Showing papers on "Cultivar published in 2014"

Image-based phenotyping for non-destructive screening of different salinity tolerance traits in rice

Abstract: Soil salinity is an abiotic stress wide spread in rice producing areas, limiting both plant growth and yield. The development of salt-tolerant rice requires efficient and high-throughput screening techniques to identify promising lines for salt affected areas. Advances made in image-based phenotyping techniques provide an opportunity to use non-destructive imaging to screen for salinity tolerance traits in a wide range of germplasm in a reliable, quantitative and efficient way. However, the application of image-based phenotyping in the development of salt-tolerant rice remains limited. A non-destructive image-based phenotyping protocol to assess salinity tolerance traits of two rice cultivars (IR64 and Fatmawati) has been established in this study. The response of rice to different levels of salt stress was quantified over time based on total shoot area and senescent shoot area, calculated from visible red-green-blue (RGB) and fluorescence images. The response of rice to salt stress (50, 75 and 100 mM NaCl) could be clearly distinguished from the control as indicated by the reduced increase of shoot area. The salt concentrations used had only a small effect on the growth of rice during the initial phase of stress, the shoot Na+ accumulation independent phase termed the ‘osmotic stress’ phase. However, after 20 d of treatment, the shoot area of salt stressed plants was reduced compared with non-stressed plants. This was accompanied by a significant increase in the concentration of Na+ in the shoot. Variation in the senescent area of the cultivars IR64 and Fatmawati in response to a high concentration of Na+ in the shoot indicates variation in tissue tolerance mechanisms between the cultivars. Image analysis has the potential to be used for high-throughput screening procedures in the development of salt-tolerant rice. The ability of image analysis to discriminate between the different aspects of salt stress (shoot ion-independent stress and shoot ion dependent stress) makes it a useful tool for genetic and physiological studies to elucidate processes that contribute to salinity tolerance in rice. The technique has the potential for identifying the genetic basis of these mechanisms and assisting in pyramiding different tolerance mechanisms into breeding lines.

Effect of PEG-induced drought stress on seed germination of four lentil genotypes

Abstract: Seeds of four lentil genotypes (Castelluccio, Eston, Pantelleria, and Ustica) were subjected to five levels (0, 10, 15, 18, and 21%) of polyethylene glycol (PEG-6000). Germination percentage, root length, tissue water content (WC), α- and β-amylases, α-glucosidase activities, and osmolyte content were evaluated at 24, 48, and 72 h after starting the germination test. Water stress reduced seed germination percentage, root length, and seedling WC in all cultivars to different extent. The increase in proline content and total soluble sugars was greater for Eston and Castelluccio compared to the other genotypes. The activity of the enzymes involved in the germination process decreased in all cultivars; the activities of α-amylase and α-glucosidase were most negatively affected by osmotic stress, mainly in the drought sensitive Ustica and Pantelleria. Overall, Eston and Castelluccio were able to express greater drought tolerance and consequently could be used as a valuable resource for breeding programs.

The endophyte Enterobacter sp. FD17: a maize growth enhancer selected based on rigorous testing of plant beneficial traits and colonization characteristics

Abstract: With the aim to select powerful microbial strains to be used for the enhancement of maize yield and resistance to abiotic and biotic stresses, we tested five endophytic bacterial strains previously isolated from maize roots. A range of different laboratory assays in regard to potential plant growth promotion was performed and strains were further evaluated for improving growth of five maize cultivars under axenic and natural soil conditions. Endophytic colonization was an additional component in our selection process as it is of high importance for an inoculant strain to efficiently colonize the plant environment. All strains had the potential to improve maize seedling growth under axenic conditions. Enterobacter sp. strain FD17 showed both the highest growth-promoting activity under axenic conditions as well as colonization capacity. FD17 was therefore selected for further plant tests in a net house, in which two different maize cultivars were grown in large pots until ripening and subjected to outdoor climatic conditions. Results showed that inoculation significantly increased plant biomass, number of leaves plant−1, leaf area, and grain yield up to 39 %, 14 %, 20 %, and 42 %, respectively, as compared to the un-inoculated control. Similarly, inoculation also improved the photochemical efficiency of photosystem II (PSII) of maize plant and reduced the time needed for flowering. We also confirmed that strain FD17 is able to colonize the rhizosphere, roots and stems. Based on rigorous testing, Enterobacter sp. strain FD17 showed the highest potential to promote growth and health of maize grown under natural conditions. This study suggested that in vitro plant growth-promoting traits and potential of maize seedling growth promotion by bacterial endophytes could be used for the selection of potential inoculant strains subjected for further testing as bio-inoculant under field conditions.

Integration of cultivar resistance and fungicide application for control of wheat stripe rust

Abstract: Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most destructive diseases of wheat. The disease is mainly controlled by growing resistant cultivars and applying fungicides when necessary. To determine potential yield loss and fungicide response, major cultivars grown in the US Pacific Northwest and susceptible checks were tested in complete split-block design experiments. From 2002 to 2012, stripe rust caused yield losses ranging from 18% to more than 90% and from 5% to more than 50% with an average of 44% and 33% on susceptible winter and spring wheat checks, respectively. Without fungicide application, the commercially grown cultivars with various levels of stripe rust resistance could reduce potential yield losses to 2–21%, with an average of 8% for winter wheat, and to 0–27% with an average of 13% for spring wheat. Significant or insignificant effects of fungicide applications on yield increase were determined for each cultivar, and the results were used to guide stri...

Guidelines to use tomato in experiments with a controlled environment.

Abstract: Domesticated tomato (Solanum lycopersicum) is the most important horticultural crop worldwide. Low polymorphism at the DNA level conflicts with the wealth of morphological variation. Fruits vary widely in size, shape and colour. In contrast, genetic variation between the 16 wild relatives is tremendous. Several large seed banks provide tomato germplasm for both domesticated and wild accessions of tomato. Recently, the genomes of the inbred cultivar “Heinz 1706” (≈900 Mb) and S. pimpinellifolium (739 Mb) were sequenced. Genomic markers and genome re-sequencing data are available for >150 cultivars and accessions. Transformation of tomato is relatively easy and T-DNA insertion line collections are available. Tomato is widely used as a model crop for fruit development but also for diverse physiological, cellular, biochemical, molecular and genetic studies. It can be easily grown in greenhouses or growth chambers. Plants grow, flower, and develop fruits well at daily light lengths between 8-16 hours. The required daily light integral of an experiment depends on growth stage and temperature investigated. Temperature must be 10-35°C, relative humidity 30-90 % and CO2 concentration 200-1500 µmol mol-1. Temperature determines the speed of the phenological development while daily light integral and CO2 concentration affect photosynthesis and biomass production. Seed to seed cultivation takes 100 days at 20°C and can be shortened or delayed by temperature. Tomato may be cultivated in soil, substrates, or aeroponically without any substrate. Root volume and water uptake requirements are primarily determined by transpiration demands of the plants. Many nutrient supply recipes and strategies are available to ensure sufficient supply as well as specific nutrient deficits/surplus. Using appropriate cultivation techniques makes tomato a convenient model plant for researchers, even for beginners.

Association analysis of fiber quality traits and exploration of elite alleles in Upland cotton cultivars/accessions (Gossypium hirsutum L.)

Abstract: Exploring the elite alleles and germplasm accessions related to fiber quality traits will accelerate the breeding of cotton for fiber quality improvement. In this study, 99 Gossypium hirsutum L. accessions with diverse origins were used to perform association analysis of fiber quality traits using 97 polymorphic microsatellite marker primer pairs. A total of 107 significant marker-trait associations were detected for three fiber quality traits under three different environments, with 70 detected in two or three environments and 37 detected in only one environment. Among the 70 significant marker-trait associations, 52.86% were reported previously, implying that these are stable loci for target traits. Furthermore, we detected a large number of elite alleles associated simultaneously with two or three traits. These elite alleles were mainly from accessions collected in China, introduced to China from the United States, or rare alleles with a frequency of less than 5%. No one cultivar contained more than half of the elite alleles, but 10 accessions were collected from China and the two introduced from the United States did contain more than half of these alleles. Therefore, there is great potential for mining elite alleles from germplasm accessions for use in fiber quality improvement in modern cotton breeding.

Soybean yield partitioning changes revealed by genetic gain and seeding rate interactions

Abstract: Soybean [Glycine max (L.) Merr.] yield has increased during the past century; however, little is understood about the morphological parameters that have contributed most to yield gain. We conducted field studies to determine relationships between genetic gain of soybean yield and seeding rate. The hypothesis was newer cultivars would express higher yield than older cultivars when grown in higher plant populations. A total of 116 soybean cultivars equally representing Maturity Groups (MGs) II and III released over the last 80 yr were evaluated at high and low seeding rates in Wisconsin, Minnesota, Illinois, and Indiana. Seeding rates were 445,000 and 148,000 seeds ha–¹ resulting in 311,000 and 94,000 plants ha–¹ (high and low, respectively). Seed yield was greater for the high seeding rate vs. low seeding rate throughout all cultivars and years of release, but the difference was larger in newer cultivars. The differences observed primarily came from an increased number of pods and seeds plant–¹. However, newer cultivars grown in low seeding rates increased per plant yield linearly by 0.118 (± 0.02)x– 208.0 g plant–¹, where x = year-of-release, which was three times greater than at the high seeding rate. The greater yield trend came from seeds produced on plant branches. Therefore, newer cultivars produce more compensatory yield on plant branches under lower plant populations than older cultivars, so over the last 80 yr there has been a diminishing response to the expected yield penalty from reduced plant density.

Phenotyping soybean plants transformed with rd29A:AtDREB1A for drought tolerance in the greenhouse and field

Abstract: The development of drought tolerant plants is a high priority because the area suffering from drought is expected to increase in the future due to global warming One strategy for the development of drought tolerance is to genetically engineer plants with transcription factors (TFs) that regulate the expression of several genes related to abiotic stress defense responses This work assessed the performance of soybean plants overexpressing the TF DREB1A under drought conditions in the field and in the greenhouse Drought was simulated in the greenhouse by progressively drying the soil of pot cultures of the P58 and P1142 lines In the field, the performance of the P58 line and of 09D-0077, a cross between the cultivars BR16 and P58, was evaluated under four different water regimes: irrigation, natural drought (no irrigation) and water stress created using rain-out shelters in the vegetative or reproductive stages Although the dehydration-responsive element-binding protein (DREB) plants did not outperform the cultivar BR16 in terms of yield, some yield components were increased when drought was introduced during the vegetative stage, such as the number of seeds, the number of pods with seeds and the total number of pods The greenhouse data suggest that the higher survival rates of DREB plants are because of lower water use due to lower transpiration rates under well watered conditions Further studies are needed to better characterize the soil and atmospheric conditions under which these plants may outperform the non-transformed parental plants

Efficient Agrobacterium transformation of elite wheat germplasm without selection

Abstract: A previously reported Agrobacterium tumefaciens transformation system that transformed wheat cultivar Fielder at high efficiency was shown to also transform eight out of nine Triticum aestivum (hexaploid wheat) cultivars tested and two Triticum turgidum (durum wheat) cultivars. Transformation efficiencies of these wheat lines ranged from 1.5 to 51 %. Included amongst this germplasm were elite Australian hexaploid wheat cultivars that are currently in commercial cultivation and two of these cultivars, Gladius and Westonia, were transformed at 32 and 45 % efficiency, respectively. Similar high transformation efficiencies were observed for durum wheat cultivars Kronos (51 %) and Stewart (26 %). This highly efficient transformation system was used to generate transgenic plants in the absence of selection and high heritability of unselected transgenes was observed. Selectable marker free transgenic wheat plants were produced at 3 % efficiency. These data demonstrate highly efficient Agrobacterium transformation of diverse wheat germplasm, including elite cultivars, which enables routine production of selectable marker free transgenics.

Impact of Methyl jasmonate on antioxidant activity and some biochemical aspects of maize plant grown under water stress condition.

Abstract: A pot-culture study was undertaken to investigate the possible role of Methyl jasmonate (MeJA)-treatment on the earlier vegetative growth stage and different chemical constituents of maize cultivar (Giza-2) plants subjected to water stress. The grains were divided into two groups: first group was pre-soaked in water, and the second one was pre-soaked in 50 μM MeJA for 8 h. The plants were subjected to different levels of water field capacity (WFC) 65%, 55% and 45%. The results showed that pre-soaking maize grains with MeJA led to increases in plant growth criteria evident in terms of plant height, fresh and dry weight of plant. The pigment levels concomitantly with total carbohydrates, total soluble sugar, polysaccharides, as well as free amino acids, proline and total protein content were markedly increased. Moreover, the application of the investigated MeJA significantly improved growth hormone in terms of IAA. In contrast ABA level was markedly declined in maize plant. The activities of oxidative CAT, POX and SOD were also increased with MeJA. In addition, the N, P and K content was increased significantly in shoot. As a conclusion, soaking maize grains with MeJA could alleviate the harmful effects of water stress.

Temperature Effect on Yield and Yield Components of Different Rice Cultivars in Flowering Stage

Abstract: In order to study the effect of cold stress in flowering stage on yield and yield components of different rice cultivars, an experiment was performed as split plot factorial based on completely randomized design (CRD) in greenhouse of deputy of rice research institute of Iran (Amol) in 2010, in three repetitions. Treatment included 5 varieties as main factors that included cultivars of shirudi, fajr, local tarom, hybrid, and line 843. Two levels of temperatures (13°C, stress temperature) and (32°C, normal temperature, control) along with flowering stage were selected as two subfactors. Three seedlings were planted in each plot. The cold stress was done in flowering stage with holding pots at 13°C for 15 days. Results showed that low temperature had significant effect in level of 1 percent on all characters, such as the number of panicles, the length of panicle, and the number of full, empty, and total grains; as a result, yield had caused significant reduction. Interaction between temperature and varieties showed that most tolerant variety in relation to temperature stress along with least percentage yield (19%) is shirudi variety and the most sensitive one with most percentage of yield decrease (29%) was local tarom variety.

Agronomic model uses to predict cultivar performance in various environments and cropping systems. A review

Abstract: The diversity of growing conditions and the development of new outlets for agricultural products favour a diversity of crop management systems requiring various cultivars, with specific characteristics. Genotype performance is usually assessed through multi-environment trials comparing a variable number of genotypes grown in a wide range of soils, climatic conditions and cropping systems. Field experiments show empirical evidence for the interactions between genotype, environment and cropping system. However, such interactions are rarely taken into account to design ideotypes or for cultivar assessment, or in the definition of crop management plans adapted to cultivars. Agronomic models, built to simulate the dynamic response of crops to their environment, and thus to techniques which modify it, appear to be appropriate tools to evaluate and predict these interactions. This paper reviews the three main uses of model-based predictions of the interactions between genotype, environment and cropping system: definition of breeding targets, characterisation of the environments in cultivar experiments and support for the choice of the best cultivar to grow in a given situation. Models specifically allow understanding the influence of one or a combination of specific traits on performances and long-term ecological impacts. We show that a diversity of models is required, from physiologically based crop models to agroecology-based cropping system or landscape models, able to account well for farmers’ practices. A way of taking cultivars into account in crop models is proposed, based on three main steps: the choice of the model, the identification and estimation of its cultivar parameters, and testing the model for decision support. Finally, the analysis of the limitations for wider use of crop models in variety breeding and assessment addresses some major questions for future research.

Genotypic variability for antioxidant and quality parameters among tomato cultivars, hybrids, cherry tomatoes and wild species

Abstract: BACKGROUND Wide germplasm diversity and transferability of antioxidant parameters is the primary requirement for the development of high-antioxidant tomato cultivars. The present study was conducted to screen tomato genotypes including hybrids, varieties, cherry tomatoes, wild species, elite germplasm lines, interspecific hybrids and backcross populations for antioxidant activity and other quality parameters to select high-antioxidant lines with good total soluble solids (TSS) for further usage in crop improvement programmes. RESULTS Wild species and interspecific hybrids between LA-1777 (Solanum habrochaites) and an elite genotype 15SBSB recorded very high antioxidant capacity (FRAP), DPPH radical-scavenging ability, and high phenols and flavonoids. Interspecific hybrids also recorded very high total soluble solids (TSS). Significantly higher total carotenoids, lycopene and vitamin C were observed in IIHR-249-1 with moderately higher TSS. Cherry tomato lines IIHR-2866, 2865 and 2864 recorded four to five times more β-carotene than commercial hybrids/varieties. CONCLUSION Tomato line IIHR-249-1 can be used for improving antioxidant capacity, total carotenoids and lycopene in tomato breeding programmes. Cherry tomato lines IIHR-2866, 2865 and 2864 can be used for improving β-carotene content. LA-1777 and interspecific hybrids could be used for developing tomato lines rich in antioxidants as well as TSS. © 2013 Society of Chemical Industry

Effect of Different Levels of Nitrogen and Phosphorus on the Phenology and Yield of Maize Varieties

Abstract: An experiment was conducted at Malakabad (Gadera) Dargai Malak and KPK to study the effect of different levels of nitrogen and phosphorus on the yield of maize varieties in randomize complete block design with split plot arrangement. Different fertilization treatments (0:0, 100:0, 100:50, 100:100, 150:0, 150:50, 150:100, 150:150 N:P kg·ha-1) were assigned to main plot while, maize varieties (Azam, Jalal and local) were kept in sub-plots. Data regarding emergence m-2, days to emergence, days to tasseling, days to silking, number of cobs plant-1, plant height, grains cob-1, 1000-grain weight and grain yield were recorded. Emergence m-2, days to emergence, days to tasseling, days to silking, plant ha-1 at harvest were not significantly affected by different levels of nitrogen and phosphorus while number of cob plant-1, thousand grains weight, plant height, grains cob-1 and grain yield were significantly affected. Maximum grain yield (5356 kg·ha-1) was recorded in Jalal variety, when it was fertilized with 150:100 N:P kg·ha-1. Of the factors included in this study, maize cultivars and NP fertilization treatments were dominant in determining grain yield as well as its related components, suggesting that cultivar selection and optimum fertilization are effective strategies to improve grain yield. However, multiplication and multi-year studies are required to test these results using different cultivars under varying edaphic and climatic conditions.

Over-expression of the Arabidopsis proton-pyrophosphatase AVP1 enhances transplant survival, root mass, and fruit development under limiting phosphorus conditions

Abstract: Phosphorus (P), an element required for plant growth, fruit set, fruit development, and fruit ripening, can be deficient or unavailable in agricultural soils. Previously, it was shown that over-expression of a proton-pyrophosphatase gene AVP1/AVP1D (AVP1DOX) in Arabidopsis, rice, and tomato resulted in the enhancement of root branching and overall mass with the result of increased mineral P acquisition. However, although AVP1 over-expression also increased shoot biomass in Arabidopsis, this effect was not observed in tomato under phosphate-sufficient conditions. AVP1DOX tomato plants exhibited increased rootward auxin transport and root acidification compared with control plants. AVP1DOX tomato plants were analysed in detail under limiting P conditions in greenhouse and field trials. AVP1DOX plants produced 25% (P=0.001) more marketable ripened fruit per plant under P-deficient conditions compared with the controls. Further, under low phosphate conditions, AVP1DOX plants displayed increased phosphate transport from leaf (source) to fruit (sink) compared to controls. AVP1DOX plants also showed an 11% increase in transplant survival (P<0.01) in both greenhouse and field trials compared with the control plants. These results suggest that selection of tomato cultivars for increased proton pyrophosphatase gene expression could be useful when selecting for cultivars to be grown on marginal soils.

Influence of rootstocks on growth, yield, fruit quality and leaf mineral element contents of pear cv. 'Santa Maria' in semi-arid conditions

Abstract: Rootstocks play an essential role to determining orchard performance of fruit trees. Pyrus communis and Cydonia oblonga are widely used rootstocks for European pear cultivars. The lack of rootstocks adapted to different soil conditions and different grafted cultivars is widely acknowledged in pear culture. Cydonia rootstocks (clonal) and Pyrus rootstocks (seedling or clonal) have their advantages and disadvantages. In each case, site-specific environmental characteristics, specific cultivar response and production objectives must be considered before choosing the best rootstock. In this study, the influence of three Quince (BA 29, Quince A = MA, Quince C = MC) and a local European pear seedling rootstocks on the scion yield, some fruit quality characteristics and leaf macro (N, P, K, Ca and Mg) and micro element (Fe, Zn, Cu, Mn and B) content of ‘Santa Maria’ pear (Pyrus communis L.) were investigated. Trees on seedling rootstock had the highest annual yield, highest cumulative yield (kg tree−1), largest trunk cross-sectional area (TCSA), lowest yield efficiency and lowest cumulative yield (ton ha−1) in the 10th year after planting. The rootstocks had no significant effect on average fruit weight and fruit volume. Significantly higher fruit firmness was obtained on BA 29 and Quince A. The effect of rootstocks on the mineral element accumulation (N, K, Ca, Mg, Fe, Zn, Cu, Mn and B) was significant. Leaf analysis showed that rootstocks used had different mineral uptake efficiencies throughout the early season. The results showed that the rootstocks strongly affected fruit yield, fruit quality and leaf mineral element uptake of ‘Santa Maria’ pear cultivar. Pear seedling and BA 29 rootstock found to be more prominent in terms of several characteristics for ‘Santa Maria’ pear cultivar that is grown in highly calcareous soil in semi-arid climate conditions. We determined the highest N, P (although insignificant), K, Ca, Mg, Fe and Cu mineral element concentrations on the pear seedling and BA 29 rootstocks. According to the results, we recommend the seedling rootstock for normal density plantings (400 trees ha−1) and BA 29 rootstock for high-density plantings (800 trees ha−1) for ‘Santa Maria’ pear cultivar in semi-arid conditions.

Isoflavone Content of Soybean Cultivars from Maturity Group 0 to VI Grown in Northern and Southern China.

Abstract: Soybean isoflavone content has long been considered to be a desirable trait to target in selection programs for their contribution to human health and plant defense systems. The objective of this study was to determine isoflavone concentrations of various soybean cultivars from maturity groups 0 to VI grown in various environments and to analyze their relationship to other important seed characters. Forty soybean cultivars were grown in replicated trials at Wuhan and Beijing of China in 2009/2010 and their individual and total isoflavone concentrations were determined by HPLC. Their yield and quality traits were also concurrently analyzed. The isoflavone components had abundant genetic variation in soybean seed, with a range of coefficient variation from 45.01% to 69.61%. Moreover, individual and total isoflavone concentrations were significantly affected by cultivar, maturity group, site and year. Total isoflavone concentration ranged from 551.15 to 7584.07 μg g−1, and averaged 2972.64 μg g−1 across environments and cultivars. There was a similar trend regarding the isoflavone contents, in which a lower isoflavone concentration was generally presented in early rather than late maturing soybean cultivars. In spite of significant cultivar × year × site interactions, cultivars with consistently high or low isoflavone concentrations across environments were identified, indicating that a genetic factor plays the most important role for isoflavone accumulation. The total isoflavone concentration had significant positive correlations with plant height, effective branches, pods per plant, seeds per plant, linoleic acid and linolenic acid, while significant negative correlations with oleic acid and oil content, indicating that isoflavone concentration can be predicted as being associated with other desirable seed characteristics.

Effects of grapevine cultivar, rootstock and clone on esca disease

Abstract: Esca is one of the main causes of reduction of production, plant decline and death in vineyards of most viticultural areas of the World. We determined the foliar esca symptoms on a range of grapevine cultivars in three central-eastern Italian vineyards during summer 2008, characterized by conducive conditions for the disease. In vineyard AP1, the incidence of symptomatic plants was recorded for 67 Vitis vinifera cultivars. Among white-berried cultivars, Passerina, Sauvignon blanc, Manzoni bianco, and Riesling, had highest incidence of symptomatic plants (28–35 %), while cvs. Chiapparu, Grechetto, Perdea, Verdicchio, Fiano and Pinot blanc had lowest (0–5 %). Among red-berried cultivars, Rebo had highest incidence of symptomatic plants (>35 %), with lowest for cvs. Lacrima, Brugentile, Sirah, and Limberger (0 %), followed by Gallioppo, Merlot, and Nebbiolo (<5 %). However, mean values of symptomatic plants among red and white cultivars were similar. The six cultivars monitored in vineyard AP2 confirmed this cultivar susceptibility ranking. Furthermore, in vineyard AN1, incidence of esca symptoms on seven cultivars grafted onto different rootstock was recorded. Cvs. Fiano and Sauvignon grafted onto SO4 showed higher disease incidence than combinations with 1103P. This result can be ascribed to the higher drought resistance of 1103P as compared to SO4, supporting the hypothesis that esca symptoms occur mostly in stressed plants. Significant differences in the symptom expression were recorded just among clones of Sauvignon, while they were not found in Chardonnay, Riesling and Pinot blanc. Our data give useful information for growers in planning cultivar/rootstock combination choice for new vineyards, and can provide an idea of possible evolution of esca along time in an already established vineyard.

Heat-tolerant rice cultivars retain grain appearance quality under free-air CO2 enrichment

Abstract: Background Heat-tolerant rice cultivars have been developed as a countermeasure to poor grain appearance quality under high temperatures. Recent studies showed that elevated CO2 concentrations (E-[CO2]) also reduce grain quality. To determine whether heat-tolerant cultivars also tolerate E-[CO2], we conducted a free-air CO2 enrichment (FACE) experiment with 12 rice cultivars differing in heat tolerance.

Diversity of crop development traits and nitrogen use efficiency among potato cultivars grown under contrasting nitrogen regimes

Abstract: Potato (Solanum tuberosum L.) requires abundant nitrogen (N) to perform well and has low nitrogen use efficiency (NUE). We assessed phenotypic variation among 189 potato cultivars for NUE and the association between NUE and ecophysiological variables describing canopy development (CDv), under high and low N input. In 2009 and 2010, 189 cultivars were grown with N supply (soil N + fertiliser N) of 75 or 180 kg N/ha at Bant, the Netherlands. CDv was assessed weekly as the percentage of soil covered by green potato leaves (%SC). Data were analysed using a model that described CDv as a function of thermal time, based on the Beta function and estimates of cardinal temperatures. Nitrogen significantly affected model-derived, biologically relevant, curve-fit parameters for each cultivar. The t 1 (i.e., thermal time required to reach maximum soil cover (Vx)) was higher at low than at high N. Other parameters were higher at high than at low N, especially Vx and the period over which it was maintained. Nitrogen also affected tuber dry matter yield, tuber size and weight distributions, N content and N uptake but not tuber dry matter percentage. The total area under the %SC curve was highly correlated with yield in both years. Cultivars performing well under high N also performed well under low N. There was large variation in NUE component traits among cultivars; maturity type partially explained this variation. Variables of the CDv model captured this variation, N effects on light interception and its correlation with yield.

Effect of foliar application of bio-stimulants on growth, yield, components, and storability of garlic (Allium sativum L.).

Abstract: Increasing garlic yield and improving bulb quality are essential aims for growers to fulfill the requirements of the market and the consumers. Two field experiments were carried out during two successive seasons; 2010/2011 and 2011/2012 at a private farm to find out the influence of some bio-stimulants i.e., ascorbic acid, dry yeast, amino acids (Ruter and Total), seaweed extract (Alga 600) and Spirulina extract (Arthospira fusiformis) on plant growth, yield, yield components and storability of garlic plants "Balady" cultivar. One month after planting, foliar applications of bio-stimulants were applied, and repeated 3 times at 15 days intervals throughout the growing season. The design of the experiment was a complete randomized blocks (CRB) with three replicates. Results indicated that foliar application of Amino Total (1.2 ml l -1 ) effectively increased plant height compared to all treatments and control. Number of leaves per plant was the least (9 and 9.5) in control plants in both seasons. Application of yeast (2 g l -1 ) or amino total (1.2 ml l -1 ) showed the heaviest bulb weight (67.7, 72.0 and 69.5, 66.6 g) in the first and second season, respectively. Weight loss of