This study evaluates the potential for adaptability and tolerance of wheat genotypes (G) to an arid environment. We examined the influence of drought stress (DS) (100, 75, and 50% field capacity), planting times (PT) (16-November, 01-December, 16-December and 01-January), and G (Yocoro Rojo, FKAU-10, Faisalabad-08, and Galaxy L-7096) on phenological development, growth indices, grain yield, and water use efficiency of drip-irrigated wheat. Development measured at five phenological growth stages (GS) (tillering, jointing, booting, heading, and maturity) and growth indices 30, 45, 60, and 75 days after sowing (DAS) were also correlated with final grain yield. Tillering occurred earlier in DS plots, to a maximum of 31 days. Days to complete 50% heading and physiological crop maturity were the most susceptible GS that denoted 31-72% reduction in number of days to complete these GS at severe DS. Wheat G grown with severe DS had the shortest grain filling duration. Genotype Fsd-08 presented greater adaptability to studied arid climate and recorded 31, 35, and 38% longer grain filling period as compared with rest of the G at 100-50% field capacity respectively. December sowing mitigated the drought and delayed planting effects by producing superior growth and yield (2162 kg ha(-1)) at severe DS. Genotypes Fsd-08 and L-7096 attained the minimum plant height (36 cm) and the shortest growth cycle (76 days) for January planting with 50% field capacity. At severe DS leaf area index, dry matter accumulation, crop growth rate and net assimilation rate were decreased by 67, 57, 34, and 38% as compared to non stressed plots. Genotypes Fsd-08 and F-10 were the superior ones and secured 14-17% higher grain yield than genotype YR for severely stressed plots. The correlation between crop growth indices and grain yield depicted the highest value (0.58-0.71) at 60-75 DAS. So the major contribution of these growth indices toward grain yield was at the start of reproductive phase. It's clear that booting and grain filling are the most sensitive GS that are severely affected by both drought and delay in planting.

A field experiment was carried out at the Agriculture Experimental Station of King Abdulaziz University during the 2013 and 2014 seasons to study the effect of water regimes and palm coefficient on growth parameters, yield and irrigation water use (IWU) of tissue culture-derived ‘Barhee’ date palm cultivars in a newly established orchard. Four water regimes T1, T2, T3 and T4 representing 70, 85, 100 and 115% of water requirement were studied to select the best water regime that maximizes yield and IWU. Water requirement in 2013 was calculated based on the FAO palm coefficient (Kp) but based on measured Kp during 2014. Results revealed that using measured Kp reduces water requirements in the summer season and increases date yield. It saves about 12% of irrigation water compared to FAO Kp. Increasing the water regime increased yield per palm, where the highest yield was obtained from T4 (16.5 kg per tree), and the least from T1(12.4 kg per tree). IWU is increased by decreasing the water regime. However, the differences between T4 and T3 were not significant, indicating that giving the highest water regime produces the highest yield. It is concluded that increasing water supply maximizes yield production of young tissue culture-derived ‘Barhee’ date palms in a newly established orchard. Copyright © 2016 John Wiley & Sons, Ltd.

Screening of drought tolerant genotypes for arid land cultivation is the best approach to avoid yield losses as breeding and selection are time taking techniques. Current experiment was planned to evaluate late sown wheat cultivars potential for drought tolerance and adaptability in Jeddah region, KSA. Four wheat cultivars (Yocoro, Rojo, Faisalabad-2008, F-10 and L-7096) were tested against drought stress applied as (75% and 50%) of total crop water requirement. A 100% water requirement was also applied as control. Data regarding crop growth stages, growth, grain yield and yield contributors were tested by using MSTAT-C. Drought stress significantly decreased all growth and yield traits except harvest index and the effect of water stress was the most severe where 50% of the total water requirement was applied. Both studied crop growth stages (days to complete tillering and days to complete 50% heading) were also affected to applied water stress and effect was more pronounced for days to complete 50% heading. Studied cultivars responded variably for different growth and yield traits. Cultivar Yoco Rojo took minimum days to complete tillering and heading while L-7096 presented the highest plant height and dry biomass accumulation. Faisalabad-2008 reported maximum values for grain yield and yield contributors except spike length that was maximum in Yocoro Rojo. Based on the field evaluation, it’s concluded that Faisalabad-2008 produced significant results for growth and yield traits among studied cultivars and can be successfully grown in arid land conditions under limited water supplies.

A field experiment was carried out at the Agricultural Experimental Research Station of King Abdulaziz University to study the effect of irrigation level, row spacing and inter-row spacing on productivity and irrigation water productivity (IWP) of Canola. Two irrigation levels, IFull (100% of field capacity) and Imin (65% of IFull), were investigated. Three row spacing, S1, S2 and S3, represented by 20, 40 and 60 cm between rows were studied under each irrigation level. Three inter-row spacing, IRS1, IRS2 and IRS3, represented by 5, 10 and 20 cm between plants, were investigated for each row spacing. Results indicated that Imin reduced seed yield per plant, total seed yield and oil percentage but increased IWP. Decreasing row and inter-row spacing decreased seed yield per plant but increased total seed yield and IWP. The highest oil percentage (36.1%) was obtained from S2 during both growing seasons. The triple interaction optimized total seed yield, IWP and oil production. The best combination was IFull–S1–IRS2 with average production of 8430 kg ha
1 seed yield which is expected to produce 2990 kg of oil, followed by Imin–S1–IRS1 which produced 6750 kg ha
1seed yield with about 2270 kg ha
1of oil. Application of this combination saves 35% of water but reduces oil production by 24%. Copyright © 2016 John Wiley & Sons, Ltd.

A field experiment was conducted in 2011 and 2012 to study the effect of fertigation on yield, fruit quality and nutrient uptake of ‘Nabbut-Ahmar’ date palm cultivar grown in sandy loam soil. Three fertigation treatments were compared with traditional application. In traditional treatment (CT), the recommended dose [2300 g nitrogen (N), 1200 g phosphorus (P) and 1400 g/ tree] was applied as a soil broadcast in three equal doses. The fertigation treatments, (T2), (T3) and (T4), represent all nitrogen, phosphorus and potassium (NPK) amounts of CT, 2/3 CT and 1/3 CT, respectively that were injected in twelve equal doses. The results showed that compared to CT, the fertigation treatments increased yield/palm by 41%, 31% and 18% for T3, T2 and T4, respectively. Beside the increase in yield, 33% and 66% of the applied fertilizers were saved by T3 and T4, respectively, compared with CT. Feritgation treatments had no negative impact on the overall fruit quality characteristics and even increased total soluble solids (TSS), soluble tannins and total phenols concentrations compared to the conventional fertilization. Availability of NPK increased by fertigation but without further increase in leaves and fruit. In conclusion applying 2/3 of the recommended dose of NPK fertilizers under dry land condition through fertigation maximize yield, quality and fertilizer use efficiency.

Screening of drought tolerant genotypes for arid land cultivation is the best approach to avoid yield losses as breeding and selection are time taking techniques. A current experiment was planned to evaluate late sown wheat cultivars potential for drought tolerance and adaptability in Jeddah region, KSA. Four wheat cultivars (YocoroRojo [YR], Faisalabad-2008, F-10 and L-7096) were tested against drought stress applied as (75% and 50%) of total crop water requirement. A 100% water requirement was also applied as a control. Data regarding crop growth stages, growth, grain yield, and yield contributors were tested using MSTAT-C. Drought stress significantly decreased all growth and yield traits except harvest index, and the effect of water stress was the most severe where 50% of the total water requirement was applied. Both studied crop growth stages (days to complete tillering and days to complete 50% heading) were also affected to applied water stress and effect was a more pronounced for days to complete 50% heading. Studied cultivars responded variably for different growth and yield traits. Cultivar YR took minimum days to complete tillering and heading while L-7096 presented the highest plant height and dry biomass accumulation. Faisalabad-2008 reported maximum values for grain yield and yield contributors except spike length that was maximum in YR. Based on the field evaluation, it is concluded that Faisalabad-2008 produced significant results for growth and yield traits among studied cultivars and can be successfully grown in arid land conditions under limited water supplies.

Understanding the critical period of weed competition is indispensable in the development of an effective weed management program in field crops. Current experiment was planned to evaluate the critical growth period of Setaria and level of yield losses associated with delay in weeding in rain-fed drip irrigated wheat production system of Saudi Arabia. Field experiment was conducted to evaluate the effect of weeding interval (07-21, 14-28, 21-35, 28-42 and 35-49 days after sowing) and drought stress (75% and 50% of field capacity) on Setaria growth, wheat yield and water use efficiency. Season long weedy check and wellwatered (100% FC) plots were also maintained for comparison. Weeding interval and drought stress significantly (p ≤ 0.05) affected the growth and yield of Setaria and wheat. Drought stress from 75% to 50% FC resulted in reductions of 29-40% in Setaria height, 14-27% in Setaria density and 11-26% in Setaria dry biomass. All weeding intervals except 35-49 DAS significantly suppressed Setaria growth as compared with control. Delay in weeding increased weed-crop competition interval and reduced wheat yield and yield contributors. Therefore, the lowest yield of 1836 kg ha-1 was attained for weeding interval of 35-49 DAS at 50% FC. Water use efficiency and harvest index increased with decreasing FC levels but reduced with delay in weeding. Correlation analysis predicted negative association of Setaria density with wheat yield and yield contributors and the highest negative association was for harvest index (-0.913) and water use efficiency (-0.614). Early management of Setaria is imperative for successful wheat production otherwise yield losses are beyond economical limits.

tA field experiment was conducted during 2013 and 2014 seasons to compare fertigation and conventionalsoil broadcast fertilization on growth, yield, fruit quality and nutrient uptake of tissue culture-regenerated‘Barhee’ date palm grown in sandy loam calcareous soil in a newly established orchard. In the conventionaltreatment (CT), the recommended dose (450 g N, 225 g P and 225 K g/tree) was applied as a soil broad-cast in three equal doses. In the fertigation treatments, the NPK fertilizers were injected with irrigationwater in 12 equal doses, (T2), (T3) and (T4), represent all NPK amounts of CT, 2/3 CT and 1/3 CT, respec-tively. The highest fertilization regime either applied as soil broadcast or as fertigation produced thehighest total yield per palm compared with other fertigation treatments. However, fruit physical qualityparameters were higher at T3 and T4 than other treatments. On the other hand, fruit biochemical qualitycharacteristics showed unspecific trend. Palm growth parameters, chlorophyll a, b, and total chlorophyllsconcentration as well as chlorophyll a/b ratio were not affected by the fertilization treatments. The CT andthe fertigation treatments T2 and T3 increased nitrogen availability without, however, a further increasein leaves, except for T2. At the end of the sixth growing season (third flowering season from transplan-ting), all the cultivated ‘Barhee’ palms were rapidly and strongly growing without any losses in all thetreatments. However, some flowering abnormalities were observed such as multiple carpels formation, arelatively low fruit set percentage and albinism that were lower in 2014 than 2013 season. In conclusion,fertilization is critical to increase yield of young tissue culture-regenerated palms which might have arelatively high nutrient demand.

Field experiment was conducted to optimize forage production and water use efficiency (WUE) under dry land condition at the Agriculture Research Station of King Abdulaziz University located at Hada Al-Sham, Jeddah. Aim of the research was to produce the optimum forage production with the least amount of irrigation water in alfalfa and blue panic forage crops. To fulfill the above mentioned objective three irrigation systems (sprinkler, drip and sub-surface drip) were investigated using three water regimes namely: 100% water requirement (WR), 75%WR and 50 % WR. Under these treatments alfalfa and blue panic crops were investigated. Results revealed that, total water supply was increased along the growing season to reach its maximum in June, then decreased. Sub-surface drip produced the highest forage yield under fully water requirement (100% WR). Surface drip increased yield production under stress treatments (75% WR and 50% WR) while sprinkler system produced the least forage yield. Under fully and stress treatments, blue panic produced higher forage yield than alfalfa. WUE was the best under subsurface drip followed by surface drip while the least was recorded in sprinkler irrigation.

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