bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genotype and phenotype associations with drought tolerance in barley tested in North Africa
Authors: FORSTER B P , ELLIS R P , MOIR J , TALAMÈ V , SANGUINETI M C , TUBEROSA R , THIS D , TEULAT‐MERAH B , AHMED I , MARIY S A E E , BAHRI H , EL OUAHABI M , ZOUMAROU‐WALLIS N , EL‐FELLAH M , BEN SALEM M 
Published: July 2006

SummaryA review is presented of genetic strategies deployed in a 3‐yr project on drought tolerance in barley. Data were collected on genetic, physiological and agronomic traits in non‐irrigated and irrigated field trials in Egypt, Morocco and Tunisia. A wide range of barley germplasm (developed from African and European cultivars, adapted landraces and wild barleys) was tested, and positive traits were found in each gene pool. The contrasting environments of the three North African countries had major effects on plant/genotype performance. Genetic effects were also detected, as were genotype × environment interactions.A range of strategies were deployed to investigate the physiology and genetics of quantitative traits associated with field performance. Quantitative trait locus (QTL) analysis was performed using backcross lines, recombinant inbred lines and doubled haploid mapping populations. A detailed genetic map was generated in the Tadmor × (ER/Apm) recombinant inbred lines, an important mapping population specifically developed by ICARDA (Centre for Agricultural Research in Dry Areas) and CIMMYT (International Maize and Wheat Improvement Center) to study drought. Quantitative trait loci (QTLs) for grain yield and other important morphological and physiological traits were also identified in a population of doubled haploids derived from F2BCj plants from a cross between a cultivar and a wild barley accession. Significantly, the wild parental line was found to contribute a number of positive alleles for yield.Effects of major developmental genes could explain many of the responses observed. QTLs were found to cluster around major genes controlling flowering time (sghI), plant stature (sdwI and arie.GP) and ear type (vrsl), and it is highly likely that the associations represent pleiotropic effects. Some QTLs were associated with candidate genes such as dehydrins and rubisco activase. One of the most significant results was the identification and generation of material that out performed the best local standards in the three participating North African countries; the selected lines have now entered local breeding programmes. The strategies adopted provided information on physiological traits, genotypes and genetic markers that could be used for marker‐assisted selection. Target QTLs and their associated genetic markers may be deployed in marker assisted selection programmes to match crop phenology to the field environment.
Approaches to breeding for salinity tolerance ‐ a case study on Porteresia coarctata
Authors: LATHA R , SRINIVAS RAO C , SR SUBRAMANIAM H M , EGANATHAN P , SWAMINATHAN M S 
Published: July 2006

SummaryCereals are the world's major source of food for human nutrition. Among these, rice (Oryza sativa) is the most prominent and represents the staple diet for more than two‐fifths (2.4 billion) of the world's population, making it the most important food crop of the developing world (Anon., 2000a). Rice production in vast stretches of coastal areas is hampered due to high soil salinity. This is because rice is a glycophyte and it does not grow well under saline conditions. In order to increase rice production in these areas there is a need to develop rice varieties suited to saline environments. Research has shown that Porteresia coarctata, a highly salt tolerant wild relative of rice growing in estuarine soils, is an important material for transferring salt tolerant characteristics to rice. It is quite possible that Porteresia may be used as a parent for evolving better and truly salt resistant varieties. The inadequate results and the difficulties associated with conventional breeding techniques necessitate the use of the tools of crop biotechnology in unravelling some of the characteristics of Porteresia that have been highlighted in this report. In view of the limited resources available for increasing salinity tolerance to the breeders to wild rice germplasm, Porteresia is undoubtedly one of the key source species for elevating salinity tolerance in cultivated rice.
Biological activity of tree marigold, Tithonia diversifolia, on cowpea seed bruchid, Callosobruchus maculatus (Coleoptera: Bruchidae)
Authors: ADEDIRE C O , AKINNEYE J O 
Published: July 2006

SummaryThe powder and ethanol extract of Tithonia diversifolia leaves were tested for their efficacy at five different concentrations (0.0%, 0.5%, 1.0%, 1.5% and 2.0%) on bruchid mortality, oviposition and adult emergence of cowpea seed beetle Callosobruchus maculatus at ambient tropical storage conditions of temperature and relative humidity. Results showed that the leaf extract had a higher bioactivity on oviposition, adult emergence and mortality of C. maculatus. The mean number of eggs laid on seeds treated with extract was reduced from 20.7 in the solvent‐treated to 4.7 at 2%Tithonia extract concentration while adult emergence reduced from a mean of 92.2 in the solvent‐treated seeds to 72.2 at 2.0% extract treatment. Mortality was 100% at higher concentrations of 3%, 4% and 5% within 24 h of extract application but at lower concentrations mortality was 73.3% and 93.3% at 1% and 2%, respectively after 24 h. Fourty‐eight hours after application, 100% mortality of adult C. maculatus was obtained at all concentrations. The mean number of eggs laid was reduced from 41.3 in the untreated to 17.3 at 2.0% powder concentration while adult emergence dropped from 98.5% in the control to 74.2% at the highest powder concentration. The powder was effective at higher concentrations and longer exposure time. At 3%, 4% and 5%, 63–75% mortalities occurred within 24 h of application while at 48 h, mortality was 76–98% at 3–5% powder application rates. The results of this study revealed T. diversifolia as a potential candidate for bioinsecticide preparations because of antiovipositional, ovicidal and knockdown properties of its products, which have some volatile components.
Seasonal infectivity of Cacopsylla pruni, vector of European stone fruit yellows phytoplasma
Authors: CARRARO L , FERRINI F , LABONNE G , ERMACORA P , LOI NAZIA 
Published: July 2006

SummaryEpidemiology of European stone fruit yellows was studied by focussing on the life cycle and transmission characteristics of the vector Cacopsyllapruni. The proportion of both phytoplasma positive and inoculative insects was determined for the first C. pruni adults back colonising the stone fruit trees in spring and for the new generations of the vector, hatched at the beginning of summer. We showed that in spring, as soon as the insects moved to stone fruit trees from shelter plants, they were infective. After the vector fed on infected stone fruit trees, the proportion of phytoplasma positive insects increased. The new generation colonising Prunus species also acquired the phytoplasma from their hosts although several of these insects completed the latency period on secondary hosts. Results showed that the risk of natural transmission of European stone fruit yellows‐phytoplasma by C. pruni within orchards is high when the vector is present. These results have implications for the control of European stone fruit yellows.
Protein and oil concentration of soybean seed cultured in vitro using nutrient solutions of differing glutamine concentration
Authors: PIPOLO ANTONIO E , SINCLAIR THOMAS R , CAMARA GIL M S 
Published: July 2006

SummaryOil and protein are the most valuable components of soybean seed. Evidence indicates that growth and composition of soybean seed are controlled by supplies of carbon and nitrogen provided by the maternal plant to the seed, but it is difficult experimentally to control and quantify the precise amount of carbon and nitrogen provided to the seed by the whole plant. To examine whether oil and protein concentrations are affected by the supply of nitrogen to the seed, immature soybean seeds (Glycine max cv. Williams 82) were grown in vitro in nutrient solutions containing 20, 40, 60 or 80 mM of glutamine. The seeds were incubated in Erlenmeyer flasks for 8 days at 25°C. The rate of dry matter accumulation changed from 7.2 to 8.3 mg seed−1 day−1 as the glutamine concentration increased from 20 to 80 mM but the differences were not significant (P 0.05). Seed protein concentration increased as glutamine concentration increased from 294 mg g−1 at 20 mM glutamine to as high as 445 mg g−1 at 80 mM glutamine. Typical in vivo protein concentration of mature soybean seeds is about 400 mg g−1. Oil and protein concentrations were negatively correlated (r2= 0.44), which indicates that oil and protein synthesis are interrelated. Protein synthesis was favoured over oil synthesis when nitrogen became more abundant. The seeds used in this study clearly demonstrated a capacity to respond to nitrogen availability with changes in seed protein concentration.
The problems of sustainable water use in the Mediterranean and research requirements for agriculture
Authors: LARAUS J 
Published: July 2006

SummaryThis study addresses the sustainable use of water resources in the Mediterranean basin, particularly in the Southern and Eastern parts of the region, and the many problems generated by water scarcity and misuse. Water economy in the region is beset by two specific problems: high irrigation needs and changes in consumer demands (especially after population shifts from rural to urban areas and because of increasing tourism and industrialisation). The challenges presented by the water crisis are even greater because of growing populations and estimated future climatic changes in the region. The integrated management of limited water resources in the Southern and Eastern parts of the Mediterranean involves several areas of research. Those most directly related with agriculture concern improving water (and nutrient) use in agriculture through the management and breeding of irrigated and rain‐fed crops. However, these fields of research address only one face of a multi‐factorial equation that affects water sustainability in the region. Thus, other research fields include the design of comprehensive water policies and integrated planning, and technologies for advanced water treatment and re‐use. Moreover, local problems and socio‐economic aspects must be considered when addressing research issues.
Aerated subsurface irrigation water gives growth and yield benefits to zucchini, vegetable soybean and cotton in heavy clay soils
Authors: BHATTARAI S P , HUBER S , MIDMORE DAVID J 
Published: July 2006

SummaryInadequate oxygen concentration in the root zone is a constraint to plant performance particularly in heavy, compacted and/or saline soils. Sub‐surface drip irrigation (SDI) offers a means of increasing oxygen to plant roots in such soils, provided irrigation water can be hyper‐aerated or oxygenated. Hydrogen peroxide (HP) at the rate of 5 litre ha−1 at the end of each irrigation cycle was injected through SDI tape to a field‐grown zucchini (courgette) crop (Cucurbita pepo) on a saturated heavy clay soil in Queensland, Australia. Fruit yield, number and shoot weight increased by 25%, 29% and 24% respectively due to HP treatment compared to the control. Two pot experiments with vegetable soybean (Glycine max) and cotton (Gossypium hirsutum) compared the effectiveness of HP and air injection using a Mazzei air injector (a venturi), throughout the irrigation cycle in raising crop yield in a heavy clay soil kept at saturation or just under field capacity. Fresh pod yield of vegetable soybean increased by 82–96% in aeration treatments compared with the control. The yield increase was associated with more pods per plant and greater mean pod weight. Significantly higher above ground biomass and light interception were evident with aeration, irrespective of soil water treatment. Similarly cotton lint yield increased by 14–28% in aeration treatments compared with the control. The higher lint yield was associated with more squares and bolls per plant which accompanied greater above ground biomass and an increase in root mass, root length and soil respiration. Air injection and HP effected greater water use, but also brought about an enhancement of water use efficiency (WUE) for pod and lint yield, and increased leaf photosynthetic rate in both species but had no effect on transpiration rate and stomatal conductance per unit leaf area. Aeration‐induced enhanced root function was arguably responsible for greater fruit set and yield in all three crops, while in vegetable soybean greater canopy cover, radiation interception and total vegetative biomass were responsible for additional yield benefit. Increased aeration of the root zone in heavy clay soils employing either air injection or HP proved beneficial to SDI irrigated crops, irrespective of the soil water conditions, and can add value to grower investments in SDI.
Water uptake dynamics, photosynthesis and water use efficiency in field‐grown Medicago arborea and Medicago citrina under prolonged Mediterranean drought conditions
Authors: LEFI E , MEDRANO H , CIFRE J 
Published: July 2006

SummaryDrought is the main limiting factor of forage production in semi‐arid areas. Annual variation of soil water availability (SWA), predawn leaf water potential (Ψpd), stomatal conductance (g), photosynthesis rate (A) and the intrinsic water use efficiency (A/g) were examined under irrigation (control) and rain fed conditions in Palma de Mallorca (Spain) for two Mediterranean shrubs: Medicago arborea (M. arborea), with a wide distribution and Medicago citrina (M. citrina), an endemic species to the Balearic islands. Experimental conditions were typically Mediterranean, with low annual precipitation.In well‐irrigated plants, SWA and Ψpd were similar for both species throughout the year but higher g was observed in autumn and in spring‐summer. The photosynthesis rate was slightly higher in autumn and spring. Even though photosynthetic activity in M. arborea was higher than in M. citrina in spring, A/g was relatively higher for M. citrina for most of the year due to a lower transpiration rate.Under rain fed conditions, SWA dropped after February from 70% to 10–20%. Variations in plant water status, g and A were mainly dependent on SWA. Moreover, differences for water extraction and water use efficiency between species were found. Under moderate drought (SWA > 60%), g was more severely reduced than A and Ψpd (October‐March), as a consequence, A/g increased. Stomatal conductance variations for both species were more closely related to soil moisture rather than to leaf water status. Interestingly, M. citrina desiccated the soil more gradually and extracted water at deeper horizons (between 0.5 and 1 m). As a consequence, it maintained relatively higher Ψpdg and A than M. arborea throughout spring. For M. arborea, SWA declined more rapidly and leaf shedding in spring was much more substantial. When subjected to severe and prolonged summer drought (SWA < 50%), all parameters were severely reduced for both species and A had values near zero. Consequently, A/g was low and the senescence of the majority of leaves for M. arborea took place. On the basis of these results, M. citrina exhibits a higher water use efficiency under moderate drought.
Identification of Hordeum spontaneum QTL alleles improving field performance of barley grown under rainfed conditions
Authors: TALAMÉ V , SANGUINETI M C , CHIAPPARINO E , BAHRI H , BEN SALEM M , FORSTER B P , ELLIS R P , RHOUMA S , ZOUMAROU W , WAUGH R , TUBEROSA R 
Published: July 2006

SummaryAdvanced backcross QTL (AB‐QTL) analysis was deployed to identify allelic variation in wild barley (Hordeum vulgare ssp. spontaneum) of value in the improvement of grain yield and other agronomically important traits in barley (Hordeum vulgare ssp. vulgare) grown under conditions of water deficit in Mediterranean countries. A population of 123 double haploid (DH) lines obtained from BC1F2 plants derived from a cross between Barke (European two‐row cultivar) and HOR11508 (wild barley accession) were tested in replicated field trials, under varying conditions of water availability in Italy, Morocco and Tunisia, for seven quantitative traits. Significant QTL effects at one (P 0.001) or more trial sites (P 0.01) were identified for all traits. At 42 (52%) of the 80 putative QTLs identified, the allele increasing a “traits' value” was contributed by H. spontaneum. For example, though the majority (67%) of QTL alleles increasing grain yield were contributed by H. vulgare, H. spontaneum contributed the alleles increasing grain yield at six regions on chromosomes 2H, 3H, 5H and 7H. Among them, two QTLs (associated to Bmac0093 on chromosome 2H and to Bmac0684 on chromosome 5H) were identified in all three locations and had the highest additive effects. The present study shows the validity of deploying AB‐QTL analysis for identifying favourable QTL alleles from wild germplasm and indicates its potential as an enhancement strategy for the genetic improvement of cultivars better adapted to drought‐prone environments.
Effect of salinisation of soil on growth and macro‐ and micro‐nutrient accumulation in seedlings of Acacia catechu (Mimosaceae)
Authors: RAMOLIYA P J , PATEL H M , PANDEY A N 
Published: July 2006

SummaryThe effects of salinisation of soil on Acacia catechu (Mimosaceae) were studied by means of emergence and growth of seedlings and pattern of mineral accumulation. A mixture of chlorides and sulphates of Na, K, Ca and Mg was added to the soil and salinity was maintained at 4.1, 6.3, 8.2,10.1 and 12.2 dSm−1. A negative relationship between proportion of seed germination and salt concentration was obtained. Seedlings did not emerge when soil salinity exceeded 10.1 dSm−1. Results suggested that this tree species is salt tolerant at the seed germination stage. Seedlings survived and grew up to soil salinity of 10.1 dSm−1, which suggests that this species is salt tolerant at the seedling stage too. Elongation of stem and root was retarded by increasing salt stress. Among the tissues, young roots and stem were most tolerant to salt stress and were followed by old roots and leaves, successively. Leaf tissue exhibited maximum reduction in dry mass production in response to increasing salt stress. However, production of young roots and death of old roots were found to be continuous and plants apparently use this process as an avoidance mechanism to remove excess ions and delay onset of ion accumulation in this tissue. This phenomenon, designated “fine root turnover”, is of importance to the mechanisms of salt tolerance. Plants accumulated Na in roots and were able to regulate transfer of Na ions to leaves. Stem tissues were a barrier for translocation of Na from root to leaf. Moreover, K was affected in response to salinity; it rapidly decreased in root tissues with increased salinisation. Nitrogen content decreased in all tissues (leaf, stem and root) in response to low water treatment and salinisation of soil. Phosphorus content significantly decreased, while Ca increased in leaves as soil salinity increased. Changes in tissue and whole plant accumulation patterns of the other elements tested, as well as possible mechanisms for avoidance of Na toxicity in this tree species during salinisation, are discussed.
Identification and distribution of viruses infecting sweet potato in Kenya
Authors: ATEKA E M , NJERU R W , KIBARU A G , KIMENJU J W , BARG E , GIBSON R W , VETTEN H J 
Published: July 2006

SummaryFour hundred and forty‐eight symptomatic and 638 asymptomatic samples were collected from sweet potato fields throughout Kenya and analysed serologically using antibodies to Sweet potato feathery mottle virus (SPFMV), Sweet potato chlorotic stunt virus (SPCSV), Sweet potato mild mottle virus (SPMMV), Cucumber mosaic virus (CMV), Sweet potato chlorotic fleck virus (SPCFV), Sweet potato latent virus (SwPLV), Sweet potato caulimo‐like virus (SPCaLV), Sweet potato mild speckling virus (SPMSV) and C‐6 virus in enzyme‐linked immunosorbent assays (ELISA). Only SPFMV, SPMMV, SPCSV, and SPCFV were detected. Ninety‐two percent and 25% of the symptomatic and asymptomatic plants respectively tested positive for at least one of these viruses. Virus‐infected plants were collected from 89% of the fields. SPFMV was the most common and the most widespread, detected in 74% of the symptomatic plants and 86% of fields surveyed. SPCSV was also very common, being detected in 38% of the symptomatic plants and in 50% of the fields surveyed. SPMMV and SPCFV were detected in only 11% and 3% of the symptomatic plant samples respectively. Eight different combinations of these four viruses were found in individual plants. The combination SPFMV and SPCSV was the most common, observed in 22% of symptomatic plants. Virus combinations were rare in the asymptomatic plants tested. Incidence of virus infection was highest (18%) in Kisii district of Nyanza province and lowest (1%) in Kilifi and Malindi districts of Coast province.
Plant pathogen diagnostics: immunological and nucleic acid‐based approaches
Authors: WARD ELAINE , FOSTER SIMON J , FRAAIJE BART A , MCCARTNEY H ALASTAIR 
Published: July 2006

SummaryAccurate disease diagnosis and precise identification of any pathogens involved is an essential prerequisite for understanding plant diseases and controlling them effectively. Traditional methods of identifying plant pathogens can be slow and inconclusive, and this has prompted the search for alternative diagnostic techniques. Here, we review recent developments in antibody‐based and nucleic acid‐based diagnostic methods, and their applications in plant pathology. We also highlight some new developments in diagnostics that are likely to make an impact in the future.
Can genetic manipulation of plant nitrogen assimilation enzymes result in increased crop yield and greater N‐use efficiency? An assessment
Authors: ANDREWS M , LEA P J , RAVEN J A , LINDSEY K 
Published: July 2006

SummaryThe literature on the relations between plant nitrogen (N) assimilation enzymes and plant/crop N assimilation, growth and yield is reviewed to assess if genetic manipulation of the activities of N assimilation enzymes can result in increased yield and/or increased N use efficiency. The available data indicate that (I) levels of N assimilation enzymes do not limit primary N assimilation and hence yield; (II) root or shoot nitrate assimilation can have advantages under specific environmental conditions; (III) for cereals, cytosolic glutamine synthetase (GS1) is a key enzyme in the mobilisation of N from senescing leaves and its activity in senescing leaves is positively related to yield; and (TV) for rice (Oryza sativd), NADH‐glutamate synthase (NADH‐GOGAT) is important in the utilisation of N in grain filling and its activity in developing grains is positively related to yield. In our opinion, selection of plants, from either a genetically manipulated population or genetic resources, with expression of nitrate reductase/nitrite reductase primarily in the root or shoot should increase plant/crop growth and hence yield under specific environmental conditions. In addition for cereals the selection of plants with high GS1 in senescing leaves and in some cases high NADH‐GOGAT in developing grains could help maximise the retrieval of plant N in seeds.