Browsing by Author "R. Chatrath"

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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..
Challenges to wheat production in South Asia
(2007) R. Chatrath; B. Mishra; G. Ortiz Ferrara; S.K. Singh; A.K. Joshi
Wheat is the second major staple crop, after rice, in India and Pakistan and is also gaining similar importance in Nepal and Bangladesh. Wheat production in South Asia has increased from 15 mt in 1960s to 95.5 mt during 2004-2005. It still needs to grow at the rate of 2-2.5% annually until the middle of 21st century. However, for India, recent estimations have shown a growth requirement of about 1.1%. Although the wheat improvement programs in these countries, with the active collaboration of national agricultural research centers (NARS) and CIMMYT, has made a significant progress, it is a matter of significant concern that wheat production has stagnated for last few years. Since there is little scope for increasing land area under wheat, the major challenge will be to break the yield barrier by pragmatic genetic and developmental approaches. The most serious constraints to wheat production in this region are a host of biotic and abiotic stresses. Although India has not faced any rust epidemic in the last decade, rusts continue to occupy the place of most dangerous pathogen for the region. Among the abiotic stresses, unusual warming trends during grain filling period are causing yield declines, especially in eastern and central India. There are other challenges that are specific to the highly productive rice-wheat cropping system predominant in the Indo-Gangetic plains. The total factor productivity of this system is declining due to depletion of soil organic carbon. Addition of organic matter to soil through green manuring and crop residue recycling, balanced fertilization, integrated nutrient management, diversification of rice-wheat system are some of the possible remedial measures to improve total factor productivity. The international linkages with CIMMYT needs to be strengthened more closely for developing more productive wheat genotypes and thus, achieving wheat targets in the South Asian region. © 2007 Springer Science+Business Media B.V.
Comparative assessment of food-fodder traits in a wide range of wheat germplasm for diverse biophysical target domains in South Asia
(Elsevier B.V., 2019) M. Blümmel; S.R. Updahyay; N. Gautam; N.C.D. Barma; M. Abdul Hakim; Makhdoom Hussain; Muhammad Yaqub Mujahid; R. Chatrath; V.S. Sohu; G. Mavi; V.K. Mishra; I.K. Kalappanavar; Rudra Naik; Suma Biradar; S.V.S. Prasad; Ravi P. Singh; A.K. Joshi
The paper compares food and straw fodder traits in wheat lines of 6 different CIMMYT wheat trials tested across 32 environments of South Asia (India, Nepal, Bangladesh and Pakistan). Experiments were conducted in the main spring wheat season with sowing time of mid-November to mid-December and harvest between March to April. Investigated and compared were grain yield (GY), straw yield (SY), straw nitrogen (N) content, neutral (NDF) and acid (ADF) detergent fiber, acid detergent lignin (ADL), and in vitro organic matter digestibility (IVOMD). Highly significant (P < 0.0001) differences were observed between cultivar types for all traits. The proportional ranges in traits between the cultivar types were high for GY and SY (>60%), considerable (45%) for HI and straw N (40%), moderate for ADL (18%), and minor for NDF, ADF, and IVOMD (<10%). Across cultivar types GY and SY were significantly positive correlated but GY accounted for only 14% of the variation in SY. Positive fodder traits such as N and IVOMD tended to be negatively associated with GY, whereas negative traits such as NDF, ADF and ADL were positively associated with GY, significantly so (P < 0.05) in the cases of ADF and ADL. Except for one case, broad sense h 2 were stronger for GY than for SY. Among straw fodder quality traits, the negative fodder quality traits ADF showed the highest h 2 for all quality traits, with the exception of the two drought trials. Across all cultivar types only ADF was significantly (P < 0.05) positively related to GY. No significant (P > 0.05) relationships were observed between N, ADF and IVOMD and SY. Among cultivars consistent relationships were only observed between N and GY which were significantly (P = 0.03 to 0.009) inversely correlated in five out of the six cultivar types. Within cultivars types ADF varied by at least 2.3% units in HTNM and 1st DRYT and up to 4.9% units in ESWYT. By extrapolation such cultivar-dependent differences will matter at wheat straw trading. © 2019
Earliness in wheat: A key to adaptation under terminal and continual high temperature stress in South Asia
(2013) S. Mondal; R.P. Singh; J. Crossa; J. Huerta-Espino; I. Sharma; R. Chatrath; G.P. Singh; V.S. Sohu; G.S. Mavi; V.S.P. Sukaru; I.K. Kalappanavarg; V.K. Mishra; M. Hussain; N.R. Gautam; J. Uddin; N.C.D. Barma; A. Hakim; A.K. Joshi
High temperatures are a primary concern for wheat production in South Asia. A trial was conducted to evaluate the grain yield performance of high yielding, early maturing heat tolerant CIMMYT wheat lines, developed recently in Mexico for adaptation to high temperature stresses in South Asia. The trial, comprised of 28 entries and two checks, was grown in 13 locations across South Asia and two environments in Mexico. Each location was classified by mega environment (ME); ME1 being the temperate irrigated locations with terminal high temperature stress, and ME5 as warm, tropical, irrigated locations. Grain yield (GY), thousand kernel weight (TKW), days to heading (DH) and plant height (PH) were recorded at each location. Canopy temperature (CT) was also measured at some locations. Significant differences were observed between ME for DH, PH, GY, and TKW. The cooler ME1 locations had a mean DH of 83 days, compared to 68 days mean DH in ME5. The ME1 locations had higher mean GY of 5.26 t/ha and TKW of 41.8. g compared to 3.63 t/ha and 37.4. g, respectively, for ME5. Early heading entries (<79 days, mean DH) performed better across all locations, with GY of 2-11% above the local checks and 40-44. g TKW. Across all locations the top five highest yielding entries had 5-11% higher GY than the local checks. The early maturing CIMMYT check 'Baj' also performed well across all locations. In the Mexico location, CT was associated with GY, thereby suggesting that cooler canopies may contribute to higher GY under normal as well as high temperature stress conditions. Our results suggest that the early maturing, high yielding, and heat tolerant wheat lines developed in Mexico can adapt to the diverse heat stressed areas of South Asia. © 2013 Elsevier B.V.
Partnering with farmers to accelerate adoption of new technologies in South Asia to improve wheat productivity
(2007) G. Ortiz-Ferrara; A.K. Joshi; R. Chand; M.R. Bhatta; A. Mudwari; D.B. Thapa; M.A. Sufian; T.P. Saikia; R. Chatrath; J.R. Witcombe; D.S. Virk; R.C. Sharma
There are many socioeconomic and technological constraints that affect the production of wheat and other staple cereals in South Asia. Wheat production is one of the economic mainstays in South Asia, but the yield gap between farmers' fields and experimental yields is wide across the region. For the last 3 years, CIMMYT and the CAZS-NR have been collaborating with farmers, NARS, and other South Asian partners to promote improved wheat varieties and new resource conservation technologies (RCTs) in farmers' fields. Participation fostered among farmers, scientists, extension specialists, NGOs and the private sector included variety selection (PVS), and evaluation of agronomic practices. Through PVS, several farmer-preferred technologies have been identified including wheat varieties for adverse conditions in eastern Uttar Pradesh (India) and for boron deficiency in parts of Nepal. There has been considerable improvement in the access of farmers to new varieties and technologies in the rural areas. Yield increases (15-70%) have been achieved by resource-poor farmers over the existing varieties through the adoption of new varieties and RCTs. The farmers have also made substantial cost savings and achieved higher yields through resource-conserving agronomic techniques such as zero till. Seed of the new farmer-selected cultivars has been multiplied by groups of collaborating farmers and widely distributed. © 2007 Springer Science+Business Media B.V.
Variations in straw fodder quality and grain–Straw relationships in a mapping population of 287 diverse spring wheat lines
(Elsevier B.V., 2019) Arun K. Joshi; Uttam Kumar; V.K. Mishra; Ramesh Chand; R. Chatrath; Rudra Naik; Suma Biradar; Ravi P. Singh; Neeraj Budhlakoti; Ravi Devulapalli; Michael Blümmel
A wheat association mapping population consisting of 287 diverse spring wheat lines were evaluated for three years in one location (Varanasi) and out of these for one year across three locations (Karnal, Dharwad and Varanasi) in India. Straw fodder quality traits analyzed were nitrogen (N) content, neutral (NDF) and acid (ADF) detergent fiber, acid detergent lignin (ADL), ash (ASH), in vitro organic matter digestibility (IVOMD) and metabolizable energy (ME) content. Grain yield (GY) and straw yield (SY) were also recorded. Highly significant (P < 0.0001) differences among lines were observed for all traits except for ADF and ADL in the three years trials conducted at Varanasi. However, year and location had strong (P < 0.0001) effects on all traits. Compared to line-dependent variations in GY and SY variation in straw fodder quality traits were small. Proportionally greatest variations between lines were observed for straw N where lowest and highest N varied by about 30%. Difference for NDF and ADF between lines were at most 4% units and below 3% units for IVOMD. Grain yield and straw yield were positively correlated (P < 0.0001) with GY accounting for 26% of the variation in SY. Straw N, IVOMD and ME were weakly but significantly (P < 0.05) negatively associated with GY and SY. Straw NDF and ADF were significantly (P < 0.05) positively correlated with GY but the association was again weak. Straw NDF, ADF and ADL were also weakly but significantly positively correlated with SY. Genome-wide association studies (GWAS) were applied to detect significant marker- straw fodder quality trait associations. Five genomic regions contributed for six traits (ADF, ADL, ASH, IVOMD, ME and NDF). ADF and ADL mapped in the common QTL region on chromosome 2B. Similarly, for the IVOMD and ME QTLs on chromosome 5B were associated with SNP marker, wsnp_Ku_c35090_44349517. While some associations were detected for ADF, ALD, ASH, IVOMD, ME and NDF on chromosomes 1A, 2B, 3A, 5A and 5B, the phenotypic variation explained was low to medium by individual QTL. A likely contributing factor was the comparatively small difference in straw fodder quality traits among the lines. It is interesting to note that line dependent variations in GY and SY were about two-fold. In other words, strong genotypic variations of GY and SY do exist. The lack of any similar variations in straw fodder quality traits is intriguing and requires further research. © 2019 The Authors
Wheat improvement in India: Present status, emerging challenges and future prospects
(2007) A.K. Joshi; B. Mishra; R. Chatrath; G. Ortiz Ferrara; Ravi P. Singh
India is the second largest producer of wheat in the world, with production hovering around 68-75 million tons for past few years. The latest estimated demand for wheat production for the year 2020 is approximately 87.5 million tons, or about 13 million tons more than the record production of 75 million tons harvested in crop season 1999-2000. Since 2000, India has struggled to match that record production figure and thus faces a critical challenge in maintaining food security in the face of its growing population. The current major challenges facing future wheat production in India are increasing heat stress; dwindling water supplies for irrigation; a growing threat of new virulence of diseases such as wheat rusts (yellow, brown, and black) and leaf blight; continuous adoption of rice-wheat systems on around 11 million hectares; changes in urbanization patterns, and demand for better quality wheat. In addition, the threat posed by the new stem rust race Ug99 can not be underestimated. The wide gap (around 2.5 t/ha) between the potential and harvested yield in the eastern Gangetic Plains also cries out for solutions. Addressing issues related to different stresses will require harnessing genes discovered in landraces and wild relatives following conventional as well as non-conventional approaches. For effective technology delivery in areas that suffer from poor linkages with farmers, participatory research needs to be strengthened. The future germplasm requirements from a dependable collaborator such as CIMMYT are largely being dictated by the above factors. © 2007 Springer Science+Business Media B.V.