Evaluation of grain yield indices in hexaploid wheat genotypes in response to drought stress

Drought stress limits crop production in the world. Therefore, employing high-yielding cultivars tolerant to drought is an effective approach to reduce its detrimental effects. To identify drought-tolerant genotypes, 36 wheat genotypes were evaluated during the 2010–2011 and 2011–2012 growth seasons. A field experiment was conducted in a split-plot design with two irrigation treatments (100% field capacity (FC) until harvest and no irrigation after anthesis) as main plots in three replications and genotypes as subplots. Grain yield, its components and drought tolerance indices were measured. Results showed a significant reduction in yield and its components under drought conditions. Grain yield had significant positive correlations with stress tolerance index (STI), mean productivity (MP) index and geometric mean productivity (GMP), while it was negatively correlated with stress susceptibility index (SSI) and tolerance index (TOL) under stress condition. These results indicated that superior genotypes could be selected based on high values of STI, MP and GMP and low value of SSI. The results were validated by principal component analysis (PCA) as it showed genotypes with high PC1 and low PC2 were more desirable. Based on the results, genotypes number 8, 11, 17, 30, 34 and 35 were recognized as suitable for both conditions.     

Evaluation for heat stress tolerance in durum wheat genotypes using stress tolerance indices

Heat stress is a major environmental stress limiting wheat productivity in most cereal growing areas of the world. The objective of this study was to evaluate heat stress tolerance in durum wheat (Triticum turgidum var. durum) genotypes. For this purpose, 45 genotypes were grown during two growing seasons (2012–2013 and 2013–2014) under non-stress (normal sowing) and heat-stress (late sowing) conditions. The heat tolerance indices were calculated based on grain yield under normal sowing (Yp) and late sowing (Ys) conditions. Results of combined analysis of variance showed the significant influences of heat stress on grain yield as well as significant differences among genotypes for grain yield and the indices. Results of correlation coefficients and multivariate analyses revealed that the stress tolerance index (STI), geometric mean productivity and mean productivity (MP) indices were the most profitable criteria for selection of heat tolerant and high yielding genotypes. Using STI, GMP and MP, the genotypes G29, G41 and G10 were found to be the best genotypes with relatively high yield and suitable for both normal and heat stressed conditions. Based on biplot analysis using Yp, Ys and the indices, it was possible to identify superior genotypes across the conditions.     

Genetic properties of drought tolerance indices in sunflower

Abstract

The objective of the present study was genetic analysis of yield-based drought tolerance indices using the diallel method. Twenty-one genotypes of sunflower (Helianthus annuus L.) derived from a half diallel cross between six inbred lines were evaluated in both stress and non-stress conditions using a randomized complete block design for each one. Eight drought tolerance indices comprising stress tolerance index (STI), mean productivity (MP), geometric mean productivity (GMP), harmonic mean (HM), stress susceptibility index (SSI), tolerance index (TOL), yield index (YI) and yield stability index (YSI) were calculated based on grain yield under stress and non-stress environments. Significant genotypic differences were observed in TOL, GMP, MPSTI, HM and YI. Diallel analyses revealed the importance of both additive and non-additive gene effects in GMP, STI, HM and YI. However, the Baker ratio supported the predominance of an additive effect in their expression. Our results demonstrated that SSI, YSI, TOL and MP are not reliable indices to select drought tolerant genotypes in sunflower breeding programmes because of their low heritability. Indices such as GMP, STI, HM and YI were moderately heritable and are usually able to select high-yielding genotypes in both environments and could be usefully employed in drought tolerance breeding programmes of sunflower.     

Evaluation of bread wheat (Triticum aestivum L.) genotypes for yield and related traits under drought stress conditions

ABSTRACT

Drought is a major factor threatening crop production worldwide. Developing wheat varieties that are adapted to drought prone environments is a sustainable strategy to improve wheat production and productivity. The aim of this study was to evaluate and select bread wheat genotypes for yield and yield components, and for stability under drought stress and non-stress conditions. One hundred and twenty genotypes were evaluated at five test sites in the 2018/19 cropping season using a 10 x 12 alpha lattice design with two replicates. The level of drought stress was imposed using different sowing dates (early planting representing non-stressed, while late planting as drought stressed conditions) following the onset of the main rain at each site. Grain yield and yield components were recorded, and drought indices were calculated for each genotype. Among the drought tolerance indices, GMP, MP, HM, STI and YI were found to be the most suitable for predicting drought tolerance because they had significant and positive correlations with yield under drought stress and non-stress conditions. Rank sum analysis identified the most drought tolerant genotypes as ‘YS-34', ‘YS-85' and ‘YS-82’. The selected wheat genotypes are useful genetic resources for future drought tolerance breeding programmes in Ethiopia or similar agro-ecologies.     

Root system response of selected lowland Thai rice varieties as affected by cultivation method and potassium rate under alternate wetting and drying irrigation

ABSTRACT

Root system is an important factor for crop productivity under water- and nutrient-limited environments. A pot study was conducted to evaluate root system response of three Thai rice varieties (Pathumthani 1, RD57, RD41) under three cultivation methods (dry direct seeding [DDS], wet direct seeding [WDS], transplanting [TP]) and three levels of alternate wetting and drying irrigation (–5, –15, –30 kPa). A second pot experiment examined the effect of potassium (K) rates (0, 80, 120, 160 kg ha^–1) on root system response of the same varieties under DDS and TP subjected to alternate wetting and drying at –5 kPa. Pathumthani 1 was more tolerant to moisture stress; RD57 and RD41 showed an inconsistent response to moisture-deficit conditions. Rice plant under TP was more sensitive to moisture stress; rice plant performed better under DDS even at the highest soil moisture stress of –30 kPa. K application at the rate of 120 kg ha^–1 as basal under DDS was optimum for root system development of Pathumthani 1, while RD57 and RD41 had higher actual root length at the same K rate regardless of cultivation methods. Alternate wetting and drying up to –30 kPa could be safely applied for the three tested varieties. The performance of root system of Pathumthani 1 was better under DDS method of cultivation. K fertilization at 120 kg ha^–1 can be recommended as optimum rate under water-saving cultivation techniques for the three tested varieties.     

Reduced trigonelline accumulation due to rhizobial activity improves grain yield in peanut (Arachis hypogaea L.)

Abstract

Crop improvement for drought tolerance is critical for the future of crop production. The objectives were to examine the relationship between trigonelline (TRG) accumulation and yield traits in 10 peanut (Arachis hypogaea L.) genotypes inoculated with two commonly used nitrogen-fixing Rhizobium spp., and to evaluate a role of TRG on growth traits. TRG increased as a defensive metabolite in response to water deficit, but resulted in the reduction of the number of nodules and yield. Symbiotic rhizobial activity helped plants to improve yield particularly in a fully irrigated field rather than under reduced irrigation. TRG concentrations in genotypes (7 out of 10) increased under reduced irrigation as compared with those under full irrigation in two years. Mean number of nodules at maturity (120 days after planting) across genotypes under reduced irrigation were 89 in the control, 111 in Lift, and 161 in Histick treatments, among which Histick was significant (p < 0.05) for nodulation. Mean pod yields in the control, Histick, and Lift treatments were 1.69, 2.34 and 1.87 Mg ha^-1, respectively, under reduced irrigation. Under full irrigation, pod yields were 3.35 in the control, 4.50 in Histick and 3.41 Mg ha^-1 in Lift treatments, but were more significantly improved as treated with Histick than other treatments. Genotype ICGS-76 produced the highest pod yield (5.13 Mg ha^-1) as treated with Histick. All genotypes treated with Histick and Lift biosynthesized less TRG (decreased from 5.8 to 65.3% relative to the control) but produced larger numbers of pods (increased from 9.2 to 80.4% relative to the control), which resulted in substantially higher pod yields.     

Evaluation of Water–Nitrogen Schemes for Rice in Iran,Using ORYZA2000 Model

The model ORYZA2000 simulates the growth and development of rice under conditions of potential production and water and nitrogen (N) limitations. Crop simulation models could provide an alternative, less time-consuming, and inexpensive means of determining the optimum crop N and irrigation requirements under varied irrigation and nitrogen conditions. Water productivity (WP) is a concept of partial productivity and denotes the amount or value of product over volume or value of water used. For the evaluated ORYZA2000 model in Iran, a study was carried out in a randomized complete block design between 2005 and 2007, with three replications at the Rice Research Institute of Iran, Rasht. Irrigation management (three regimes) was the main plot and N application (four levels) was the subplot. In this study, simulation modeling was used to quantify water productivity and water balance components of water and nitrogen interactions in rice. Evaluation simulated and measured total aboveground biomass and yield, by adjusted coefficient of correlation, T test of means, and absolute and normalized root mean square errors (RMSE). Results showed that with normalized root mean square errors (RMSE_n) of 5–28%, ORYZA2000 satisfactorily simulated crop biomass and yield that strongly varied among irrigation and nitrogen fertilizer conditions. Yield was simulated with an RMSE of 237–443 kg ha^?1 and a normalized RMSE of 5–11%. Results showed that the significant (28–56%) share of evaporation into evapotranspiration, using the actual yield (measured) and simulated water balance (ORYZA2000), the calculated average WP_ET was significantly lower than the average WP_T: 37%. The average WP_I, WP_I+R, WP_ET, WP_T, and WP_ETQ were 1.4, 1.07, 1.07, 1.57, and 0.82 kg m^?3. Results also showed that irrigation with 8-day intervals and 60 kg N ha^?1, nitrogen level was the optimum irrigation regime and nitrogen level.     

Screening drought-tolerant genotypes in bread wheat (Triticum aestivum L.) using different multivariate methods

Wheat (Triticum aestivum L.) is one of the most widely cultivated crops in rainfed areas of Iran, where drought is the main limiting factor on yield. The object of this study was the identification of drought-tolerant genotypes in bread wheat. Forty bread wheat genotypes were tested in separate experiments under drought stress and normal conditions in two years (2009–2010 and 2010–2011). Nine drought-tolerance/susceptibility indices including stress susceptibility index (SSI), mean productivity (MP), tolerance (TOL), stress tolerance index (STI), geometric mean productivity (GMP), yield index (YI), yield stability index (YSI), linear regression coefficient (β) and drought response index (DRI) were determined. Simultanously applied factor analysis used two factors instead of nine indices in this study. Mahdavi was recognized as the most drought-tolerant genotype in both years based on factor analysis. In this study an equation was developed for estimating the Stress Tolerance Score (STS). The results of the equation were identical to those of factor analysis in both years. The equation was much easier to use than factor analysis and is suggested as a screening tool for the identification of drought-tolerant genotypes. In this study, Mahdavi was the most drought-tolerant genotype also corresponding to this equation.     

Combined effect of deficit irrigation and potassium fertilizer on physiological response,plant water status and yield of soybean in calcareous soil

A 2-year field experiment (2013 and 2014) was conducted in calcareous soil (CaCO₃ 19.2%), on soybean grown under three irrigation regimes 100%, 85% and 70% of crop evapotranspiration combined with three potassium (K₂O) levels (90, 120 and 150 kg ha^?1). The objective was to investigate the complementary properties of potassium fertilizer in improving soybean physiological response under water deficit. Plant water status (relative water content RWC, chlorophyll fluorescence F_v/F₀ and F_v/F_m), had been significantly affected by irrigation or/and potassium application. Potassium improved growth characteristics (i.e. shoot length, number, leaf area and dry weight of leaves) as well as physiochemical attributes (total soluble sugars, free proline and contents of N, P, K, Ca and Na). Yield and yield water use efficiency (Y-WUE) were significantly affected by irrigation and potassium treatments. Results indicated that potassium application of 150 and 120 kg ha^?1 significantly increased seed yield by 29.6% and 13.89%, respectively, compared with 90 kg ha^?1 as average for two seasons. It was concluded that application of higher levels of potassium fertilizer in arid environment improves plant water status as well as growth and yield of soybean under water stress.     

Variation in Yield,Phosphorus Uptake,and Physiological Efficiency of Wheat Genotypes at Adequate and Stress Phosphorus Levels in Soil

Genetic differences among crop genotypes can be exploited for identification of genotypes more suited to a low‐input agricultural system. Twenty wheat (Triticum aestivum L.) genotypes were evaluated for their differential yield response, phosphorus (P) uptake in grain and straw, and P‐use efficiency at the zero‐P control and 52 kg P ha^?1 rates. Substantial and significant differences were obvious among genotypes for both grain and straw yields at stress (8 mg P kg^?1 soil, native soil P, no P addition) and adequate (52 kg P ha^?1) P levels. Genotype 5039 produced maximum grain yield at both P levels. Relative reduction in grain yield due to P‐deficiency stress [i.e., P stress factor (PSF)] ranged between none and 32.4%, indicating differential P requirement of these genotypes. Pasban 90, Pitic 62, Rohtas 90, Punjab 85, and line 4943 did not respond to P application and exhibited high relative yield compared to those at adequate P level. FSD 83 exhibited the best response to P with maximum value for PSF (32.4%). Genotypes were distributed into nine groups on the basis of relationship between grain yield and total P uptake. Rohtas 90 and lines 4072 and 5039 exhibited high grain yield and medium P uptake (HGY‐MP). However, line 5039 with high total index score utilized less P (12.2 kg P ha^?1) than line 4072 and Rohtas 90 (13.5 and 13.6 kg P ha^?1, respectively). Moreover, this genotype also had greater P harvest index (PHI, %) and P physiological efficiency index (PPEI) at stress P level. Pasban 90, Pitic 62, and Pak 81 had the greatest total index score (21), mainly due to high total P uptake, but yielded less grain than lines 5039 and 4072 under low available P conditions. Line 6142 had minimum total index score (15) and also produced minimum grain yield. A wide range of significant differences in PPEI (211 to 365 kg grain kg^?1 P absorbed at stress and 206 to 325 kg grain kg^?1 P absorbed by aboveground plant material at adequate P) indicated differential utilization of absorbed P by these genotypes for grain production at both P levels. It is concluded from the results that wheat genotypes differed considerably in terms of their P requirements for growth and response to P application. The findings suggest that PSF, PHI, and PPEI parameters could be useful to determine P‐deficiency stress tolerance in wheat.     

Irrigation and Nitrogen Fertilization Effects on Soil Chemical Properties and Cotton Yield

A 2-year field experiment was conducted in central Greece (Platykampos, Larissa) to investigate productivity parameters of cotton under conditions of water stress. A Latin square split-plot design with three replications was used to evaluate the effect of three irrigation levels (250, 350, and 450 mm) and three fertilization rates (60, 110, and 160 kg N ha^–1), where irrigation level was the whole-plot factor and the fertilizer was the split-plot factor. The results showed that irrigation level had no significant effect on soil chemical properties, but these only changed with fertilizer application. Concentration of soil nitrates increased in proportion to the amount of applied fertilizer in early July. The associated rise in electrical conductivity (EC) was not sufficiently high as to adversely affect salt-tolerant cotton. The soil acidity produced during formation of nitrate was evident by a soil pH decrease of 0.2 units in the high fertilizer application. A great decline of nitrate N and EC and a rise of pH in all treatments in early August indicated rapid N uptake by the crop during the late stage of vegetative growth. In contrast, cotton yield was not affected by the rate of fertilizer application but by the level of irrigation. This is the reason that correlations between soil properties and yield were insignificant in early July and August. It appears that there was sufficient N available to the crop from sources other than fertilizer N (soil-derived N and irrigation N). Preplant soil nitrates were greater than residual nitrates in the second growing season and indicated depletion of soil mineral N pools of the order of 36 kg N ha^–1 in the 0- to 25-cm depth. Significant negative correlations between soil properties and cotton yield appeared only at the end of the season and indicated that depletion of soil mineral N increased with increasing crop N requirement or irrigation level.     

Effects of Irrigation and Nitrogen Rates on Growth,Yield, and Quality of Muskmelon in Semiarid Regions

Abstract

Muskmelon (Cucumis melo L. cv. ‘Polidor’) were grown under field conditions to investigate the effects of different nitrogen (N) levels (0, 40, 80, and 120 kg ha^{? 1}) on plant growth, water use efficiency, fruit yield and quality (weight, sizes, and water-soluble dry matter), leaf relative water content, and macro nutrition under three different irrigation regimes. Irrigation was applied based on cumulative class A pan evaporation (Ep). Plant treatments were as follows: (1) well-watered treatment (C) received 100% replenishment of Ep on a daily basis, (2) water-stressed treatment (WS) received 75% replenishment of Ep at three-day intervals, and (3) severely water-stressed (SWS): treatment received 50% replenishment of Ep at six- day intervals. Plants grown under C at 120 kg N ha^{? 1} produced significantly higher biomass (175.6 g plant^{? 1}), fruit yield (36.05 t ha^{? 1}), fruit weight (2.25 kg fruit^{? 1}), and leaf relative water content (93.5%) under increasing N levels than did the two deficit irrigation treatments. The WS or SWS treatments caused reductions in all parameters measured except water-soluble dry matter (SDM) concentrations in fruits compared with those receiving unstressed (C) treatment. The WS irrigation regime with 80 kg ha^{? 1} N significantly improved the fruit yield and size, plant dry matter, leaf area, and IWUE compared with the SWS regime. Increased N significantly enhanced foliar N in the unstressed plants. Increasing N rate in the SWS treatment did not increase fruit yield with the same trend found in the WS and C treatments with increasing N levels. The yield reduction under severe water shortage was much more severe at high N rates. Water use (ET) at the C treatment at 120 kg ha^{? 1} N ranged between 160 and 165 cm, while SWS reduced ET to 90 cm at 0 and 40 kg ha^{? 1} N. Nitrogen supply modified water use at C and WS irrigation regimes. Muskmelon yield response to N rate was quadratic and differed with the level of irrigation. This moderate water deficit (SW) may be an alternative irrigation choice with a suitable N application rate for muskmelon growers in arid and semi-arid regions if the goal is to irrigate an agricultural area with limited water supply for more growers, but not if it is maximizing economic yield. Growers should accept a significant yield reduction in exchange for water conservation.     

Yield-based selection indices for drought tolerance evaluation in selected bottle gourd [Lagenaria siceraria (Molina) Standl.] landraces

Bottle gourd is an important crop in arid and semi-arid tropics where recurrent drought is the major constraint to crop production. Identification of drought-tolerant bottle gourd genotypes is fundamental to enhance productivity and for effective breeding and conservation. The objective of this study was to determine drought tolerance of a diverse set of bottle gourd landraces and to identify promising genotypes for direct production or breeding. A field study was conducted using a 12?×?2 factorial experiment involving 12 bottle gourd landraces under drought-stressed (DS) and non-stressed (NS) conditions. Significant differences were observed among bottle gourd landraces with respect to fruit yield under DS and NS conditions. The mean fruit yield under DS and NS conditions was 8.75 and 22.4?t?ha^?1, respectively. Drought stress reduced fruit yield by 62%. Correlation and principal component analyses revealed the significance of yield-based indices of drought tolerance, such as tolerance index, geometric mean productivity, stress tolerance, mean productivity, yield index and harmonic mean, which allowed discrimination of drought-tolerant bottle gourd landraces. Such landraces as BG-79, BG-31, BG-67, BG-52, BG-78 and GC were identified useful for drought tolerance breeding or rootstock development programs.     

Effects of Water Stress and Nitrogen Fertilizer on Multi-Cut Forage Pearl Millet Yield,Nitrogen, and Water Use Efficiency

Forage pearl millet (Pennisetum americanum var. Nutrifeed) is a new forage crop in Iran. A field experiment was conducted at the University of Tehran to evaluate the response of pearl millet to four nitrogen (N) levels (0, 75, 150, and 225 kg N ha^?1) and four irrigation regimes (40%, 60%, 80%, and 100% of available soil water abbreviated to I₄₀, I₆₀, I₈₀ and I₁₀₀, respectively) during 2006–2007. Total dry matter production reached a maximum of 24.4 and 23.5 t ha^?1at I₄₀ and I₆₀ at N₂₂₅, respectively. Nitrogen use efficiency decreased by adding more fertilizer and minimum nitrogen use efficiency was recorded at N₂₂₅ over all irrigation regimes. At N₂₂₅, water use efficiency reached the maximum of 3.57 and 4.10 kg m^?3 in I₈₀ and I₁₀₀, respectively. Pearl millet forage could be produced in the regions where water is scarce and additional N fertilizer could increase total dry matter and water use efficiency.     

Performance of Turmeric and Soil Moisture Depletion Pattern Under Different Water Regimes and Nutrient Sources at New Alluvial Zone of Indo-Gangetic Plains,India

In India, the production of turmeric is not even half compared to its potential. To analyze the possibilities for higher production in turmeric, this study was conducted at the BCKV, Gayeshpur, West Bengal, during 2011 and 2012, to evaluate the effect of irrigation scheduling (0.6, 0.9, and 1.2 irrigation water (IW)/cumulative pan evaporation (CPE) and rainfed) in main plots and nutrient management [100% inorganic, 75% inorganic + 25% FYM (Farm yard manure), and 50% inorganic + 25% FYM + 25% vermicompost] in subplots on soil moisture depletion and productivity of turmeric. The highest value of fresh rhizome yield (23.90 kg ha^?1) and qualitative indices were obtained with irrigation schedule at 0.9 IW/CPE ratio water regimes and 50% inorganic + 25% FYM + 25% vermicompost. The correlation coefficients of water use and yield of turmeric were found at 0.943. The combination of 0.9 IW/CPE and 50% inorganic + 25% FYM + 25% vermicompost improved the overall performance of turmeric crop.     

Drought Tolerance and Ion Accumulation of Rice Following Application of Additional Potassium Fertilizer

Five levels of water stress cycle (control flooded, control saturated, 5, 10, and 15 days of irrigation interval) and three potassium fertilization levels [80 kg, 120 kg, and kg 160 dipotassium oxide (K₂O) ha^?1] were exposed to investigate the influence of potassium fertilizer for minimizing water stress effect and maximizing productivity of rice. Different phyto-physiological parameters as well as uptake of major nutrient elements [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe)] were examined. It was observed that rice yield, harvest index, and other physiological parameters reduces with increasing duration of water stress while application of additional potassium fertilizer has progressive impact on those parameters. From our observation, 10 days of watering cycle with potassium fertilization at 120 kg K₂O ha^?1 produces highest grain yield and harvest index. Uptake of major nutrient elements was also enhanced by potassium fertilizer. Therefore, it can be stated that additional potassium fertilizer application could be useful to mitigate water stress effect in rice.     

Modulation in growth,development, and yield of Camelina sativa by nitrogen application under water stress conditions

Camelina sativa has rejuvenated as a successful oilseed crop in the recent years. It is a low-input-requiring crop with an unusual fatty acid composition. A pot experiment was conducted in rain-out shelter to investigate the effect of different nitrogen levels (N₀ = 0, N₁ = 50, N₂ = 100, and N₃ = 150 kg ha^?1) on the growth and yield of two C. sativa genotypes (Australian and Canadian) under normal [100% field capacity (FC)] and water stressed (60% FC) conditions. The experiment was laid out in a completely randomized design with factorial arrangement having three replicates in the Department of Crop Physiology, University of Agriculture, Faisalabad. The results indicated that nitrogen doses and water stress levels significantly affected the growth and yield of C. sativa. Maximum values for growth indices like leaf area index (LAI), crop growth rate (CGR), leaf area duration (LAD), net assimilation rate (NAR), and yield attributes were observed under N₂ treatment (100 kg ha^?1) followed by the treatment in which nitrogen was applied at the rate of 50 kg ha^?1. However, growth and yield components significantly reduced under water stress conditions (60% FC). Of both the genotypes, Australian Camelina performed better as compared to Canadian Camelina under both non-stress and drought stress conditions.     

Yield responses of cauliflower (Brassica oleracea L. var. Botrytis) to different water and nitrogen levels in a Mediterranean coastal area

Abstract

Global warming along with the increasing population and fresh water shortages necessitates a specific fertilization programme under water-scarce conditions. This study was conducted to investigate the effects of different irrigation and nitrogen levels on yield, growth components and water use characteristics of cauliflower (Brassica oleracea L. var. Botrytis cv. Tetris-F1) cultivated in a field for three consecutive years from 2005 to 2007 in the Eastern Mediterranean region of Turkey. Four irrigation (Kcp) levels with a drip irrigation system based on adjustment coefficients (0, 0.75, 1.0 and 1.25) of pan evaporation were used. Nitrogen (N) treatments were consisted of four different nitrogen rates (0, 75, 150 and 225 kg N ha^–1). The following yield and quality parameters were determined: curd weight, curd diameters, number of leaves per crop, above ground biomass (AGB) and curd/AGB ratio. Fertilizer use efficiency (FUE) and leaf mineral contents were also determined to clarify the productivity of N treatments. According to the results; the amount of irrigation water and/or total received water affects the plant water consumption, consequently, crop yield in a field grown cauliflower. The highest yield was obtained in Kcp1.0 irrigation level which represents full irrigation treatment. The excess water applications had negative effect on yield and AGB of cauliflower. Highest yield was obtained at 225 kg N ha^–1.

The water use efficiency and irrigation water use efficiency values increased with decreasing irrigation rate. However, lower Kcp coefficients resulted in lower total yield. The FUE in irrigation treatments showed linear increases from non irrigation to full irrigation plots. However, excessive irrigation caused a decrease in FUE. It can be recommended that the Kcp1.0 crop-pan coefficient with 225 kg ha^–1 nitrogen application can be used to achieve the highest yield for field grown cauliflower in the Eastern Mediterranean coastal region of Turkey.     

Maize root development and grain production as affected by soil and water management on a sandy soil in a semi-arid region of southern Mozambique

Average yield of maize (Zea mays L.) in Mozambique is low, mainly due to low use of inputs in agriculture, high seasonal rainfall variability and inadequate soil preparation. A study conducted in two summer crop seasons (November–March 2012/2013 and 2013/2014) examined the impact of three tillage methods (hand hoeing, strip tillage and conventional tillage), two fertiliser levels (0 and 40% N) and two water supply regimes (rainfed and irrigated) on maize root development and grain yield on a sandy soil in a semi-arid region of Mozambique. Tillage had a major effect on soil penetration resistance, but little effect on root growth and limited effect on yield. Thus, there appears to be little need for loosening on this soil. There was also no interaction between tillage and the other experimental factors, meaning that tillage system can be chosen irrespective of fertiliser and water supply. Irrigation had the largest impact on root and shoot growth and crop yield, increasing yield in season 2 from 670 to 4780?kg ha^–1.There was a very strong interaction between fertiliser and water supply, with no yield increase for fertiliser in the rainfed treatment, while combined with irrigation it increased yield by 1590?kg ha^–1 in season 1 and 1840?kg ha^–1 in season 2. Thus, for the conditions studied here, it was rational to add fertiliser only in combination with irrigation and not in a rainfed system.     

Effects of Zeolite and Zinc on Quality of Canola (Brassica napus L.) Under Late Season Drought Stress

The research was performed to investigate the effect of zeolite and zinc on the qualitative characteristics of canola cultivars at different moisture regimes. Factorial split plot experiment was performed on the basis of the randomized complete blocks design with three replications in Karaj, Iran. The treatments were: 1) irrigation (I): complete (normal irrigation) (I₁), and restricted irrigation (I₂) applied at the pod formation stage, 2) zeolite (Z): 0 (Z₁), and 15 t ha^?1 (Z₂), and 3) Zn: zinc sulfate concentrations of 0%, 0.1%, and 0.2% (Zn_1, Zn_2, and Zn₃) on Opera, Licord, and RGS003 cultivars. The highest rate of all studied traits was obtained by applying Z₂Zn₂ (15 ton ha^?1 zeolite and 0.1% zinc sulfate) in both irrigation regimes. Opera cultivar in normal irrigation and RGS003 cultivar in stress conditions had the highest yield and yield components, oil yield, and oil content.