HSI Values Research Articles

Selection of aquaculture sites by using an ensemble model method: a case study of Ruditapes philippinarums in Moon Lake

Manila clam Ruditapes philippinarum is one of the most important bivalve species, with high commercial value, cultured in coastal areas around the world. However, few studies have attempted to model the suitable habitats of this species. For farming, knowledge of suitable habitat is critical information. Here, we use an ensemble-modelling approach implemented in the biomod2 platform to examine potential suitable habitats in Moon Lake. Initially, nine single-algorithm species distribution models (SDMs) were constructed by combining 96 Manila clam actual presence-and-absence data with oceanographic and sediment data. A weighted ensemble model was then derived from the different individual models. Results showed that the contribution of the six predictor variables differed among modelling techniques, in general, the substrate-related variables contributed the best at predicting habitat suitability. The performance of single-algorithm models ranged from poor to excellent, and the weighted ensemble model performed better than any individual modelling technique according to performance metrics. The use of an ensemble of predictions allowed us to identify potentially suitable areas for clam farming. The predicted suitable, secondary suitable and general suitable habitat for R. philippinarum accounted for 7.69%, 9.03% and 11.80% of the total area of Moon Lake, respectively. And both the average shell length and biomass of Manila clam displayed positive relationships with HSI value. This ensemble-modelling approach could be a useful tool to identify suitable aquaculture sites for Manila clam farming.

Metazoan parasites, condition factor and hepato-somatic index of amphibians from oil-producing communities in Rivers State, Nigeria

Amphibians were collected from six locations in Rivers State, Nigeria, using search and capture techniques, and purchases from local markets. The locations were Okwale and Teka Sogho in Ogoniland, Akabuka in Omoku, Omofo in Ndele, Rumuche in Emohua and Ikata in Ahoada East. Amphibians were euthanized; body mass, liver mass, and snout-vent length of each specimen were taken after which they were examined for helminth endoparasites in the gastrointestinal tract, lungs, liver, urinary bladder and body cavity. Prevalence and mean intensity of parasite infections were computed; body condition factor and hepato somatic index of amphibians were also computed. Amphibian species encountered included Sclerophrys spp., Hoplobatrachus occipitalis, Silurana tropicalis, Hymenochirus sp., and Ptychadena species. Parasite species recovered were trematodes (Prosotocus exovitellosus, Ganeo africana, Diplodiscus fischthalicus, Metahaematoloechus exoterorchis, Mesocoelium monodi, Mesocoelium sp.), cestodes (Baerietta jaegerskioeldii), acanthocephalan cysthacanths, pentastomids (Raillietiella sp.), monogeneans (Polystoma aeschlimanni, P. baeri and P. pricei), and nematodes (Amplicaecum africanum, Ascaridida larva, Batracocamallanus siluranae, Chabaudus leberrei, Cosmocerca ornata, Oswaldocruzia hoepplii, Rhabdias africanus, Rhabdias sp. 1 and 2. Hymenochirus sp. is reported as a new host for C. leberrei. Parasite community structure closely followed that of the hosts. Parasites were generally less prevalent in hosts from Ogoni and Omoku. Condition factor of all amphibians examined were greater than 1. Higher HSI values were recorded in Hymenochirus sp. from Akabuka Omoku indicating higher stress level in that location.Keywords: Helminth; health status; petroleum industry; anthropogenic change; habitat alteration.

Effects of the Feeds Containing Hazelnut Meal as Plant Protein Source on Growth Performance and Body Composition of Siberian sturgeon (<i>Acipenser</i> <i>baeri</i>) and Economic Profitability Value

In this study, the effects of feeding with the diets containing hazelnut meal (HM) at different levels (0%, 15%, 30%, and 45%) on the growth performance and body composition of Siberian sturgeon were investigated. The study was carried out for 90 days with 3 replicates (n = 15; 283.1 ± 6.52 g fish weight). The highest weight gain (180.62 ± 2.84%) was observed in the control group followed by 15%, 30%, and 45% HM. When the groups were evaluated in terms of SGR, FCR, and PER, the control group was observed to have the best performance. The control group and the 15% HM group, which were statistically similar, were found to be different from the other groups (P < 0.05). The statistical difference between the control group and the 45% HM group of HSI values was significant (P < 0.05). CP, CF, and GE values were found to be similar in the control group and 15% HM groups and different from other groups (P < 0.05). Finally, it was concluded that adding 15% HM to the diet would positively affect fish growth in terms of growth performance, ECR, meat quality, and body composition, but considering the economic performance, it is determined that the rate of HM can be increased up to 45%.

Some Observations on Relationships of the Liver, Ovary and Body Weights for Pipefish Species at the Lake Bafa Coasts (Muğla)

This study aims to determine various relationships between liver, gonad and body weights of the two pipefish species caught in two breeding seasons from the Bafa Lake (Muğla) coasts between 2014 -2016. Using beach seine-net in the lake, a total of 208 pipefish specimens (79 Synathus abaster and 129 Synathus acus) were sampled. L-W relationship and Fulton condition factor were W = 2E - 0.94.01, 0.035 ± 0.009 in S.abaster specimens. Also LW relationships and condition factor were W = 8E-0.93.83 , 0.033 ± 0.01 in S. acus. On the other hand mean ± SD of HSI and GSI values were 2.18 ± 1.65 and 7.69 ± 7.12 respectively. In S.acus values 3.22 ± 3.13 and 5.49 ± 5.12 as well. The decrease in HIS and K values, provides sufficient information to claim that species in the lake spend all energy requirement obtained with proper feeding to growth and gonad development.

Seasonal habitat patterns of jumbo flying squid Dosidicus gigas off Peruvian waters

Abstract Habitat modeling approach is a useful tool to detect potential habitat of pelagic fish species for better fishery exploitation and management. In this study, an integrated habitat modeling approach was applied to examine seasonal habitat patterns of an ecologically and economically important squid species Dosidicus gigas in the Southeast Pacific Ocean off Peruvian waters. Fisheries data of D. gigas and three crucial remotely-sensed environmental variables including sea surface temperature (SST), net primary production (NPP) and sea surface height anomaly (SSHA) during 2006–2015 were used to develop and validate the habitat model. Results revealed that the model output robust predictions of seasonal habitat suitability for D. gigas stock. Potential habitat exhibited strong seasonal variability, characterized by an expansion of suitable habitat during spring-autumn period and an extreme reduction in winter. These seasonal habitat patterns of D. gigas were largely driven by spatial distribution of favorable environmental conditions. Spatial correlation analysis indicated that the habitat quality of D. gigas was negatively correlated with SST in the areas between 8°–15°S and 87°–79°W and with SSHA on the whole fishing ground. However, a negative relationship was found between HSI values and NPP in the east of 84°W, but with a significantly positive correlation in the west of 84°W. In addition, seasonal variations of CPUEs and latitude distribution of fishing efforts were highly coincided with the variability trends in the area of suitable habitats and their latitudinal distributions. Interannual variability was shown in the averaged HSI of D. gigas. Furthermore, comparing to the strong El Nino year in 2015, the La Nina event in 2011 yielded more enlarged favorable regions of each environmental factor in each season, leading to form extremely high-quality habitats.

Length-Weight Relationships, Reproduction, Hepatosomatic Index of The Lesser Spotted Catshark, Scyliorhinus canicula [L.] The Sea of Marmara, Turkey

Some biological aspects of 91 lesser spotted catshark Scyliorhinus canicula [L.] were examined. The samples were caught with trawl hauls from Bandırma Bay in the years of 2013-2014. Total lenghts of fishes ranged from 18.0-47.4 cm while their weights ranged from 28.78-583.78 g. It was observed that lenght-weight increased allometrically. As the overall sex ratio [male and female ] was 1.12:1, it was not found statistically significant [p&amp;gt;0.05]. The mature females were determined to spawn successively at least two eggs each batch. HSI values were estimated not to have significant differences between males and females [P&amp;gt;0.05].

Utilization of cinnamon Cinnamomum burmannii leaves and shrimp head in the feed on growth performance of catfish Pangasianodon hypopthalmus

&lt;p align="center"&gt;&lt;strong&gt;ABSTRACT&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Catfish farming has confronted with the problem of slow growth to reach the fillet size and less tender of fish fillets. This study aimed to investigate the effect of cinnamon leaf flour and shrimp head flour in formulated diets on growth of catfish &lt;em&gt;Pangasi&lt;/em&gt;&lt;em&gt;anodon&lt;/em&gt;&lt;em&gt; hypopthalamus&lt;/em&gt;. Catfish with an initial weight of 207.04 ± 2.70 g/fish reared in 12 cages with a dimension of 2×1×1.5 m&lt;sup&gt;3&lt;/sup&gt; (L×W×H) and its fish density was 15 fishes for 60 days. Fish were fed with following experimental diets: (1) Control; (2) cinnamon leaf (1%) (CL); (3) 45% of protein source from shrimp head (SH); (4) CL+SH mix. The fishes fed twice a day with feeding rate 3.5% of fish biomass. The study found that the use of cinnamon leaf and shrimp head increased the specific growth rate 1.67-1.70%, the feed efficiency 57.55-57.67%, and protein retention 55.61% compared to its control (P&amp;lt;0.05). Triglyceride level, cholesterol, and blood HDL were 416.00-524.05 mg/dL, 139.65-156.68 mg/dL, 73.18-103.70 mg/dL (P&amp;gt;0.05), respectively. HSI value ranged between 0.3-1.9% compared to its control (P&amp;lt;0.05).&lt;/p&gt;&lt;p&gt;Keywords: &lt;em&gt;Cinnamomum burmannii&lt;/em&gt;, feed, growth, &lt;em&gt;Pangasianodon hypopthalmus&lt;/em&gt;&lt;em&gt;, &lt;/em&gt;shrimp head.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p align="center"&gt;&lt;strong&gt;ABSTRAK&lt;/strong&gt;&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Budidaya ikan patin dihadapkan pada permasalahan pertumbuhan dan kualitas daging yaitu pertumbuhan yang lambat untuk mencapai ukuran &lt;em&gt;fillet&lt;/em&gt; serta tekstur daging kurang kompak. Tujuan penelitian ini adalah untuk menguji pengaruh penggunaan tepung daun kayu manis dan tepung kepala udang dalam pakan terhadap pertumbuhan ikan patin &lt;em&gt;Pangasi&lt;/em&gt;&lt;em&gt;anodon&lt;/em&gt;&lt;em&gt; hypopthalmus&lt;/em&gt;. Ikan patin dengan bobot 207,04 ± 2,70 g/ekordipelihara selama 60 hari di hapa sebanyak 12 buah (berukuran 2×1×1,5 m&lt;sup&gt;3&lt;/sup&gt;)dengan padat tebar 15 ekor/jaring. Ikan diberi pakan perlakuan yang terdiri dari: (1) Kontrol; (2) daun kayu manis 1% (DKM); (3) 45% sumber protein dari kepala udang (TKU); dan (4) campuran DKM+TKU. Pemberian pakan sebanyak 2 kali sehari dengan &lt;em&gt;feeding rate&lt;/em&gt; 3,5% dari biomassa ikan. Hasil dari penelitian penggunaan daun kayu manis dan kepala udang meningkatkan nilai laju pertumbuhan harian 1,67-1,70%, efisiensi pakan 57,55-57,67% dan retensi protein 55,61% dibanding kontrol (P&amp;lt;0,05). Kadar trigliserida, kolesterol, dan HDL darah berturut-turut adalah 416,00-524,05 mg/dL, 139,65-156,68 mg/dL, 73,18-103,70 mg/dL (P&amp;gt;0,05). Nilai HSI ikan patin berkisar antara 0,3-1,9% dibanding kontrol (P&amp;lt;0,05).&lt;/p&gt;&lt;p&gt;Kata kunci: &lt;em&gt;Cinnamomum burmannii, &lt;/em&gt;kepala udang, pakan, &lt;em&gt;Pangasianodon hypopthalmus&lt;/em&gt;, pertumbuhan.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;

EFFECT OF PHOTOPERIOD ON GROWTH PERFORMANCE, FEED UTILIZATION AND CARCASS COMPOSITION IN CHANNA PUNCTATUS

To study the effect of photoperiod on growth performance in C. punctatus, the fish were exposed to three combinations of day length i.e. LD 14:10, LD 12:12 and LD 9:15 at 25°C. Variables tested were weight gain, length gain, condition factor, FCR, body composition, VSI and HSI. Fish exposed to long photoperiod showed high growth performance followed by equal and short photoperiod. Significantly low concentration of ammonical nitrogen and orthophosphate in holding water were observed in fish exposed to LD 14:10 as compared to LD 12:12 and LD 9:15. VSI values were significantly high (P0.05) in group of fish exposed to LD 14:10, followed by LD 12:12 and LD 9:15. On the other hand, HSI was significantly decreased in fish exposed to LD 9:15, while HSI values under LD 14:10 and LD 12:12 were equal.

Determination of Condition Factor (CF) and Hepatosomatic Index (HSI) of Barbonymus schwanenfeldii from Galas River, Kelantan

The rapid growth of agriculture and industrial activities has resulted in decreasing of water quality in the aquatic ecosystem, which is significantly hazardous for fish health. Fish are commonly situated at the top of aquatic food chain is known to be nutritious with essential proteins. The purpose of this study is to determine the condition factor and hepatosomatic index of Barbonymus schwanenfeldii from Galas River, Kelantan. The sizes of slaughtered fish ranging from 319 ± 0.05 to 456 ± 1.32 g in weight while 28 ± 0.34 to 36 ± 1.42 cm in total length. From a sample size of 40 specimens, the average of K value was 1.15 ± 0.21 and 2.31 ± 0.13 of HSI value. Thus, the results revealed that the fish species was in a poor condition. Refer to the matter; the condition of study area is not suitable for fish habitat. Condition factor of fishes is important biological parameter which can provides information on fish well-being. The condition factor and hepatosomatic index compares the well-being of a fish is based on the hypothesis that heavier fish of a given length are in a better condition.

Determination of Condition Factor (CF) and Hepatosomatic Index (HSI) of Barbonymus schwanenfeldii from Galas River, Kelantan

The rapid growth of agriculture and industrial activities has resulted in decreasing of water qualityin the aquatic ecosystem, which is significantly hazardous for fish health. Fish are commonlysituated at the top of aquatic food chain is known to be nutritious with essential proteins. Thepurpose of this study is to determine the condition factor and hepatosomatic index of Barbonymusschwanenfeldii from Galas River, Kelantan. The sizes of slaughtered fish ranging from 319 ± 0.05to 456 ± 1.32 g in weight while 28 ± 0.34 to 36 ± 1.42 cm in total length. From a sample size of 40specimens, the average of K value was 1.15 ± 0.21 and 2.31 ± 0.13 of HSI value. Thus, the resultsrevealed that the fish species was in a poor condition. Refer to the matter; the condition of studyarea is not suitable for fish habitat. Condition factor of fishes is important biological parameterwhich can provides information on fish well-being. The condition factor and hepatosomatic indexcompares the well-being of a fish is based on the hypothesis that heavier fish of a given length arein a better condition.

OPTIMALISASI LAMA PEMAPARAN LASERPUNKTUR PADA TITIK REPRODUKSI TERHADAP PENINGKATAN NILAI HEPATO SOMATIC INDEX (HSI) DAN GONADO SOMATIC INDEX (GSI) IKAN GABUS (Channa striata)

Snakefish fishing continuously can reduce the number of mature stem gonad great sizenya increasingly few in number in nature will certainly affect the reduction in seed production in the waters and may even become extinct. Efforts should be made restoking with laserpuncture technology. Laserpuncture technology has been shown to accelerate the maturation of the gonads in tilapia, catfish, shrimp, crab, but has never been tried on the snakefish brood (Channa striata). The purpose of this study to obtain optimum exposure time laserpuncture at the acupoint of reproduction to increase the value of HSI and GSI snakefish (Channa striata) male parent in order to get ready for spawning. Research experiments using CRD with 5 treatments and repeated 3 times. To get the value of HSI and GSI by weighing the weight, liver weight and gonadnya. The sample used in this study snakefish brood 1 year old male with a weight range from 1100-1400 grams have never spawn. HSI and GSI value analysis using ANOVA Gen Stat program version 15. The results showed exposure at the acupoint of reproduction laserpuncture significant effect (P &lt;0.05) increase in the value of HSI and GSI. Laserpuncture exposure time at the acupoint of reproduction for 4 seconds proved to be optimal to increase the value of HSI and GSI parent catfish than in controls.&#x0D; &#x0D; Keywords: Laserpuncture, the value of HSI and GSI snakefish

Two-phase anticipatory system design based on extended species abundance model of biogeography for intelligent battlefield preparation

This paper presents an extended model of biogeography based optimization (BBO) as opposed to the classical BBO wherein the HSI value of a habitat is not solely dependent upon the emigration and immigration rates of species but the HSI value is a function of different combinations of SIVs depending upon the characteristics of the habitat under consideration. The extended model also introduces a new concept of efforts required in migration from a low HSI solution to a high HSI solution for optimization in BBO. Hence, the proposed extended model of BBO presents an advanced optimization technique that was originally proposed by Dan Simon as BBO in December, 2008. Based on the concepts introduced in our extended model of BBO and its mathematics, we design a two – phase anticipatory system architecture for intelligent preparation of the battlefield which is the targeted optimization problem in our case. The proposed anticipatory system serves a dual purpose by predicting the deployment strategies of enemy troops in the battlefield and also finding the shortest and the best feasible path for attack on the enemy base station. Hence, the proposed anticipatory system can be used to improve the traditional approaches, since they lack the ability to predict the destination and can only find a suitable path to the given destination, leading to coordination problems and target misidentification which can lead to severe casualties. The designed system can be of major use for the commanders in the battlefield who have been using traditional decision making techniques of limited accuracy for predicting the destination. Using the above natural computation technique can help in enabling the commanders in the battlefield for intelligent preparation of the battlefield by automating the process of assessing the likely base stations of the enemy and the ways in which these can be attacked, given the environment and the terrain considerations. The results on two natural terrain scenarios that of plain/desert region of Alwar and hilly region of Mussourie are taken to demonstrate the performance of the technique where the proposed technique clearly outperforms the traditional methods and the other EAs like ACO, PSO, SGA, SOFM, FI, GA, etc. that have been used till date for path planning applications on satellite images with the smallest pixel count of 351 and 310 respectively. For location prediction application, the highest prediction efficiencies of the traditional method on Alwar and Mussourie was only 13% and 8% respectively as compared to the proposed method.

Morphological and liver histological effects of ZnO nanoparticles on Mozambique Tilapia

Three different concentrations (30, 50 and 70ppm) of ZnO NPs were exposed to Oreochromis mossambicus. Treated fishes showed various skin discolouration and ulceration due to necrosis condition of muscle tissues, damages in Pectoral, Caudal and Dorsal fins than control. HSI values of treated groups showed decreasing HSI results for 30ppm, 50pp, and 70ppm groups as increasing concentrations. Liver Histological results showed congested portal vein (CPV), necrotic hepatocytes and vacuole formation, accumulation of blood cells degradation of liver tissues (DL) in treated fishes. As a novel attempt this study reveals the impact of ZnO NPs on morphology of O.mossambicus.

An analysis of the habitat of the Greater One-horned Rhinoceros Rhinoceros unicornis (Mammalia: Perissodactyla: Rhinocerotidae) at the Chitwan National Park, Nepal

We used Geographic Information Systems (GIS) and landscape-level data obtained from remote sensing sources to build a habitat suitability index model (HSI) for the Greater One-horned Rhinoceros Rhinoceros unicornis. The model was based primarily on important habitat requisites of the modeled species, especially food and cover. We extracted food and cover from land cover map and ran focal statistics to determine their proportion in a neighborhood of 70x70 pixels that accounts for the animal’s average mean annual home range, which is ~4km2 = 400 ha = 70x70 pixels x 900 m2 = 4410000/10000 = 441 ha. We used two arbitrarily selected parameters a and Tc to observe the impacts of food and cover on the HSI. We performed sensitivity analysis by varying values of parameters around their nominal, which revealed that the HSI value of a pixel is changed with uncertainty with very low values of a fraction of the food or cover. We identified four habitat types from the HSI map. We used patch and class metrics of FRAGSTATS program to estimate the amount and fragmentation of each habitat type. The metrics provided composition and configuration status for all four habitat types. We found a presence of a total of 476 patches with 517.82km2 belonging to suitable habitat type. These areas can be targeted for management, monitoring and improvement to provide habitat for the target and sympatric species.

Production, maturity, reproductive cycle and fecundity of small-spotted catshark, Scyliorhinus canicula (Chondrichthyes: Scyliorhinidae) from the northern coast of Tunisia (Central Mediterranean)

Small-spotted catshark Scyliorhinus canicula (Linnaeus, 1758) is confronted since 2000 to a drastic decline of captures in Tunisian northern areas where it formerly was quantitatively and qualitatively very abundant. A study conducted in the area showed that males and females sexually matured between 400–478 mm and 364–471 mm total length (TL), respectively. The largest male and female were 521 mm and 531 mm TL, respectively and weighed 449 and 445.5 g, respectively. There was a not significant relationship total mass vs. TL between males and females. Conversely, the relationship of liver mass vs. TL significantly differed between sexes. Both HSI and GSI values did not present significant differences between males and females. There was a not significant relationship total mass vs. TL between males and females. Both male and female HSI reached high values in adults, significantly higher than those of sub-adults. Both male and female GSI values increased with TL of specimens; additionally, they showed significant differences between juveniles and sub-adults and also between sub-adults and adults. The OSI values were significantly different between juvenile and sub-adult females, and also between sub-adult and adult females. Monthly mean values of adult male and female HSI did not significantly vary throughout the year. Significant monthly changes were recorded in mean values of adult male however no significant changes were observed in monthly mean of GSI and OSI for adult females. Vitellogenic activity and production of egg cases permanently occurred throughout the year. The diameter of largest yolky oocytes ranged from 20.1 to 23.0 (mean = 21.43 ± 1.07) and weighed from 0.64 to 0.90 g (mean = 0.78 ± 0.09). Some measurements were taken on egg cases: length with horns ranged 42.5-55.7 mm with mean = 48.9 ± 2.9, width ranged 13.6–19.7 mm with mean = 16.50 ± 0.9, while the total mass of complete egg case ranged between 1.8 and 4.6 g, with mean = 2.4 ± 0.4. An annual fecundity estimation based on production of egg cases and oocytes during one year counted in adult females, enabled us to consider it between 40 and 240.

참외 수확로봇을 위한 타원 정합기반의 인식 기법 개발

In this paper, vision-based positioning algorithm for melon harvesting robot is presented. RGB value of the input image was converted into HSI value then, melon area was extracted after performing the binarization using HUE value. After morphological filtering was applied to remove noise, outermost boundary points were obtained using border following and convex hull method. Elliptical fitting for melons was perform by the RANSAC algorithm, the center point of ellipse, the length of the short and long axis, and rotation angle were obtained. We verified the effectiveness of the proposed method by various simulation experiments and confirmed actual feasibility of the proposed method by applying to the real melon.

Alterations in Morphometric and Organosomatic Indices and Histopathological Analyses Indicative of Environmental Contamination in Mullet, Mugil liza, from Southeastern Brazil

Mullet (Mugil liza) were sampled in five different areas along the Guanabara Bay, southeastern Brazil, classified as non-contaminated, moderately contaminated and contaminated. Morphometric (Fulton condition factor, relative condition factor and weight to length scaling coefficient) and organosomatic (hepatosomatic index) indices of environmental stress were analysed. Fish from the differentially contaminated areas show statistically different Fulton and relative condition factors and hepatosomatic indices, but not the weight to length scaling coefficient. The Kn and the FCF followed the same trend, with fish from São Gonçalo (1.07 ± 0.04 and 0.89 ± 0.03), Itaipu (0.84 ± 0.01 and 0.86 ± 0.01) and the Rodrigo de Freitas Lagoon (1.03 ± 0.01 and 0.87 ± 0.20) showing higher FCFs than fish from Magé (0.96 ± 0.01 and 0.81 ± 0.01). Fish from Itaipu showed significantly higher HSI values than the other sampling sites (1.68 ± 0.07), with fish from Olaria and Ipiranga showing the lowest (1.56 ± 0.12 and 1.60 ± 0.07, respectively).

Stability analysis of selected wheat genotypes under different environment conditions in upper Egypt

The experiment was conducted during winter 2010 and 2011 to assess heat tolerance of 17 genotypes under four environments (two sowing dates with two years). The combined analysis of variance showed that the differences between genotypes as well as GXE were highly significant for grain yield, 1000 grain weight, number of kernel/spike and spike length. The genotypes No. 1, 2, 3 and 7 gave high mean grain yield, regression coefficient b not significantly from unit and considered more stable. Meanwhile, genotypes No. 1, 2, 4, 15 and Giza-168 showed below average stability (b=1.92, 1.72, 2.24 and 1.6). Also, genotypes No. 1, 2, 3 and 7 were relatively heat resistance (HSI values <1), while local variety Giza-168, Sids-12 genotypes No. 13, 14 and 12 were relatively susceptible to heat stress. In general, in drought environments, grain yield of genotypes No. 1, 2 and 3 were the highest. Key words: Environment, genotype, genotype by environment interaction, grain yield, heat stress.

Performance of Yield and Stability of Wheat Genotypes under High Stress Environments of the Central Region of Saudi Arabia

The current study aimed at assessing the heat tolerance of twelve wheat genotypes under four environmental conditions (two sowing dates and two years). Wheat genotypes were sown at two dates: December (favorable) and January (heat stress) during winter seasons of 2005/2006 and 2006/2007. The combined analysis of variance showed that plant height, spike length, number of kernels per spike, harvest index and grain yield were significantly influenced by years, sowing dates, and genotypes. The results showed that sowing at the first date increased plant height, grain yield, and harvest index. Highly significant genotype differences were recorded for all characters. In general, genotypes (YR-19 and YR-20) produced the highest grain yield in both seasons, while, local cultivar 'Sama' produced the lowest grain yield. Regarding the interaction effect between sowing dates and wheat genotypes on grain yield, YR-20 produced the highest grain yield under the first sowing date. The stability analysis revealed that genotypes YR- 19 and YR-20 showed high and stable yielding. On the other hand, YR- 2 and YR-3 showed below-average stability (b = 1.582 & 1.594). Also, the genotypes YR-20 and YR-19 were relatively heat resistant (HSI values 1).

The effect of varying dietary energy on gonad development at first sexual maturity of the Sharptooth catfish (Clarias gariepinus Burchell, 1822)

The objective of this study was to investigate the effects of five isonitrogenous (35% crude protein) diets having different energy contents; 10.85, 11.82, 12.73, 13.69, and 15.06 MJ DE/kg, respectively, on the gonad development and weight gain of Sharptooth catfish fingerlings. Energy contents of the experimental diets were increased with the increasing amount of soy-acid oil (0, 4, 8.5, 13, 18%) and each group of fish was fed on their respective diets (group I was fed diet I) during 180 days. The gonad maturation was significantly affected by dietary energy. In both sexes, the histological inspections of the gonads did reveal differences among the fish fed different energetic diets. Fish fed diets I, II, and III had significantly heavier and more developed gonads compared to those on diets IV and V. Fish fed the higher energetic diets (IV and V) had partially low numbers of yolky oocytes compared to other groups. The mean GSI values of female and male fish fed with diet III was significantly greater than those fed diets with higher dietary energy; however, higher HSI values were recorded for fish fed with the higher energetic diets (IV and V). Also, the best weight gain for both males and females were recorded from the fish fed diet III (12.73 MJ DE/kg). Therefore, on the basis of the present results, among energy levels tested, 12.73 MJ DE/kg was found to be optimal for healthy gonad development and weight gain.