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Two field experiments were conducted in the experimental station farm, faculty of agriculture, Ain Shams University at Shalakan, Kalubia Governorate, during the two growing seasons, i.e. 2009 and 2010, to investigate the response of growth and forage yield production of pearl millet cv. Shandaweel 1 to nitrogen fertilization rates and cutting height above the soil surface. Four nitrogen rates as ammonium nitrate (33.5%N), 0, 30, 45, and 60 kg N/fed, were arranged in the main plots and two levels of cutting heights (10 and 20 cm above the soil surface) in the subplot with four replicates in split-plot design. In the second season, nitrogen application increased up to 75 kg N/fed. The main results were as follows: Significant increases were appeared in plant height (cm), number of tillers/m 2 , number of leaves/m 2 , and leaf area index during the two growing seasons as nitrogen fertilization rates increased except at the third cut in the first season for plant height (cm) and number of tillers/m 2 , the first and second cuts of the first season for number of leaves/m 2 and at the third cut during the first season of study for leaf area index, while leaf/stem ratio was not affected significantly during the two growing seasons. Green forage yield/fed was significantly increased as nitrogen application rates increased during the two growing seasons except at the third cut of the first season of study. Increasing nitrogen fertilization rates up to 75 kg N/fed caused significant increases in dry forage yield during the three collected cuts in the second season of study and the second cut during the first season of study as well as in the combined results. Plant height (cm) was significantly affected as cutting height above the soil surface increased in the second cut (2009) and the first cut (2010) where plant height increased at 10 cm as cutting height than at 20 cm above the soil surface. Significant differences were appeared in number of tillers/m 2 as cutting height varied from 10 to 20 cm in the two studied seasons. The highest cut of number of tillers/m 2 was scored at 20 cm cutting height than those at 10 cm in the second and third cuts during the two growing seasons. A number of leaves/m 2 as well as leaf area index were influenced significantly as cutting height increased during the two growing seasons except in the second and third cuts during 2009 or the third cut during 2010 for number of leaves/m 2 and in the second cut of the first season (2009) and the third cut during 2010 for leaf area index. Significant effects were noticed in leaf/stem ratio as cutting height differed in the second or third cut in 2009 and in the three collected cuts in combined analysis. Green forage yield, dry forage yield/feddan increase significantly as cutting height differed during the two growing seasons as well as the combined results except in the first cut during the first season of study for dry forage yield. Green forage yield as well as dry forage yield was significantly affected by the interaction between nitrogen ferti...

Cysteine (Cys) and α-lipoic acid (ALA) are naturally occurring antioxidants (sulfur-containing compounds) that can protect plants against a wide spectrum of environmental stresses. However, up to now, there are no conclusive data on their integrative roles in mitigation of drought stress in wheat plants. Here, we studied the influence of ALA at 0.02 mM (grain dipping pre-cultivation treatment) and Cys (25 and 50 ppm as a foliar application) under well watered and deficit irrigation (100% and 70% of recommended dose). The results showed that deficit irrigation markedly caused obvious cellular oxidative damage as indicated by elevating the malondialdehyde (MDA) and hydrogen peroxide content (H2O2). Moreover, water stressed plants exhibited multiple changes in physiological metabolism, which affected the quantitative and qualitative variables of grain yield. The enzymatic antioxidants, including superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POX) were improved by Cys application. SOD and APX had the same response when treated with ALA, but CAT and POX did not. Moreover, both studied molecules stimulated chlorophyll (Chl) and osmolytes’ biosynthesis. In contrast, the Chl a/b ratio was decreased, while flavonoids were not affected by either of the examined molecules. Interestingly, all above-mentioned changes were associated with an improvement in the scavenging capacity of reactive oxygen species (ROS), leaf relative water content (RWC), grain number, total grain yield, weight of 1000 kernels, gluten index, falling number, and alveographic parameters (P, W, and P/L values). Furthermore, heatmap plot analysis revealed several significant correlations between different studied parameters, which may explore the importance of applied Cys and ALA as effective compounds in wheat cultivation under water deficit conditions.

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Abiotic stresses represent a major impediment to crop productivity, especially in arid regions. Thus, over two years of 2014 and 2015, a field experiment was undertaken at El Nubaria region, Egypt to assess the productivity and water use efficiency (WUE) of sunflower as affected by planting dates (April 21, May 21, and June 21) and irrigation levels (ET100%, ET85% and ET70%,). Results clarified that leaf chlorophyll a content was higher by sowing in May than in either April or June sowings, while leaf carotenoides of plant sown in May or June surpassed those sown in April. The minimal value of proline was obtained with sowing in May. Sowing in May increased plant height by 52.2 and 22.3 as well as LAI by 19.3 and 73.1% than sowing in April and June, respectively. The reductions in seed yield, oil yield and WUE amounted to 10.5 and 12.8, 13.7 and 18.3 as well as 11.8 and 9.8 % with April and June sowings, respectively, compared to May sowing. ET100% showed superiority over than ET85% and ET70% in improving sunflower yields and its attributes, but WUE did not affect. Sunflower sown in May and irrigated with ET100% gave the maximum values of seed yield and its attributes and WUE surpassing other interaction treatments. In June, WUE value increased under severe water deficit i.e. ET70% comparing to moderately water-stressed (ET85%) or well-watered conditions (ET100%).

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Agricultural water rationalization expressed in irrigating the plants below their requirements became a significant strategy in crop water management. However, reduction in crop productivity under low water supply is realized. Therefore, the current study aimed to diminish sunflower yield losses associated with deficit irrigation using salicylic acid (SA). During two seasons of 2019 and 2020 at El Nubaria region, El Behaira Governorate, Egypt, combinations of three irrigation regimes (100, 85 and 70% of crop evapotranspiration, denoted WR100%, WR85%, and WR70%, respectively), and three levels of SA (0.0, 0.5, and 1 mM. abbreviated as SA0.0, SA0.5, and SA1.0, respectively) on sunflower plants performance were evaluated. Treatments were arranged in a strip–plot design with three replicates. Findings revealed that treated sunflower plants with WR100% × SA1.0 contained the highest amounts of total chlorophyll and carotenoids as well as the lowest proline content. Seed yield of WR100% × SA1.0 treatment was higher than that of WR70% × SA0.0 by 109.7% in the first season and 125.9% in the second one. As averages of the two seasons, SA0.5 and SA1.0 lowered the reductions in seed yield from 21.0% to 15.8 and 14.4% as well as 46.2% to 40.8 and 40.1% under WR85% and WR70%, respectively, compared to the farmer common practice (WR100% × SA0.0). WR100% × SA1.0 for iodine value as well as WR100% × SA1.0 and WR100% × SA0.5 for seed oil % were recorded the highest. Application of WR100% × SA1.0 and WR100% × SA0.5 were the effective combinations for ameliorating water use efficiency. In conclusion, involving salicylic acid in irrigation programs of sunflower became a decisive action to save water and alleviate the yield losses resulting from drought stress.