Posts Tagged ‘wheat’

A high density GBS map of bread wheat and its application for dissecting complex disease resistance traits

Posted by gabrielamartinez on , in Journal Articles

56897Authors: Huihui Li, Vikram, P., Singh, R.P., Carling, J., Song, J., Burgueño, J., Bhavani, S., Huerta Espino, J., Payne, T.S., Sehgal, D., Wenzl, P., Sukhwinder-Singh.

Published in: BMC Genomics, 16: 216, 2015.


 

Background: Genotyping-by-sequencing (GBS) is a high-throughput genotyping approach that is starting to be used in several crop species, including bread wheat. Anchoring GBS tags on chromosomes is an important step towards utilizing them for wheat genetic improvement. Here we use genetic linkage mapping to construct a consensus map containing 28644 GBS markers.

Results: Three RIL populations, PBW343 × Kingbird, PBW343 × Kenya Swara and PBW343 × Muu, which share a common parent, were used to minimize the impact of potential structural genomic variation on consensus-map quality. The consensus map comprised 3757 unique positions, and the average marker distance was 0.88 cM, obtained by calculating the average distance between two adjacent unique positions. Significant variation of segregation distortion was observed across the three populations. The consensus map was validated by comparing positions of known rust resistance genes, and comparing them to wheat reference genome sequences recently published by the International Wheat Genome Sequencing Consortium, Rye and Ae. tauschii genomes. Three well-characterized rust resistance genes (Sr58/Lr46/Yr29, Sr2/Yr30/Lr27, and Sr57/Lr34/Yr18) and 15 published QTLs for wheat rusts were validated with high resolution. Fifty-two per cent of GBS tags on the consensus map were successfully aligned through BLAST to the right chromosomes on the wheat reference genome sequence.

Conclusion: The consensus map should provide a useful basis for analyzing genome-wide variation of complex traits. The identified genes can then be explored as genetic markers to be used in genomic applications in wheat breeding.

First Report of Fusarium redolens Causing Crown Rot of Wheat (Triticum spp.) in Turkey

Posted by gabrielamartinez on , in Journal Articles

56885Authors: Gebremariam, E.S.; Karakaya, A.; Erginbas-Orakci, G.; Dababat, A.A.; Sharma-Poudyal, D.; Paulitz, T.C.

 Published in: Plant Disease, In press.

Fusarium crown rot, caused by a complex of Fusarium spp., is a yield-limiting disease of wheat world-wide, especially in dry Mediterranean climates. In order to identify Fusarium species associated with crown rot of wheat, a survey was conducted in summer 2013 in the major wheat growing regions of Turkey, including the Central and South East Anatolia, Black Sea, and Aegean. Crown and stem base pieces from bread wheat (Triticum aestivum L.) and durum wheat (Triticum durum Desf.) showing symptoms of discoloration were surface disinfested in 1% sodium hypochlorite solution for 3 min., rinsed three times in sterile distilled water, dried on sterile filter paper, and cultured on peptone PCNB agar (Leslie and Summerell, 2006). Growing colonies were transferred to Synthetischer Nährstoffarmer Agar (Leslie and Summerell, 2006) for sporulation. Single spores were isolated in sterile distilled water and transferred to water agar for single spore isolation. Monosporic cultures were identified as Fusarium redolens Wollenw. by morphology (Leslie and Summerell, 2006) and by sequencing the translation elongation factor -1 alpha (TEF-1α) gene region using ef1 (5’- ATGGGTAAGGARGACAAGAC-3’) and ef2 (5’-GGARGTACCAGTSATCATG-3’) primers (O’Donnell et al. 1998). BLAST analysis with the NCBI GenBank database was performed on the TEF gene sequences (approximately 650 bp) for all isolates. Nineteen isolates resulted in matches of 99% and 100% respectively to the F. redolens accessions GU250584 and HQ731063. These isolates were tested for pathogenicity on the susceptible durum wheat variety (Kiziltan). Plastic tubes (2.5 cm in diam X 16 cm in height) were filled with a mixture of sterile sand, soil, and peat (50:40:10, v:v). A PDA plug (1-cm diam.) was taken from the margin of a 7-day-old culture and placed in the tube. A single pre-germinated seed was placed on the PDA plug and covered with planting medium. A sterile agar plug was used as a non-inoculated control. Each treatment (isolates and control) had three replicates, and the experiment was repeated to confirm the results. Nine weeks after inoculation, plants were washed and checked for disease symptoms on both the crown and the stem base. Rating for disease severity was performed using a 1-5 scale (1: 1-9%, 2: 10-29%, 3: 30-69%, 4: 70- 89%, 5: 90-99%) modified from Wildermuth and McNamara (1994) and results were analysed with ANOVA. Disease ratings ranged from 1 to 3 with an average of 1.7. Three of the isolates caused ratings significantly greater than the control (avg=3,3 and 2.7). Necrosis and brown discoloration was observed on the lower stems of these treated plants, while control treatments showed no symptoms. Fungi were re-isolated from crowns of inoculated plants and control plants and confirmed to be F. redolens based on morphology. Fusarium redolens has been reported to cause crown rot on durum wheat in Saskatchewan, Canada (Taheri et al. 2011), Fusarium yellows on chickpea (Cicer arietinum L.) in Spain (JimenezFernandez et al. 2011), and rot of onions (Allium cepa L.) in Turkey. This report confirms F. redolens as causal agent of crown rot of wheat in Turkey.

Exploring the supply and demand factors of varietal turnover in Indian wheat

Posted by gabrielamartinez on , in Journal Articles

56868Authors: Krishna, V.V.; Spielman, D.J.; Veettil, P.C.

Published in: Journal of Agricultural Science, 2015.


 

Cultivar depreciation – the gradual decline in relative advantage of a cultivated variety over time – accentuates the vulnerability of resource-poor farmers to production risks. The current paper addresses constraints in combating cultivar depreciation of wheat in India. National level data on quoted demand for breeder seeds and breeder seed production indicated a slowdown in the rate of cultivar turnover of wheat, with average varietal age increasing from 9 years in 1997 to 12 years in 2009. Analysis of cultivar adoption patterns among farmer households of Haryana State also indicates that farmers prefer cultivars that were released a decade ago over the recent ones.

Cultivar turnover rates are found to be particularly low among marginal farmers. While the structure of India’s wheat breeding and seed delivery systems might be the primary cause of slow cultivar turnover, a number of social and economic factors at the micro-level are also responsible. Many of the constraints to technology adoption and wheat productivity growth, identified during the Green Revolution era, persist even today.

Options for increasing the productivity of the rice–wheat system of north-west India while reducing groundwater depletion : Part 1. Rice variety duration, sowing date and inclusion of mungbean

Posted by gabrielamartinez on , in Journal Articles

56831

Authors: Singh, B. ; Humphreys, E.; Yadav, S.; Gaydon, D.S.

Published in: Field Crops Research, 173: 68–80, 2015.


 

The irrigated rice–wheat (RW) systems of north-west India are critical for food security. However, these systems are not sustainable due to over-exploitation of the groundwater resource on which they largelyrely. Current farmer practice (FP) involves manual transplanting of rice into heavily tilled/puddled soil from 10 June to early July, prolonged periods of flooding, rice residue burning, and heavy tillage prior to sowing wheat. Inclusion of a short duration mungbean crop between wheat harvest and rice transplanting has also been promoted at times. Options for reducing irrigation input to the RW system include delaying transplanting until after the monsoon rains start (late June), switching to shorter duration rice varieties, and alternate wetting drying (AWD) water management for rice. However, the effect of such practices on groundwater depletion is not well-understood. Examining the effects of these options on cropping system yield and components of the water balance and water productivity is highly complex because of the need to consider the interactions between each crop in the system. Therefore, we used a cropping system model (APSIM) to compare the performance of RW systems with a range of rice transplanting dates (4 dates from 10 June to 10 August) and rice variety durations (long – 158 d, medium – 144 d, short – 125 d), with and without mungbean in the system. The results suggest that changing from long to short duration varieties would reduce ET by around 250 mm, more than enough to halt the groundwater decline, but with a reduction in rice-equivalent system yield of about 2.5 t ha−1 compared with current FP.
On the other hand, inclusion of mungbean into the RW system results in much higher system yield than recommended farmer practice (by over 3 t ha−1), but the tradeoffs are much higher ET (by 250–300 mm) and irrigation requirement (by 300–450 mm). The results of this study suggest that more effort should be directed towards the development of higher-yielding, short duration rice varieties to reduce groundwater depletion of the RW system while maintaining yield, and that inclusion of short duration summer crops such as mungbean should not be recommended.

Evaluation of advance wheat lines for agronomic traits in rainfed environment

Posted by Carelia Juarez on , in Journal Articles

Published in Pakistan Journal Agricultural Research 27 (279-88, 2014.

Sohail, M.; Hussain, I.; Din, R.;Tanveer, S.K.; Qamar, M.; Abbas, S.H.

Wheat under rainfed conditions of Pothwar region of Pakistan is usually exposed to limited soil moisture during early growth period and high temperature stress during reproductive growth stage. Better yield under stressful environment is the main objective while evaluating genotypes for rainfed ecologies. A field study was conducted at National Agricultural Research Centre (NARC), Islamabad, Pakistan to evaluate the agronomic traits of three advance lines (NR-397, NR-379 and NR-400) in comparison to released variety (NARC-09) under rainfed conditions during crop season 2010-2011. Crop was sown on normal (November 15) and late (December 15) planting times to create variable growing conditions especially during reproductive growth period. The adverse effect of the late planting was significant (P<0.05) on grain yield of the crop. Late planting produced 29% lower grain yield than normal planting. Genotypes also showed significant variation (P<0.05) regarding grain yield production under both normal and late sowing dates. Under more stressful growing conditions (late planting), minimum grain yield reduction was noticed in line NR-397 (19%) followed by NARC-09 (20%), NR-400 (30%) and NR-379 (35%). Late planting conditions also signi- -2 ficantly reduced days to maturity, spikes m and 1000-grain weight in all genotypes as compared to normal sowing; however, the reduction in these parameters were significantly less (P<0.05) in wheat lines NR-397 and NARC-09 as compared to other two genotypes. Results showed that comparatively higher grain yields of lines NR-397 and NARC-09 were correlated to their better leaf chlorophyll retention and maintenance of low canopy temperature during grain filling periods particularly under late planting conditions. Findings of this study have indications that wheat sowing up to November 15 is more appropriate time and advance lines NR- 397 and NARC-09 have the genetic potential to tolerate adverse rainfed growing conditions under agro-ecological conditions of Pothwar region, Pakistan.

Physio-agronomic traits evaluation of wheat genotypes for Adaptability under rainfed conditions

Posted by Carelia Juarez on , in Journal Articles

Published in Sarhad Journal AGriculture 30 (2151-156, 2014.

Sohail, M.;Hussain, I.; Din, R.; Tanveer, S.K.; Qamar, M.; Abbas, S.H.

High temperature stress during grain filling stages is one of the main wheat yield limiting factors under rainfed conditions of Pakistan. A field experiment was carried out to evaluate physio-agronomic traits of different wheat genotypes for better yield and heat tolerance under rainfed conditions. Variable growing conditions during grain filling period were created by sowing crop on normal (November 15) and late sowing dates (December 15). Crop planted on normal sowing date had significant affect (p<0.05) and produced 29% higher grain yield as compared to late planting. Significant variation (p<0.05) was also noticed among genotypes in terms of physiological and agronomic traits under both under both normal and late sowing dates, as advance line NR-397 and NARC-09 produced significantly higher (p<0.05) grain yields as compared to NR-400 and NR-379. Higher grain yields of these two cultivars were associated with their more number of days to maturity, higher spikes m2 and heavier grains as compared to other two genotypes. At the same time, grain yields of wheat genotypes showed a strong correlation to their leaf chlorophyll (+0.98) and canopy temperature (-0.99) measurements. Higher grain yields of NR-397 and NARC-09 were directly correlated to the

Grain yield of newly developed wheat cultivar (NARC 201) as enhanced by foliar application of humic acid under rainfed conditions

Posted by Carelia Juarez on , in Journal Articles

Published in Sarhad Journal Agriculture 30 (2173-178, 2014.

Abbas, S.H.; Sohail, M.; Hussain, I.; Saleem, M.; Qamar, M.; Aslam, M.; Imram, M.

A newly developed wheat cultivar NARC 2011 was evaluated for physio- agronomic traits by varying Humic acid concentrations and Effective microbes at different phenological stages during rabi season of 2010-11 in the field area allocated to national coordinated wheat program of national agricultural research centre, Islamabad. The experiment was laid out using randomized complete block design (RCBD) for an assortment of growth and yield characters at various Humic acid concentrations and Effective microbe under rainfed conditions. There were six treatments and were replicated three times. Results revealed that E.M enhanced sub stomatal CO2 concentration in the flag leaf of mother shoot significantly, whereas for transpiration rate, spike length, number of spikelets spike-1 , flag leaf area and thousand seed weight, its effect but statistically at par. The highest grain yield of 3566 kg ha-1 was achieved at N P (115:85 kg ha- 1) in combination with 3000 mL ha-1 concentration of humic acid at tillering +flag leaf initiation +grain filling stages hence resulting in 30 percent greater yield than control (2747 kg ha-1). Similarly the highest biological yield of 12667 kg ha-1 was achieved at same level of NP in combination with 3000 mL ha-1 concentration of humic acid at tillering +flag leaf initiation +grain filling stages hence resulting in 31 percent greater biological yield than control (9667 kg ha-1). Hence in order to achieve higher biological and grain yield in rainfed regime, humic acid along with optimum recommended area specific NP levels depending up on soil nutritional status may be applied at appropriate phenological stages of wheat crop.

Overview and Application of QTL for Adult Plant Resistance to Leaf Rust and Powdery Mildew in Wheat

Posted by Carelia Juarez on , in Journal Articles

Published in Crop Science 54 (51907-1925, 2014

Zaifeng Li;Caixia Lan; He Zhonghu; Singh, R.P.; Rosewarne, G.M.; Xinmin Chen; Xianchun Xia

Leaf rust and powdery mildew, caused by Puccinia triticina and Blumeria graminis f. sp. tritici, respectively, are widespread fungal diseases of wheat (Triticum aestivum L.). Development of cultivars with durable resistance is crucially important for global wheat production. This paper reviews the progress of genetic study and application of adult plant resistance (APR) to wheat leaf rust and powdery mildew. Eighty leaf rust and 119 powdery mildew APR quantitative trait loci (QTL) have been reported on 16 and 21 chromosomes, respectively, in over 50 publications during the last 15 yr. More important, we found 11 loci located on chromosomes 1BS, 1BL, 2AL, 2BS (2), 2DL, 4DL, 5BL, 6AL, 7BL, and 7DS showing pleiotropic effects on resistance to leaf rust, stripe rust, and powdery mildew. Among these, QTL on chromosomes 1BL, 4DL, and 7DS also correlate with leaf tip necrosis. Fine mapping and cloning of these QTL will be achieved with the advent of cheaper high-throughput genotyping technologies. Germplasm carrying these potential resistance genes will be useful for developing cultivars with durable multidisease resistance. In addition to its non-NBS–LRR (nucleotide binding site–leucine rich repeat) structure, the senescence-like processes induced by Lr34 could be the reason for durability of resistance; however, more information is needed for a full understanding of the molecular mechanism related to durability. Adult plant resistance genes have been used by CIMMYT for more than 30 yr and have also been transferred to many Chinese wheat varieties through shuttle breeding.

Dayaniklilik Geni Cre1’ in Akdeniz Tahil Kist Nematodu, Heterodea latipons Franklin (Tylenchida: Heteroderidae)’e Karsi Etkinliginin Arastirilmasi

Posted by Carelia Juarez on , in Journal Articles

Published in Journal of Agricultural Science 20  261-268, 2014

Imren, M.; Kasapoglu, E.B.; Dababat, A.A.; Toktay, H.;Elekcioglu, I.H.

Cereal cyst nematodes (Heterodera avenae group) are important pests of wheat; they include the three most important species of cereal cyst nematodes: Heterodera avenae Wollenweber, H. latipons Franklin and H. filipjevi (Madzhidov) in Turkey that were determined in different wheat growing areas. It was reported that Mediterranean cereal cyst nematode, Heterodera latipons which is widely found in the centre of the durum wheat growing area -South-eastern Anatolia regionin our country was reaching the economical threshold in many locations. It is known that the use of resistant/tolerant wheat varieties is the most effective controlling method against cyst nematodes in the wheat cultivation. Nowadays, nine different resistance genes (Cre genes), which are transferred from wild wheat species to wheat cultivated forms are available. In this study, the efficiency of the resistance gene, Cre1, against the population of H. latipons from Gaziantep (Karkamıs) was investigated. In the study, 38 genotypes carrying Cre1 gene and 26 genomes lacking resistance genes; this gives a total 64 wheat genotypes which are produced by parental crossing of SILVERSTAR containing the resistance gene, Cre1, in its genome, SOKOLL, CALINGIRI, GOLDMARKER, CROC_1/AE.SQUARROSA(224)//OPATA,FRAME, STYLET and PASTOR were used against H. latipons in the experiment. Among the 64 genotypes; 20 were resistant, 32 were moderately resistant and 12 were moderately susceptible to the nematode. Ten resistant, 20 moderately resistant and 8 moderately susceptible lines were determined against H. latipons that these 38 lines carried the Cre1 gene in their genome. Within this study, the resistant gene, Cre1, was not found to be completely resistant against H. latipons, but its 78% efficiency rate was found to be successful: therefore, it was concluded that it can be used against H. latipons in national wheat breeding programs. Furthermore, PASTOR, SOKOLL and CROC_1/AE.SQUARROSA(224)//OPATA wheat genotypes were determined as good resistance source against H. latipons.