Browsing by Author "B. Arun"

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A wheat phenotyping network to incorporate physiological traits for climate change in South Asia
(Elsevier B.V., 2014) Alistair Pask; A.K. Joshi; Y. Manès; I. Sharma; R. Chatrath; G.P. Singh; V.S. Sohu; G.S. Mavi; V.S.P. Sakuru; I.K. Kalappanavar; V.K.Mishra; B. Arun; M.Y. Mujahid; M. Hussain; N.R. Gautam; N.C.D. Barma; A. Hakim; W. Hoppitt; R. Trethowan; M.P. Reynolds
South Asia, which is already home to more than one fifth of the world's population and rapidly growing, will require wheat yields to rise annually by 2.0 to 2.5% to meet demand and maintain food security. To address these challenges, a wheat phenotyping network was established in the region in 2009 to support national breeding programs by applying practical phenotyping techniques to increase selection success using a cooperative multi-location testing network. A number of trials have been grown to introduce new genetic diversity for stress adaptive traits, to establish their genetic bases, and to test a new generation of lines developed using physiological approaches. The 17th Semi-Arid Wheat Yield Trial (SAWYT), consisting of a group of 50 elite spring bread wheat advanced lines, bred in Mexico using both conventional (CON) and physiological trait (PT) approaches, was grown for two seasons 2009/10 and 2010/11. Data showed that PT lines gave superior yields overall, associated with higher grain weight, and with cooler vegetative and grain-filling canopy temperatures (CT); the CT trait is considered indicative of increased gas exchange, a likely consequence in these environments of superior vascular capacity including deeper rooting to access subsoil water. Local check genotypes, which were generally well adapted to the stressed environments tended to be 3-5 days earlier to heading than CIMMYT cultivars. Results demonstrate the potential to integrate physiological breeding approaches into genetic improvement for the region, particularly as future wheat production will take place under increasing water scarcity. © 2014 Elsevier B.V..
Breeding crops for reduced-tillage management in the intensive, rice-wheat systems of South Asia
(2007) A.K. Joshi; R. Chand; B. Arun; R.P. Singh; Rodomiro Ortiz
The importance of reduced tillage in sustainable agriculture is well recognized. Reduced-tillage practices (which may or may not involve retention of crop residues) and their effects differ from those of conventional tillage in several ways: soil physical properties; shifts in host-weed competition; soil moisture availability (especially when sowing deeply or under stubble); and the emergence of pathogen populations that survive on crop residues. There may be a need for genotypes suited to special forms of mechanization (e.g. direct seeding into residues) and to agronomic conditions such as allelopathy, as well as specific issues relating to problem soils. This article examines issues and breeding targets for researchers who seek to improve crops for reduced-tillage systems. Most of the examples used pertain to wheat, but we also refer to other crops. Our primary claim is that new breeding initiatives are needed to introgress favourable traits into wheat and other crops in areas where reduced or zero-tillage is being adopted. Key traits include faster emergence, faster decomposition, and the ability to germinate when deep seeded (so that crops compete with weeds and use available moisture more efficiently). Enhancement of resistance to new pathogens and insect pests surviving on crop residues must also be given attention. In addition to focusing on new traits, breeders need to assess germplasm and breeding populations under reduced tillage. Farmer participatory approaches can also enhance the effectiveness of cultivar development and selection in environments where farmers' links with technology providers are weak. Finally, modern breeding tools may also play a substantial role in future efforts to develop adapted crop genotypes for reduced tillage. © 2006 Springer Science+Business Media B.V.
Comparative evaluation of exotic and adapted germplasm of spring wheat for floral characteristics in the Indo-Gangetic Plains of northern India
(2007) S.K. Singh; B. Arun; A.K. Joshi
Four hundred spring wheat genotypes, comprising exotic and indigenous germplasm and adapted cultivars for commercial cultivation, were investigated during four crop seasons for six floral characteristics related to outcrossing behaviour. Genetic variability and heritability were investigated along with phenotypic correlation coefficients among these characteristics. A significant quantitative variation existed among the characteristics in all three groups. High heritability for stigma length, openness of florets, anther extrusion and duration of floral opening indicated that selection for these characteristics may be effective. The adapted cultivars were found more promising than the exotic and indigenous germplasm. Most of the characteristics showed significantly positive correlation with each other and high correlation was observed between anther and stigma length, and anther extrusion and duration of floral opening. Superiority of varietal mixtures and segregating generations (F3 and F4) of two crosses over parental lines suggested that heterozygosity and heterogeneity can provide yield advantages. Germplasm lines possessing superior expression of floral characteristics may be used to improve yielding ability through enhanced heterozygosity or the development of hybrids. © 2007 The Authors.
Development of somaclonal variants of wheat (Triticum aestivum L.) for yield traits and disease resistance suitable for heat stressed and zero-till conditions
(2007) B. Arun; B.D. Singh; S. Sharma; R. Paliwal; A.K. Joshi
In a substantial rice-wheat cropping system area of South Asia, wheat sowing often gets too delayed and exposed to terminal heat stress. Therefore, farmers prefer varieties that are able to perform well under a short growing period. Tissue culturally regenerated plants of wheat variety cv. HUW 234, the most widely cultivated variety of North Eastern Plain Zone (NEPZ) of India were screened using immature embryo as explant. Days to heading and maturity, yield and other yield components and resistance to leaf rust and spot blotch were evaluated. A few somaclones in R3 and R4 generations displayed significant earliness for days to heading and maturity, improved yield traits and resistance to leaf rust and spot blotch diseases. The superior performance of two of the variants was confirmed in the R5 generation in 3 years of testing under two dates of conventional and zero-till sowing. Stability analysis also suggested superiority of the two somaclones across 12 environments. This appeared to confirm the possibility of obtaining useful somaclonal variants of wheat for very late sown as well as zero-till managed agriculture. The superior performing somaclones can be used as parents in the ongoing breeding programmes targeting late sown wheat in South Asia exposed to terminal heat stress. © 2007 Elsevier B.V. All rights reserved.
Enhanced resistance in wheat against stem rust achieved by marker assisted backcrossing involving three independent Sr genes
(Elsevier, 2015) Punam S. Yadav; V.K. Mishra; B. Arun; R. Chand; M.K. Vishwakarma; N.K. Vasistha; A.N. Mishra; I.K. Kalappanavar; Arun K. Joshi
Marker assisted backcrossing (MABC) was used to transfer the three stem rust (Puccinia graminis tritici) resistant genes Sr25, SrWeb and Sr50 into the popular Indian wheat cv. HUW234. The donor was the CIMMYT breeding line PMBWIR4, and each of the target genes was marked by a simple PCR assay. A three step screening strategy was adopted: the first screen comprised foreground selection, the second used markers lying close to the introgression borders to reduce the extent of linkage drag, and the last was background selection based on 149 informative microsatellite assays. Based on the background selection outcomes, at the BC1F1 generation the proportion of the genome fixed for cv. HUW234 alleles ranged from 55% to 67%. Three BC1F1 individuals were crossed a second time with cv. HUW234, resulting in the identification of six BC2F3 families carrying all three target Sr genes; the proportion of their genome inherited from cv. HUW234 ranged from 86% to 92%. BC2F4 and BC2F5 material was planted at three different locations under both disease-free and artificially induced epiphytotic conditions. Compared to recurrent parent, the improved versions of cv. HUW234 displayed significantly superior resistance to stem rust, and their agronomic performance was as good as, or even marginally better than that of the source cultivar. © 2015.
Exploring the possibility of obtaining terminal heat tolerance in a doubled haploid population of spring wheat (Triticum aestivum L.) in the eastern Gangetic plains of India
(2012) Chhavi Tiwari; Hugh Wallwork; Ram Dhari; B. Arun; V.K. Mishra; Arun K. Joshi
High temperature during grain filling stage causes significant yield losses to wheat in south Asia and many other parts of the world. One hundred and forty doubled haploid (DH) wheat lines (including parents), derived from the cross Berkut (heat susceptible) × Krichauff (heat tolerant), were grown in six environments comprising two dates of sowing in three consecutive years (2007-2008, 2008-2009, and 2009-2010) at Banaras Hindu University, Varanasi, India. The objective was to assess DH lines for heat tolerance and to identify superior lines under hot humid environments of the eastern Gangetic plains (EGP) of India. Considerable variation was observed for grain yield (GY), thousand grain weight (TGW), grain fill duration (GFD), and canopy temperature (CT). Likewise, considerable variation was also observed for heat susceptibility index (HSI) of GY, TGW, and GFD. The DH lines were grouped into four categories based on the HSI and around 5-10% lines were categorized as heat tolerant. A few lines yielded significantly more than the better parent and possessed good expression of other traits. The most promising 20 lines have been listed as sources of heat tolerance, with 3 lines better yielding than the superior parent Krichauff. The results demonstrated that it is possible to obtain lines that perform better for yield and yield related traits in heat stressed environments of the EGP of India. © 2012 Elsevier B.V.
Genetic evaluation of spring wheat (Triticum aestivum l.) recombinant inbred lines for spot blotch (Bipolaris sorokiniana) resistance and yield components under natural conditions for South Asia
(Tarbiat Modares University, 2014) N. Meena; V.K. Mishra; D.K. Baranwal; A.K. Singh; V.P. Rai; R. Prasad; B. Arun; R. Chand
The objectives of the present study were to evaluate spring wheat recombinant inbred lines (RILs) of diverse origin by estimating genetic parameters viz., variability, character association, cluster analysis, and principal component analysis (PCA) for spot blotch resistance and yield components at BHU Agricultural Research Farm during 2010-2011. Grain yield per plot was significantly and positively associated with biomass, 1,000-grain weight, harvest index, chlorophyll content, and grains per spike at genotypic level. The line 65 exhibited lowest mean of AUDPC value (632) indicating its potential as resistant parent. Cluster analysis grouped all the 324 spring wheat lines into 19 clusters using Ward’s method. Extreme divergence was observed among clusters. By using D2-statistics, the highest inter cluster distance (584.72) was found between Clusters VIII and XIX. Cluster VIII recorded highest mean values for chlorophyll content, peduncle length, biomass, grains per spike, 1000-grain weight and grain yield. The major contributing trait towards genetic divergence was found to be AUDPC (60.36%). First 5 principal components (PC1, PC2, PC3, PC4 and PC5) accounted for proportionate values of 20.66, 17.96, 15.07, 8.28, and 7.38%, respectively, contributing 69.35% of the total variability. The second PCs had high positive PC value for plant height, biomass, and 1,000-grain weight. The breeding objectives of the present experiment was to identify genetically diverse wheat spot blotch resistant RILs for developing high yielding spot blotch resistant cultivars especially adopted to south Asia in future breeding programs. ©, Tarbiat Modares University. All rights reserved.
Genotype × environment interaction for zinc and iron concentration of wheat grain in eastern Gangetic plains of India
(2010) A.K. Joshi; J. Crossa; B. Arun; R. Chand; R. Trethowan; M. Vargas; I. Ortiz-Monasterio
Zinc and iron are important micronutrients for human health for which widespread deficiency occurs in many regions of the world including South Asia. Breeding efforts for enriching wheat grains with more zinc and iron are in progress in India, Pakistan and CIMMYT (International Maize and Wheat Improvement Centre). Further knowledge on genotype × environment interaction of these nutrients in the grain is expected to contribute to better understand the magnitude of this interaction and the potential identification of more stable genotypes for this trait. Elite lines from CIMMYT were evaluated in a multilocation trial in the eastern Gangetic plains (EGP) of India to determine genotype × environment (GE) interactions for agronomic and nutrient traits. Agronomic (yield and days to heading) data were available for 14 environments, while zinc and iron concentration of grains for 10 environments. Soil and meteorological data of each of the locations were also used. GE was significant for all the four traits. Locations showed contrasting response to grain iron and zinc. Compared to iron, zinc showed greater variation across locations. Maximum temperature was the major determinant for the four traits. Zinc content in 30-60 cm soil depth was also a significant determinant for grain zinc as well as iron concentration. The results suggest that the GE was substantial for grain iron and zinc and established varieties of eastern Gangetic plains India are not inferior to the CIMMYT germplasm tested. Hence, greater efforts taking care of GE interactions are needed to breed iron and zinc rich wheat lines. © 2010 Elsevier B.V. All rights reserved.
Helminthosporium leaf blight resistance and agronomic performance of wheat genotypes across warm regions of South Asia
(2004) R.C. Sharma; E. Duveiller; F. Ahmed; B. Arun; D. Bhandari; M.R. Bhatta; R. Chand; P.C.P. Chaurasiya; D.B. Gharti; M.H. Hossain; A.K. Joshi; B.N. Mahto; P.K. Malaker; M.A. Reza; M. Rahman; M.A. Samad; M.A. Shaheed; A.B. Siddique; A.K. Singh; K.P. Singh; R.N. Singh; S.P. Singh
Helminthosporium leaf blight (HLB) is the most important disease constraint to wheat (Triticum aestivum L.) cultivation in the eastern Gangetic Plains of South Asia. A Helminthosporium Monitoring Nursery (HMN) including potential adapted and exotic sources of HLB resistance was developed in Bangladesh, India and Nepal to assess the stability of genetic resistance across locations. The 8th, 9th and 10th HMN assessed the HLB resistance and agronomic traits of 17 wheat genotypes across 20 environments of Bangladesh, India and Nepal in the 1999-2000, 2000-2001 and 2001-2002 cropping seasons, respectively. The area under the disease progress curve (AUDPC) for HLB, grain yield, thousand-kernel weight (TKW), days to heading, days to maturity, and plant height were examined. The 17 genotypes showed a range of variability for disease and agronomic characters. Disease severity (AUDPC) differed in the 3 years and showed the highest values in 2002. The increase in AUDPC in 2002 caused the lowest grain yield, with an average 18% reduction due to HLB. A few genotypes (SW 89-5422, Yangmai-6 and Ning 8201) appeared to have stable HLB resistance across environments. However, most of the higher-yielding genotypes, except BL 1883, were unstable. The results suggest that careful selection of HLB resistance with acceptable grain yield, TKW and plant height may be possible using the wheat genotypes included in the HMN.
Inheritance of Terminal Heat Tolerance in Two Spring Wheat Crosses
(Akademiai Kiado ZRt., 2013) R. Paliwal; B. Arun; J.P. Srivastava; A.K. Joshi
The objective of this study was to develop an understanding about the genetics of terminal heat tolerance in wheat (Triticum aestivum L.). The minimum number of genes was assessed using Mendelian and quantitative genetic approach. Two crosses were made between heat tolerant and heat susceptible bread wheat cultivars: NW1014 × HUW468 and HUW234 × HUW468. Heat susceptible HUW468 was common in both the crosses. The F4, F5 and F6 generations were evaluated including F1 in two different dates of sowing (normal and very late) under field conditions in year 2006–07. The data was recorded for grain fill duration (GFD) and thousand-grain weight (TGW). Based on data of two dates, decline% and heat susceptibility index (HSI) of GFD and TGW were estimated. Heat tolerance in F1 showed absence of dominance. Estimation of genes using Mendelian approach in F4, F5 and F6 progenies (148–157) of the two crosses suggested that heat tolerance was governed by a minimum of three genes. Quantitative approach also indicated similar number of genes. The distribution of progeny lines in F4 and F6 supported the polygene nature of heat tolerance. These genes if mapped by molecular approach can play an important role through marker assisted selection (MAS) for developing improved thermo-tolerant lines of wheat. © 2013, Akadémiai Kiadó, Budapest.
Marker-assisted improvement of grain protein content and grain weight in Indian bread wheat
(Springer Netherlands, 2016) Manish K. Vishwakarma; B. Arun; V.K. Mishra; P.S. Yadav; H. Kumar; Arun K. Joshi
The leading Indian wheat cultivar ‘HUW234’ produces grain with relatively low protein content (GPC) and thousand grain weight (TGW). Therefore, marker-assisted backcrossing was used to improve these two important traits by introducing favorable genes/alleles from cv. ‘Glu133’, which harbors both alleles for both GPC (Gpc-B1) and TGW. Foreground selection for GPC was achieved using microsatellite markers Xucw108 linked with Gpc-B1 and Xgwm297 linked with TGW. Background selection applied to support recovery of the recurrent parent genotype was based on 86 genomically distributed microsatellites. A selected BC2F1 plant was the progenitor of 15 BC2F4 families, in which representation of the cv. HUW234 genome ranged from 89.5 to 93.0 %. The new derivatives of HUW234 were comparable in yield to the original cultivar, but with both significantly higher GPC and heavier kernels. © 2015, Springer Science+Business Media Dordrecht.
Molecular mapping of high temperature tolerance in bread wheat adapted to the Eastern Gangetic Plain region of India
(Elsevier B.V., 2013) Chhavi Tiwari; Hugh Wallwork; Uttam Kumar; Ram Dhari; B. Arun; V.K. Mishra; M.P. Reynolds; Arun K. Joshi
The inheritance of tolerance to high temperature stress during the grain filling period was investigated via a QTL analysis based on 138 doubled haploid progeny of a cross between the wheat cultivars Berkut and Krichauff. Performance data were collected from three seasons, in each of which the material was planted both at the conventional time and a month later. A heat sensitivity index (HSI) was also used to monitor the effect of high temperature on grain yield, thousand grain weight, grain filling duration and canopy temperature. Using composite interval mapping, seven stable QTL were identified for HSI of traits, mapping to chromosomes 1D, 6B, 2D and 7A. Three of the QTL related to HSI of grain filling duration, two to thousand grain weight and one each to grain yield and canopy temperature. A region of chromosome 1D harbored a QTL determining HSI of both thousand grain weight and canopy temperature. The QTL analysis for the direct traits GY, TGW, GFD and CT led to detection of 22 QTLs spread over to 17 chromosomal regions. Of these 13 QTLs were shown under normal sown, while 9 under the heat stress. A QTL for TGW on chromosome 6B under normal sown co-located with HSI(TGW) QTL QHTgw.bhu-6BL. QTL. ×. environment interactions were not observed for any of the grain filling duration associated loci. © 2013 Elsevier B.V.
Performance of biofortified spring wheat genotypes in target environments for grain zinc and iron concentrations
(2012) G. Velu; R.P. Singh; J. Huerta-Espino; R.J. Peña; B. Arun; A. Mahendru-Singh; M. Yaqub Mujahid; V.S. Sohu; G.S. Mavi; J. Crossa; G. Alvarado; A.K. Joshi; W.H. Pfeiffer
Genetic biofortification to improve zinc (Zn) and iron (Fe) concentrations in bread wheat (Triticum aestivum L.) could reduce micronutrient malnutrition-related problems in the developing world. A breeding program on wheat was started to enhance Zn and Fe concentrations and other essential traits needed in a successful commercial variety. The first set of advanced lines derived from crosses of high yielding wheats with genetic resources possessing high Zn and Fe such as Triticum spelta, landraces and synthetic wheat based on Triticum dicoccon were tested at nine locations in South Asia and Mexico for Zn and Fe concentration, grain yield and other traits. Analyses of variance across locations revealed significant genotypic, environmental and genotype. ×. environment (G. ×. E) effects for grain Zn and Fe concentrations and grain yield. Variances associated with environmental effects were larger than the genotypic and G. ×. E effects for all three traits, suggesting that environmental effects have relatively greater influence. Although G. ×. E interaction was significant, high heritabilities were observed for Zn and Fe concentrations at individual sites and across environments, reflecting non-crossover type of interaction. This trend was confirmed by the high genetic correlations between locations that showed similar ranking of entries across locations, indicating that it is possible to select the best adapted entries with high Zn and Fe concentration. Pooled data across locations showed increments of 28% and 25% over the checks for Zn and Fe. A considerable number of entries exceeded intermediate to full breeding target Zn concentrations, indicating that it is possible to develop Zn-biofortified varieties with competitive yields and other farmer preferred agronomic traits. The positive and moderately high correlation between Zn and Fe concentration suggest good prospects of simultaneous improvement for both micronutrients. © 2012 Elsevier B.V.
Relationship of plant height and days to maturity with resistance to spot blotch in wheat
(2002) A.K. Joshi; R. Chand; B. Arun
A total of 1,407 spring wheat (T. aestivum) lines of Indian and CIMMYT (International Maize and Wheat Improvement Centre, Mexico) origin were evaluated for plant height, days to maturity and resistance to spot blotch (caused by Bipolaris sorokiniana) during the 1994-95, 1995-96 and 1996-97 crop seasons. The frequency distribution of genotypes, based on disease score ignoring the growth stages, differed from the distribution in which disease score was assessed on a similar growth stage. Two crosses each, between 'tall resistant x dwarf susceptible' and 'late resistant x early susceptible' genotypes, were made. The evaluation of homozygous resistant lines in the F3, F4 and F5 generations of both crosses showed a wide range of plant height and days to maturity. These lines showed significant differences for plant height and days to maturity but did not show a significant difference for AUDPC values of spot blotch. The correlation coefficients for AUDPC versus plant height or days to maturity were weak, i.e., -0.336 and 0.061, respectively. Results indicated that resistance to spot blotch severity was independent of plant height and days to maturity in progenies from these crosses.
Studies on genetic variability, correlation and path analysis for yield and yield contributing traits in wheat (T. Aestivum L. Em Thell.)
(2012) D.K. Baranwal; V.K. Mishra; M.K. Vishwakarma; Punam S. Yadav; B. Arun
A study was undertaken to analyze the genetic variability, correlation and path coefficient analysis of yield and yield contributing traits in twenty four wheat genotypes grown at BHU Agricultural Farm, during Rabi season of 2010-11. Wide genetic variation was observed among genotypes for days to heading, plant height, tillers per m2 and grains per spike. Considering genetic parameters, high genotypic co-efficient of variation (GCV) was observed for grains per spike, peduncle length, plant height whereas, low GCV was observed for days to heading, chlorophyll content and tillers per m2. In all cases, phenotypic variances were higher than the genotypic variances. High heritability with low genetic advance in per cent of mean was observed for days to heading which indicated the involvement of non-additive gene action for the e×pression of this character and selection for such trait might not be rewarding. High heritability with high genetic advance in per cent of mean was observed for peduncle length and grains per spike indicating that these traits were under additive gene control and selection for genetic improvement for these traits would be effective. Yield per plot had high positive and significant correlation with tillers per m2 and 1000-grain weight. Path coefficient analysis revealed ma×imum direct contribution towards yield per plot with sheath length followed by grains per spike.
Validation of molecular markers for stem rust resistance and identification of suitable wheat germplasm targeting Eastern Gangetic plains of India
(Indian Society of Genetics and Plant Breeding, 2015) P.S. Yadav; V.K. Mishra; B. Arun; R. Chand; A.K. Joshi
Five molecular markers were used to identify stem rust resistance genes, namely, Sr2, Sr22, Sr25/Lr19, Sr50 and SrWeb in eight diverse wheat lines from CIMMYT, Mexico and India that included three popular cultivars of north eastern Gangetic plains of India. One of the CIMMYT line, PMWBIR4 carried all the above mentioned five Sr genes, while other lines showed different combinations. The identified wheat genotypes may be useful in stem rust resistance breeding. Validation of linked markers for rust resistance suggested that the markers can be deployed in marker assisted molecular breeding program. © 2015, Indian Society of Genetics and Plant Breeding. All rights reserved.
Wheat somaclonal variants showing earliness, improved spot blotch resistance and higher yield
(2003) B. Arun; A.K. Joshi; R. Chand; B.D. Singh
Somaclones (R2, R3 and R4 generations) were regenerated from immature embryos of two spring wheat varieties, HUW-206 and HUW-234. Many somaclones displayed improved earliness, enhanced resistance to spot blotch disease and increased yield over the parent. The superiority of variants for yield traits and disease resistance was established in R 4 generation, confirming the possibility of wheat improvement through somaclonal variation.