Growth analysis of rhizomania infected and healthy sugar beet     

Javad Rezaei  Mohammad Bannayan  Ahmad Nezami  Mohsen Mehrvar  Bagher Mahmoodi 《Journal of Crop Science and Biotechnology》2014,17(2):59-69

Viral disease of rhizomania is one of the most important diseases of sugar beet all over the world. The disease significantly has reduced the yield and quality of sugar beet, and has imposed high economic loss to farmers. Long-term breeding programs to introduce tolerant cultivars are the only chance of avoiding further yield losses. This study tried to measure and analyze the growth of shoots and roots of rhizomania-tolerant and -susceptible sugar beet with the aim of providing information for modeling of the rhizomania effects on the growth of sugar beet. Growth indices were used for analyzing, quantification, and time-course of sugar beet growth under infested and non-infested soils conditions. A 2-year experiment was conducted using four sugar beet cultivars in 2010 and 2011 in Mashhad, Iran. The results of this study showed that under infested soils, root dry matter and leaf area index of the susceptible cultivars in comparison to tolerant cultivars were lower by 57 and 24%, respectively. In addition, crop growth rate and net assimilation rate of susceptible cultivars were affected by rhizomania and were lower than in tolerant cultivars. On non-infested soil, the difference between dry matter and growth indices of susceptible and tolerant sugar beet cultivars was not significant. Rhizomania decreased green area and photosynthesis capacity and led to lower growth rate and dry matter production. Our study quantified the growth of rhizomania-infested sugar beet plants in comparison with non-infested plants and provided information to be used for modeling of the rhizomania effects on the growth of sugar beet.  相似文献   

Impacts of decentralized fish fingerling production in irrigated rice fields in Northwest Bangladesh     

Mohammad Mahfujul Haque  David C Little  Benoy K Barman  Md Abdul Wahab  Trevor C Telfer 《Aquaculture Research》2014,45(4):655-674

Rice field‐based fish seed production (RFFSP) has become established in parts of Northwest Bangladesh (NWB) as part of promoting improved rice‐based livelihoods. The impact of RFFSP on adopting households in terms of interactions of assets and other activities was assessed in a comparison of seed‐producing (RF; n = 60) and non‐seed‐producing (NRF; n = 58) households that were sampled randomly and ranked as poor, intermediate and better‐off. Adoption of RFFSP was not constrained by illiteracy of the household head, the size or ownership status of ponds, or lack of ownership of land or an irrigation pump. Poorer and intermediate households had smaller RF plots and lower production of fingerlings (kg per household) compared with the better‐off, although production efficiency (kg ha^?1) was higher. Restocking of fingerlings in RF household ponds increased productivity by 60% over NRF. Fish consumption of better‐off RF households exceeded NFR by 50%. Among the poor, seasonal benefits of income from sales and subsistence consumption of fingerlings were significant. Rice production in irrigated, and income in both irrigated and rain‐fed seasons was higher, and production costs lower, in riceplots producing fish than in rice‐only plots. Implications for supporting the innovation networks promoting and establishing RFFSP among rice growers, are discussed.  相似文献   

Preliminary observations on growth and survival of Oreochromis spilurus x GIFT Oreochromis niloticus F1 reciprocal hybrids in fresh and seawater     

Mohammad T Ridha 《Aquaculture Research》2014,45(3):528-536

Tilapia has a significant potential for culture in saline environments. There is an increasing demand among tilapia producers to develop a tilapia hybrid that can survive well in marine water conditions. This study compared mean weight (MWT), daily growth rate (DGR), specific growth rate (SGR), survival, feed conversion ratio (FCR), condition factor (K), production rate (PR) and rate of skin lesions, and tail and fin rot as well as eye cataract in the Genetically Improved Farmed Tilapia strain (GIFT) of the Nile tilapia, Oreochromis niloticus (NN) and the salt‐tolerant Oreochromis spilurus (SS), and their F₁ reciprocal hybrids; O. niloticus ♀ x O. spilurus ♂ (NS) and O. spilurus ♀ x GIFT O. niloticus ♂ (SN) in freshwater (0 g L^?1) and seawater (40 g L^?1). Fish (3.5 g) were stocked at 150‐fish m^?3 and fed with sea bream pellets (47% protein) for 180 days. Results showed that in seawater, the SN hybrid had the highest values for MWT (165.9 g), DGR (0.9 g fish^?1 day^?1), SGR (2.14% day^?1), survival (96.3%), PR (23.9 kg m^?3) and best FCR (1.53) followed by the NS hybrid and the NN parent. Both hybrids had significantly lower rates of skin lesions and fin and tail rot than the NN genotype. In freshwater, the NN had the highest values for MWT (255.1 g), DGR (1.40 g fish^?1 day^?1), SGR (2.38% day^?1), K (2.13%) and PR (34.9 kg m^?3) followed by the NS and SN hybrids. High estimate of heterosis for MWT (41.3%), DGR (42.5%), SGR (10.7%) and survival (22.1%) was obtained in the hybrids reared in seawater, indicating that a hybrid vigor was produced and the fast growth trait from the GIFT parent was successfully combined with the salinity tolerance trait from the O. spilurus parent. The better growth performance and survival of the SN hybrid in seawater indicate that this hybrid is more suitable for culture in seawater than its reciprocal hybrid.  相似文献   

Diversity of endophytes across the soil-plant continuum for Atriplex spp. in arid environments     

Mohammad E TAHTAMOUNI  Sa&rsquo  eb KHRESAT  Mary LUCERO  Jesus SIGALA  Adrian UNC 《干旱区科学》2016,8(2):241-253

Endophytes are hypothesized to be transferred across the soil-plant continuum, suggesting both the transfers of endophytes from environment to plant and from plant to soil. To verify this hypothesis and to assess the role of locality, we evaluated the similarity of microbial communities commonly found both in soils and endophytic communities in three arid regions, i.e. the Jornada LTER(Long Term Ecological Research) site in New Mexico, USA, and the research station of Jordan University of Science and Technology(JUST) and Khanasri research station in Badia region of Jordan. Rhizosphere and non-rhizosphere soils, leaves and seeds of Atriplex spp. were sampled. Diversity and distribution of bacteria and fungi across the soil-plant continuums were assessed by tag-encoded FLX amplicon pyrosequencing and sequence alignment. Of the total bacterial OTUs(operational taxonomic units), 0.17% in Khanasri research station, 0.16% in research station of JUST, and 0.42% in Jornada LTER site were commonly found across all the plant and soil compartments. The same was true for fungi in two regions, i.e. 1.56% in research station of JUST and 0.86% in Jornada LTER site. However, in Khanasri research station, 12.08% of total fungi OTUs were found in at least one soil compartment and one plant compartment. Putative Arthrobacter, Sporosarcina, Cladosporium and members of Proteobacteria and Actinobacteria were found across all the soil-plant continuums. Ascomycota, mainly including Didymellaceae, Pleosporaceae and Davidiellaceae were present across all the soil-plant continuums. Microbial communities in two regions of Jordan were similar to each other, but both of them were different from the Jornada LTER site of USA. SIMPER(similarity percentage) analysis of bacterial and fungal taxa for both soil and endophyte communities revealed that dissimilarities of two bacterial genera(Arthrobacter and Sporosarcina) and two fungal genera(Cladosporium and Alternaria) are very high, so they play key roles in the soil-plant continuums. A weighed Pearson correlation analysis for the specific bacterial OTUs in the soil-plant continuums only showed high similarity between the two regions of Jordan. However, fungal groups showed higher similarities among all regions. This research supports the hypothesis of continuity of certain bacterial and fungal communities across the soil-plant continuums, and also explores the influences of plant species and geographic specificity on diversity and distribution of bacteria and fungi.  相似文献   

Growth performance,intestinal histology,and biochemical parameters of rainbow trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>) in response to dietary inclusion of heat-killed <Emphasis Type="Italic">Gordonia bronchialis</Emphasis>     

Sadigheh Shabanzadeh  Maryam Shapoori  Najmeh Sheikhzadeh  Katayoon Nofouzi  Ali Khani Oushani  Mohammad Hamed Najafi Enferadi  Karim Mardani  Amir Ali Shahbazfar 《Fish physiology and biochemistry》2016,42(1):65-71

  相似文献   

Habitats across the life cycle of hilsa shad (Tenualosa ilisha) in aquatic ecosystem of Bangladesh          下载免费PDF全文

M. S. Hossain  S. M. Sharifuzzaman  S. R. Chowdhury  S. Sarker 《Fisheries Management and Ecology》2016,23(6):450-462

Aquatic habitat connectivity is vital for the continued existence of migratory fish. Using GIS and outranking multicriteria analysis based on hydrometeorological data, this study describes habitat preference of egg, fry, juvenile and adult phases of hilsa shad, Tenualosa ilisha (Hamilton), as well as their spawning areas in the aquatic ecosystems of Bangladesh. The total area studied was 29 484 km², about 29% of which belonged to the Meghna, Shahbajpur, Tetulia and Ander Manik rivers, and the channels of Sandwip, Kutubdia and Moheshkhali islands, which provide the most suitable habitat for the species. An additional 27% of moderately suitable area was located in other deltaic rivers and inshore waters. The remaining 44% was offshore deeper water, which was least suitable for hilsa. The most suitable area for spawning, eggs, fry, adults and juveniles was 6, 11, 29, 38 and 56% of the area, respectively. The model outputs were validated against field measurements and fishers’ indigenous knowledge with an accuracy level of 92%. Thus, this study provides key information about the location of hilsa at different stages of its life cycle, information useful in understanding its occurrence over a relatively large geographical area. Information of this kind is useful in fishery conservation and management.  相似文献   

Genetic diversity status of Pacific white shrimp (<Emphasis Type="Italic">Litopenaeus vannamei</Emphasis>) using SSR markers in Iran     

Saiwan Rezaee  Hamid Farahmand  Mohammad Ali Nematollahi 《Aquaculture International》2016,24(2):479-489

Genetic diversity is vital for the maintenance of genetic pool in cultured shrimps. In order to estimate the current status of genetic diversity in Litopenaeus vannamei shrimp in Iran, as an exotic species, a total of 45 individuals from Amiri and Gorgeaj farms in Jask port of Hormozgan province and one hatchery in Gomishan city of Golestan province, were detected using four microsatellite loci. The number of alleles per locus was 5–10, and the mean effective number of alleles (N _e) across populations and loci ranged from 4.834 to 5.148. The overall mean observed heterozygosity (H _o) ranged from 0.450 to 0.479, which was lower than the expected one (0.789–0.794). There was nothing remarkable about any of the allele frequencies across populations or loci. The mean inbreeding coefficient (F _IS) and pairwise genetic differentiation (F _ST) among populations were 41.6 % and 0.133, respectively. The three studied populations departed from Hardy–Weinberg equilibrium (HWE). Analysis of molecular variance revealed 14 % variability among and 86 % within populations. However, considering departing from HWE and the high F _IS and F, the moderate pairwise F _ST values, importance of introducing genetically diverse broodstock and monitoring to control inbreeding is discussed.  相似文献   

Co‐infection of Nucleospora cyclopteri (Microsporidia) and Kudoa islandica (Myxozoa) in farmed lumpfish,Cyclopterus lumpus L., in Norway: a case report          下载免费PDF全文

M Alarcn  E Thoen  T T Poppe  G Born  S N Mohammad  H Hansen 《Journal of fish diseases》2016,39(4):411-418

  相似文献   

Integrating parametric and non-parametric measures to investigate genotype × environment interactions in tall fescue     

Mohammad Reza Dehghani  Mohammad Mahdi Majidi  Aghafakhr Mirlohi  Ghodratollah Saeidi 《Euphytica》2016,208(3):583-596

  相似文献   

Selection for productivity,persistence and drought tolerance in orchardgrass     

Fatemeh Saeidnia  Mohammad Mahdi Majidi  Aghafakhr Mirlohi  Samane Shahidaval 《Euphytica》2016,212(1):111-130

  相似文献