorporation into the top soil with AWD had higher water productivity (23–37%) than rice straw when burned in situ with CF. The results conclude that AWD and rice straw management can be employed as mitigation strategy for CH4 and N2O emissions from paddy fields in Central Vietnam.

Boron fertilization improves seed yield and harvest index of Camelina sativa L. by affecting source-sink

ABSTRACT The impact of soil (1, 2 kg ha−1) and foliar (100, 200 mg L−1) boron (B) with control (no B) was evaluated on phenology and yield formation of Camelina each applied at stem elongation and flowering stages. Foliar (200 mg L−1) or soil B (2 kg ha−1) resulted in earlier flowering and maturity, increased fruit bearing branches (19.68%), number of siliqua, seeds per siliqua (4.6%), biological yield (15%), seed yield (24%), harvest index (11.4%) and oil contents (23%) than no B. Increased fruit bearing branches, seed filled siliqua or seed numbers, harvest index and oil quality can be attributed to changes in dry matter accumulated of stem with simultaneous increase in siliqua dry weight with foliar or soil applied B. In crux, foliar (200 mg L−1) or soil applied (2 kg ha−1) B seems promising to improve seed and oil yield, harvest index of Camelina sativa under B deficient condition.

Influence of phosphorus application on growth, yield and oil quality of linola

ABSTRACT Influence of different phosphorus (P) sources on growth, yield and oil quality of linola was evaluated when randomized in complete block design using three replications. Treatments were control (No P), hydropriming, soil phosphorus (50 kg ha−1), seed inoculation with phosphate solubilizing bacteria (PSB, Bacillus spp.) and seed priming with single super phosphate (2%) alone and combined with reduced soil phosphorus (25 kg P ha−1). Among treatments, hydropriming and seed inoculation reduced seedling 50% and mean emergence time with highest emergence index, seedling fresh and dry weights and chlorophyll contents. Seed inoculation with soil P (25 kg ha−1) produced highest seeds per capsule, 100-seed weight, seed and biological yield, harvest index. Maximum oil percentage, low protein contents and high cost benefit ratio with net economic returns were also found for seed inoculation combined with soil phosphorus. Nonetheless, soil phosphorus application can be reduced when seed inoculation with PSB is employed.