This study aims to compare the effects of different laser wavelengths, exposure times, and low-power-intensity laser irradiation on maize seeds. Seeds were exposed to He–Ne (632.8 nm) red laser, Nd:YAG second-harmonic-generation (532 nm) green laser, and diode (410 nm) blue laser. Four different exposure times (45, 65, 85, and 105 s) with different intensity (2 and 4 mW/cm2), for each laser were tested. Phenology and yield components (plant height, leaf area, number of rows per ear, seed yield, harvest index, yield efficiency, and grain weight) were determined. The experiment was conducted in a randomized complete block design with three replications. Plant height was found comparatively high in blue laser light—211 cm at 85 s. Blue and green laser lights showed significant increases in the number of rows per ear to 39.1 at 85 s and 45 at 65 s, respectively, compared to the control of 36 rows/ear. The order of seed yield was blue (7003.4 kg/ha) > green (6667.8 kg/ha) > red (6568.01 t/ha) based on different exposure times of 85 s, 85 s, and 105 s, respectively, compared to the control of 6.9 kg/ha. The findings indicate the possibility of using blue laser light to manipulate the growth and yield of maize.

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An experiment was carried out in the Laboratory of Seed Technology-College of Agricultural Engineering Sciences - University of Baghdad – Iraq, to studying the stimulation of maize seeds by soaking with selenium and chitosan to improve the vigour and viability of seeds. By using factorial experiment according to the Complete Random Design (CRD) with three replications. The seeds of two synthetic cultivars of maize (Baghdad 3 and Buhoth 5018) were soaked in selenium solutions at two concentrations (2 and 5 mg L-1), and chitosan (100 and 500 mg L-1) for 10 hours, as well as the two control treatments, which were dried seeds (without soaking) and the seeds soaked in distilled water. Results are shown that low concentration of 2 mg L-1 give highest mean were recorded in the percentage of germination in the first and final counts, the mean time germination, length of root and the plumule, the seedling vigour index, germination speed, and dry weight of the seedling. Seeds soaking with the solutions containing chitosan at both concentrations did not give significant results compared to the selenium treatments, both cultivars differed significantly in some germination characteristics and the vigour and viability of the seed: (length of root and the plumule, dry weight of the seedling). The results also showed a significant effect of the interaction between seed soaking treatments and cultivar on all studied traits. We conclude from this study that treatments of stimulating seeds by soaking them with distilled water and solutions of selenium and chitosan positively affected germination and its characteristics, so we recommend using low concentrations of selenium and chitosan to improve seed germination, vigour, and viability of the seedling.

Background Laser applications in agriculture have recently gained much interest due to improved plant characteristics following laser treatment before the sowing of seeds. In this study, maize seeds were exposed to different levels of laser treatment prior to sowing to improve their field performance. The aim of this study is to evaluate the impact of pre-sowing laser photobiomodulation on the field emergence and growth of treated maize seeds. Methods The maize seeds were first photobiomodulated with two lasers: 1) a helium-neon (He–Ne) red laser (632.8 nm), and 2) a neodymium-doped yttrium aluminum garnet (Nd:YAG) green laser (532 nm). Following three replications of randomized complete block design (RCBD), four irradiation treatments were applied (45 s, 65 s, 85 s, and 105 s) at two power intensities (2 mW/cm2 and 4 mW/cm2). Results Based on the results, maize seeds pretreated with a green laser and 2 mW/cm2 power intensity for 105 s exhibited the highest rate of seed emergence (96%) compared to the untreated control seeds with a lower seed emergence rate (62.5%). Furthermore, maize seeds treated with a red laser for 45 s showed an increased vigor index compared to the other treatment options and the control (P < 0.01). The treatment groups also showed statistically significant differences in seedling growth characteristics compared to the control group p < 0.01. The green laser produced a significant enhancement of about 24.20 cm in seedling length, 8.2 leaves/plant, and 3.4 cm in stem diameter compared to the untreated seeds. Moreover, the green laser treatment showed 57.4 days to anthesis, which was earlier than the untreated seeds (61.4 days). The results showed that the protein, oil, and starch contents of the seeds irradiated with the green laser were 17.54%, 6.18%, and 73.32%, respectively, compared to the seeds irradiated by the red laser with 16.51%, 6.33%, and 71.05%, respectively. Conclusions The photo biomodulation of maize seeds using a green laser light can improve the field emergence, seedling growth, and seed quality of the treated seed compared to the red laser treatment.

Many literatures have reviewed and confirmed the importance of the seaweed extract in terms of improving crop yield. A field experiment was carried out during winter season at Izzah Heuristic Farm in Wasit Province, Iraq to examine the effect of combination of seaweed extract and micronutrient fertiliser on some wheat cultivars. Three cultivars were used in this experiment as well as four stimulator treatments: control (no added extract), seaweed extract, micronutrient, and a combination of both of them. A randomized completely blocked design (RCBD) with a factorial arrangement and three replicates was used in this experiment. The results showed that BHTH cultivar had significantly largest number of spikes, spike length, number of grains per spike, kernel weight and grain yield. The mixture treatment enhanced grain yield of all cultivars was better treatment compared with the others. In terms of the interactions, BHTH cultivars in the mixture treatment had the greatest grain yield and other components. It is clear that a combination of marine algae with micronutrient fertiliser can improve the crop grain yield and its component and can be recommended for farmers to enhance grain production. However, further study might be better step for further exploration about the impact of seaweed extract and micronutrient fertiliser with further rates and other crops or crop cultivars.