Fathy S. El-Nakhlawy

Wheat Phenological Development and Growth Studies As Affected by Drought and Late Season High Temperature Stress under Arid Environment

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. Its clear that booting and grain filling are the most sensitive GS that are severely affected by both drought and delay in planting.

WATER USE EFFICIENCY, GROWTH AND YIELD OF WHEAT CULTIVATED UNDER COMPETITION WITH Setaria

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 ofSetaria 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 suppressedSetaria 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 ofSetariadensity 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.

Estimation of weed dry biomass and grain yield as a function of growth and yield traits under allelopathic weed management in maize

Growing concerns about toxicity and development of resistance against synthetic herbicides have demanded looking for alternative weed management approaches. Allelopathy has gained sufficient support and potential for sustainable weed management. Aqueous extracts of six plant species (sunflower, rice, mulberry, maize, brassica and sorghum) in different combinations alone or in mixture with 75% reduced dose of herbicides were evaluated for two consecutive years under field conditions. A weedy check and S-metolachlor with atrazine (pre emergence) and atrazine alone (post emergence) at recommended rates was included for comparison. Weed dynamics, maize growth indices and yield estimation were done by following standard procedures. All aqueous plant extract combinations suppressed weed growth and biomass. Moreover, the suppressive effect was more pronounced when aqueous plant extracts were supplemented with reduced doses of herbicides. Brassica-sunflower-sorghum combination suppressed weeds by 74-80, 78-70, 65-68% during both years of study that was similar with S-metolachlor along half dose of atrazine and full dose of atrazine alone. Crop growth rate and dry matter accumulation attained peak values of 32.68 and 1,502 g m-2 d-1 for brassica-sunflower-sorghum combination at 60 and 75 days after sowing. Curve fitting regression for growth and yield traits predicted strong positive correlation to grain yield and negative correlation to weed dry biomass under allelopathic weed management in maize crop.

Enhanced mungbean and water productivity under full irrigation and stress using humic acid in arid regions

A field experiment was conducted during 2016 and 2017 seasons at the Agriculture Research Station of King Abdulaziz University at Hada Al-Sham, Saudi Arabia in a split plot design to investigate the response of Mungbean [(Vigna radiate (L.)Wilczek] MN-96 cv. to three irrigation water regimes(100%, 80% and 60% of water requirements)and three humic acid (HA) rates (15, 30 and 45 kg/ha HA) was mixed with the soil surface. Seed yield and yield components were significantly similar under 30 and 45 kg HA/ha. No significantly differences were showed between seed yield/ha, yield components and IWUE under the 80% water regime with45 kg/ha HA and 100% water regime with 15 kg/ha HA.

Evaluation of the Agricultural Value and Germination Vigor of the Introduced Seeds of the Main Crops in Saudi Arabia@@@تقييم القيمة الزراعية وقوة الإنبات للبذور المستوردة للمحاصيل الرئيسية في المملكة العربية السعودية

This investigation was conducted to evaluate the main introduced field and vegetable crop seeds in Saudi Arabia concerning purity, germination, germination vigor and agricultural value. Two cv. were studied from alfalfa, barley, millet, cucumber, pepper and three cv. from tomato. The pure seed percentages were 97.21%, 99.10%, 96.14%, 98.25%, 95.81% and 82.14% for alfalfa Australian-S, alfalfa Cuf 101, barley Gesto, barley Giza-2000, millet Indian and millet African cv., respectively. Purity for vegetable cv. were 98.05%, 96.60%, 98.16%, 96.09%, 98.34%, 99.00% and 98.80%, for cucumber Green Long, cucumber Beit Alfa, pepper California Wonder, pepper Hot Arohein, tomato Super-Strain-B, tomatoes Five Stars and tomato Mormande cv., respectively. Normal seedlings under standard conditions and saline irrigation water stress were 96.67% and 68.94% for alfalfa AustralianS cv. respectively and 94.20% and 60.66% for barley Gesto cv., respectively, while in vegetable crops cucumber Green Long had 86.88% and 42.61%, respectively, pepper Hot Arahein produced 73.64% and 56.67%, respectively and tomato Five Star had 78.68% and 42.17% for normal seedlings (%) under standard conditions and salt stress condition, respectively. Alfalfa Cuf 101 had the highest seed agricultural value (94.38%) and millet African cv. had the lowest agricultural value (62.98%) within the field crop cultivars. In vegetable crops cv., cucumber Beit Alfa cv. had the highest value (87.07%), while pepper Hot Arohein had the lowest agricultural value (70.76%).

Evaluation of the Main Local Field and Vegetable Crops Seeds in the Western Zone of Saudi Arabia

Abstract. Seeds of three local varieties from the field crops i.e. wheat (Baladi, Qassimi and Ucorra Rojo), alfalfa (Mekawi, Hassawi and Sabkhawi) and sesame (Mekawi, Gizan and Taefi) besides one local variety from the vegetable crops, tomatoes (Baladi), cucumber (Baladi) and eggplant (Baladi) were evaluated. Recommended partitioning processings were done on the seed samples to form the purity sample. Purity, moisture, germination and germination vigor tests were done according to ISTA (1993) and AOSA (1996). Purity of the wheat varieties ranged from 95,99% to 97,73% and for alfalfa varieties ranged from 87,89% of Sabkhawi to 92,52% of Makawi. Purity range of sesame varieties was 89,56% for Gizan cv, to 93,65% for Makawi. The highest weed was associated with alfalfa varieties: 5,94% in Hasawi and 5,54% in Sabkhawi varieties. As for vegetable crops varieties, the highest germination appeared in cucumber Baladi variety (98,21%), followed by eggplant Baladi variety (96,5%), then tomatoes Baladi variety (94,55%). Eggplant seeds had the highest weed seeds (0,80%), followed by cucumber (0,51%), then tomatoes (0,21%). As for lab germination test, Qassimi variety produced the highest significant value in wheat varieties (97,50%) and Makawi variety produced the highest value (95%) in alfalfa. In sesame varieties, Makawi variety had the highest germination (93,75%) but the highest abnormal seedling (5%) was produced from Taefi sesame variety, Under the salt stress irrigation, lab germination in wheat varieties ranged from 92,5% for Qassimi to 81,25% for Baladi variety, in alfalfa varieties the range was 87,5% to 82,5% and in sesame 92,25% to 75,75%. As for vegetable crops, the germination percentages were 88,43%, 91,75% and 76,61% for tomatoes, cucumber and eggplant, respectively. Under field conditions, the germination percentages were 62%, 36% and 23% for the previous three vegetable crops, respectively. The moisture content in wheat varieties ranged from 11,58% to 10,21% and in alfalfa from 8% to 7,5%, while in sesame seeds moisture content ranged from 4,9% for Makawi to 4,46% for Taefi variety. Moisture content in vegetable seeds was 8,71%, 7,75% and 7,53% for cucumber, tomatoes and eggplant varieties, respectively.