A.K. Joshi

International Maize and Wheat Improvement Center, Tezcoco, México, Mexico

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Publications (66)72.76 Total impact

  • [Show abstract] [Hide abstract] ABSTRACT: Maintaining wheat productivity under the increasing temperatures in South Asia is a challenge. We focused on developing early maturing wheat lines as an adaptive mechanism in regions suffering from terminal heat stress and those areas that require wheat adapted to shorter cycles under continual high temperature stress. We evaluated the grain yield performance of early-maturing heat-tolerant germplasm developed by CIMMYT, Mexico at diverse locations in South Asia from 2009 to 2014 and estimated the breeding progress for high-yielding and early-maturing heat-tolerant germplasm in South Asia. Each year the trial comprised of 28 new entries, one CIMMYT check (Baj) and a local check variety. Locations were classified by mega environment (ME); ME1 being the temperate irrigated locations with terminal high temperature stress, and ME5 as hot, sub-tropical, irrigated locations. Grain yield (GY), days to heading (DTH) and plant height (PH) were recorded at each location. Effect of temperature on GY was observed in both ME1 and ME5. Across years, mean minimum temperatures in ME1 and mean maximum temperatures in ME5 during grain filling had significant negative association with GY. The ME1 locations were cooler that those in ME5 in the 5 years of evaluations and had a 1–2t/ha higher GY. A mean reduction of 20days for DTH and 20cm in PH was observed in ME5. Negative genetic correlations of −0.43 to −0.79 were observed between GY and DTH in South Asia during 2009–2014. Each year, we identified early-maturing germplasm with higher grain yield than the local checks. A positive trend was observed while estimating the breeding progress across five years for high-yielding early-maturing heat tolerant wheat compared to the local checks in South Asia. The results suggests the potential of the high-yielding early-maturing wheat lines developed at CIMMYT in improving wheat production and maintaining genetic gains in South Asia.
    No preview · Article · Apr 2016 · Field Crops Research
  • No preview · Conference Paper · Mar 2016
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    [Show abstract] [Hide abstract] ABSTRACT: In wheat, breeding for high yield and resistance to diseases has always been a priority although quality components are no less important. With a view to assess the existing variability in spring wheat genotypes, 3322 advance breeding lines comprising nine nurseries (29th, 30th, 31st, 32nd SAWSN, 44th, 45th 46th, C47th IBWSN and EHTN) obtained from CIMMYT, Mexico under BMZ funded project were evaluated during 2012-13 winter season at the ICAR-Indian Institute of Wheat and Barley Research, Karnal. The data on quality and nutritional traits viz., protein content (dry basis), sedimentation value, grain hardness index (GHI), iron and zinc content were recorded as per standard protocols. The variability, correlation and quantile distribution for each of the quality traits was analysed following SAS programme. The maximum coefficient of variation was observed for grain hardness index (19.73%), followed by zinc content (15.02%), sedimentation value (12.66%), iron content (10.39%) and protein content (8.42%). The protein content was positively associated with iron content (0.327**), zinc content (0.295**), sedimentation value (0.102**), while negative association (-0.063**) was observed with grain hardness index. Iron and zinc content were observed to be significantly associated with each other. The 75% quantile for protein content was 15.2% indicating 25% of genotypes had high protein content (>15%). For sedimentation value, 90% quantile was 50ml and 31ml at 1% quantile. 25% genotypes were found to be having >74 GHI, while 5% genotypes had below 35 GHI. 5% genotypes (95% quantile) had iron content more than 49.5 ppm. In case of zinc content, only1% genotypes were identified as superior (>40ppm). The large number of genotypes screened exhibited sufficient variability for various nutritional and processing quality traits in spring wheat. Promising advance lines identified for one or more of the quality traits are being further evaluated and utilized in the breeding programme.
    Full-text · Conference Paper · Sep 2015
  • No preview · Article · Sep 2015 · Indian Journal of Genetics and Plant Breeding
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    Full-text · Conference Paper · Mar 2015
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    G.S. Jasudasu · R. Chand · A.K. Singh · V.K. Mishra · A.K. Joshi
    [Show abstract] [Hide abstract] ABSTRACT: An experiment was conducted to determine the efficiency of two spores counting methods from wheat seeds. Seeds 40 genotypes collected from the Wheat Association mapping population from the Varanasi for the recovery of Bipolaris sorokiniana spores. The correlation(r) between these two methods was (0.8). Results indicated that Nematode Plate count Method (NPM) was superior to the Washing Test method (WT). The mean recovery of spore in the nematode count plate was significantly higher than the washing test method. In Nematode Plate Method, the spore count distributed with a mean of 126.47/50 seed while in the Washing Test, the spore count mean was 64.15. Recovery of different of black and mixed population was recorded from the seed. White population could not be detected from samples. In the present study, validation and utility of two SSR markers associated with spot blotch resistance in wheat (Triticum aestivum L.) was undertaken. Two primers were used for assessment of genetic variability among 40 wheat genotypes. The phenotypic data in the form of spore load of individual genotypes was compared with the genotypic data. The selected SSR primers showed a high level of polymorphism. Xgwml48 produced 170 bp band in resistant cultivar, while Xgwm111 amplified 150 bp band in resistant cultivar. SSR marker Xgwml48 linked with QTL, QSb.bhu-2B and Xgwm111 is linked with QSb.bhu-7D.
    Full-text · Article · Jan 2015
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    [Show abstract] [Hide abstract] ABSTRACT: 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 2.0–2.5% 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.
    Full-text · Article · Nov 2014 · Field Crops Research
  • [Show abstract] [Hide abstract] ABSTRACT: In order to accelerate genetic gains of wheat yield potential given the lack of substantive information on its genetic basis, physiological approaches can be applied in hybridization strategies to achieve cumulative gene action through combining complementary physiological traits. Lines of the 1st and 2nd WYCYT included selected progeny (NEW lines) generated by crossing material with superior expression of photosynthetic capacity (source) to lines showing favorable expression of spike fertility traits (sink), and selected for yield potential at MEXPLAT; an environment where yields of up to 10 t/ha are achieved. Results of multi-location yield trials in Mexico and internationally -at a total of 25 sites- provide a first proof of concept that yield potential can be increased through strategic physiological crossing.. The results were especially promising in terms of increased biomass and radiation use efficiency. Averaging over international trials, yield and biomass of the best NEW lines were expressed at 8% and almost 20% over local checks, respectively in the 2013 spring wheat cycle.
    No preview · Conference Paper · Mar 2014
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    Full-text · Dataset · Jan 2014
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    R. Prasad · L.C. Prasad · R. Chand · A.K. Joshi
    [Show abstract] [Hide abstract] ABSTRACT: A set of 1662 barley accessions from India, ICARDA and CIMMYT were evaluated over three cropping seasons for reaction to spot blotch (causative agent Cochliobolus sativus) infection, along with the four phenotypic traits waxiness, anthocyanin pigmentation, plant height and leaf angle. Only 5% of the entries showed any substantial resistance, while 31% were moderately resistant, 40% moderately susceptible and 24% fully susceptible. The range in mean area under disease progress curve (AUDPC) percent days and days to maturity of the best-performing 25 entries was 250-463 and 88-111, respectively, and most out-performed the best check entry. Four crosses were made between one of the resistant entries (EMBSN-27-4-1, BCU 570, BCU 455 and HMBSN-47-1) and one of the susceptible ones (RD 2503, RD 2624, RD 2614 and CIHO 3510). The F3 and F4 generations were used to test for genetic linkage between spot blotch reaction and the four phenotypic traits. Both waxiness and narrow leaf angle were positively associated with resistance, but neither plant height nor anthocyanin pigmentation was.
    Full-text · Article · Dec 2013 · Field Crops Research
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    [Show abstract] [Hide abstract] ABSTRACT: 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.
    Full-text · Article · Sep 2013 · Field Crops Research
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    [Show abstract] [Hide abstract] ABSTRACT: Six varieties viz., Chirya-1, Chirya-3, Chirya-7, Yangmai-6, Ning-8201 and Ning-8319 known for their resistance to spot blotch were crossed with the most susceptible parent i.e., Sonalika for studying inheritance pattern and establishing allelic relationship among different resistance sources. Disease severity of F ’s were intermediate to slightly tilted towards resistant 1 parents and thus indicated either no dominance or partial dominance. Progeny rows of these crosses were evaluated in the F 3 and F generations. Disease severity for each progeny rows was measured at three different growth stages viz., late anthesis 4 (69), late milk (77) and early dough (83) stages. Based on disease severity, the F , F and F progenies were grouped into three 3 4 5 classes: homozygous dominant, segregating and homozygous susceptible. Based on this ratio, number of effective genes was estimated following ÷2 analysis and quantitative approaches. Chirya-1, Chirya-3, Chirya-7, Yangmai-6 and Ning-8201 showed involvement of two genes in resistance while, Ning-8319 showed the presence of three resistance genes to spot blotch. Resistant × resistant crosses were made to establish the allelic relationship of resistance genes. The F progeny of all the 3 crosses did not show susceptible plants. This proved that at least one gene was common among parents for resistance. However, the appearance of transgressive segregants was an indication of the non-allelic relationship. The present study also indicated the possibility of achieving enhanced resistance through gene pyramiding.
    Full-text · Article · Jul 2013
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    R Prasad · LC Prasad · R Chand · AK Joshi
    [Show abstract] [Hide abstract] ABSTRACT: Spot blotch is one of the very destructive disease of barley and it is very complicated to know the degree of resistance of the parents because of variable nature of the pathogen and expression of resistance genes of the parents. It is therefore, to know the allelic relationship for resistance total eight resistance barley genotypes namely DWR 39, K 729, BCU 455, ISBCB-03-153, BCU 73, NDB 1180, HUB 20 and DWR 46 were used and crossed in half diallelic fashion and generated 28 cross combitions. F1's were selfed to get F2 and F2 advanced to get F3 follwed by single seed method including all the the crosses. Data of each generation along with parents were recorded. In the F3 generations of 28 crosses 10 crosses showed a narrow range of disease severity and lacked suceptible plants completely. This indicated substantial evedence that these parents carried similar resistance genes conferring resistance and in seven crosses the range od disease deverity/AUDPC was wider but it was lesser than the remaining eleven crosses whic suggesting at leat one gene common in parents of those crosses while remaining crosses showed wide range and indicates absence of common genes for resistance and appearance of transgressive segregants were an indication of non allelic relationship.
    Full-text · Conference Paper · Jan 2013
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    [Show abstract] [Hide abstract] ABSTRACT: Leaf rust caused by Puccinia triticina, is a globally important fungal disease of wheat (Triticum aestivum L. em. Thell), resulting in significant yield losses, sometimes up to 40% worldwide. In this study we investigated slow rusting resistance at pathological and molecular level. Fifteen (15) wheat genotypes which also included multiple crosses with the aim to characterize pyramid resistance genes, including slow rusting genes like Lr46 and Lr50 were evaluated for disease severity percent, latent period and incubation period under field conditions. Detached leaf assay was also performed with three virulent pathotypes viz., 21R55 (104-2), 121R63-1 (77-5) and 29R45 (12-5), under controlled laboratory conditions. Genotypes, KIRITATAI//HUW234+LR34/PRINIA, WAXWING*2/TUKURU, WBLLI*2/KIRITATI, KAMBI*2/-BRAMBLING and KAMBI*2/KIRITATI were very close to near immunity and showed comparatively higher level of resistance against all the three pathotypes. Disease severity in resistant genotypes was traced type 5 to 6% in both years, while it was 60 to 80% in the case of susceptible genotypes, that is, 'Agra Local' (S1). Similar pattern was observed for AUDPC, that is, <250.0 in the resistant genotypes, while it was beyond 1000.0 in 'Agra Local'. The shorter mean latent (7.67) and incubation period (6.0) was observed in susceptible genotypes, that is, 'Agra Local' to all the resistant genotypes, that is, LP (10 to 12) and IP (9 to 10); while testing against all the three different pathotypes. Linked microsatellite markers were used to confirm the presence of different rust resistance genes required to achieve near immunity. Out of 10 primers, nine produced gene specific bands with all genotypes except the control, that is, Agra Local. Genotypes which showed slow rusting, had longer latent period and incubation period as well as reduced percent disease severity and confirmed the presence of four to five resistance genes including slow rusting genes, that is, Lr46 and Lr50. This indicates that these genotypes have potential durable resistance and can be used as parental lines in the development of more durable rust resistance.
    Full-text · Article · Nov 2012 · AFRICAN JOURNAL OF BIOTECHNOLOGY
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    [Show abstract] [Hide abstract] ABSTRACT: Aim Zinc (Zn) fertilization is an effective agronomic tool for Zn biofortification of wheat for overcoming human Zn deficiency. But it still needs to be evaluated across locations with different management practices and wheat cultivars, since grain Zn concentrations may be significantly affected by locations, cultivars and management. Materials Field experiments were conducted over 3 years with the following four Zn treatments: nil Zn, soil Zn application, foliar Zn application and soil + foliar Zn application to explore the impact of Zn fertilization in Zn biofortification of wheat. The experiments were conducted at a total of 23 experimental site-years in China, India, Kazakhstan, Mexico, Pakistan, Turkey and Zambia. Results The results showed that foliar Zn application alone or in combination with soil application, significantly increased grain Zn concentrations from 27 mg kg−1 at nil Zn to 48 and 49 mg kg−1 across all of 23 site-years, resulting in increases in grain Zn by 84 % and 90 %, respectively. Overall, soil Zn deficiency was not a growth limiting factor on the experimental sites. A significant grain yield increase in response to soil Zn fertilization was found only in Pakistan. When all locations and cropping years are combined, soil Zn fertilization resulted in about 5 % increase in grain yield. Foliar Zn application did not cause any adverse effect on grain yield, even slightly improved the yield. Across the 23 site-years, soil Zn application had a small effect on Zn concentration of leaves collected before foliar Zn application, and increased grain Zn concentration only by 12 %. The correlation between grain yield and the effectiveness of foliar Zn application on grain Zn was condition dependent, and was positive and significant at certain conditions. Conclusion Foliar Zn application resulted in successful biofortification of wheat grain with Zn without causing yield loss. This effect of Zn fertilization occurred irrespective of the soil and environmental conditions, management practices applied and cultivars used in 23 site-years. Foliar Zn fertilizer approach can be locally adopted for increasing dietary Zn intake and fighting human Zn deficiency in rural areas.
    Full-text · Article · Oct 2012 · Plant and Soil
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    [Show abstract] [Hide abstract] ABSTRACT: 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.
    Full-text · Article · Oct 2012 · Field Crops Research
  • B.M. Bashyal · Ramesh Chand · L.C. Prasad · A.K. Joshi
    [Show abstract] [Hide abstract] ABSTRACT: Fourteen barley genotypes were tested in field condition for their reaction to helminthosporol toxin of Bipolaris sorokiniana of barley at third node detectable, beginning of flowering and medium milk stage. Appearance of necrotic symptom was highly influenced by growth stage of genotypes. Symptom appeared early in medium milk stage (GS 75) and it took maximum time at third node detectable stage (GS 33). RD2503 has taken three days and BCU3839 has taken 14.8 days for the necrotic symptom at growth stage 75. Further percentage of infiltered area also increased at growth stage 75 compared to other stages. Growth stage 75 identified as most appropriate growth stage for the screening of barley genotypes to helminthosporol.
    No preview · Article · Aug 2012 · Indian Journal of Agricultural Sciences
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    [Show abstract] [Hide abstract] ABSTRACT: Two hundred twenty five isolates of B. sorokiniana of barley were studied for their morpho-pathological characterization and were grouped in to four categories (1) dull white to slight black, gel type cottony growth (DW), (2) white fluffy growth (WE), (3) suppressed white growth (SW) and (4) black fluffy growth (BF).The frequency of BE isolate was highest (39.6 %) whereas SW isolates displayed lowest frequency (7.1 %). The group IV (BE) isolate was most aggressive. Sixty four purified isolates, sixteen from each of the four groups, were taken for RAPD analysis. Twenty RAPD primers were tested to detect the variability among these four identified groups. A total of 204 bands were amplified with 100% polymorphism using 20 primers. Dendrogram based on molecular polymorphism displayed considerable diversity within and between groups of 64 isolates which displayed four morpho-pathological groups into seven clusters. Specific DNA bands were identified for the selected isolates. The distinct markers may potentially be employed as genetic fingerprints for specific strain identification and classification in future.
    Full-text · Article · Feb 2012 · Indian Journal of Genetics and Plant Breeding
  • B. M. BashyaL · Ramesh Chand · L. C. Prasad · A. K. Joshi
    [Show abstract] [Hide abstract] ABSTRACT: Eighty barley genotypes were evaluated for partial resistance components of spot blotch disease of barley caused by Bipolaris sorokiniana under field conditions. Barley genotypes were inoculated with 29 B isolate of Bipolaris sorokiniana and the Area Under Disease Progress Curve (AUDPC), size of lesion, number of lesions leaf-1 and number of spores lesion-1 were recorded for penultimate leaves. A wide range of variation was observed for the components of partial resistance in barley genotypes. AUDPC and size of lesion identified as first principal components for the resistance. Further cluster analysis clustered genotypes into 10 groups and barley genotypes BCU5592, BCU5613, BCU1452, BCU138 and BCU133 exhibited low AUDPC, smaller lesion size, less number of lesions leaf-1 and less number of spores lesion-1. Selecting these genotypes exhibiting resistant components could be helpful in reducing losses caused by disease and thus contribute to increased yield.
    No preview · Article · Jun 2011 · Acta Phytopathologica et Entomologica Hungarica
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    [Show abstract] [Hide abstract] ABSTRACT: An important step towards reducing the vulnerability of wheat in Africa and Asia to the Ug99 race of the stem rust pathogen is the substitution of current susceptible varieties with superior resistant varieties. In the 2008–2009 cropping season both seed multiplication and dissemination of Ug99 resistant varieties were initiated in Afghanistan, Bangladesh, Egypt, Ethiopia, Iran, India, Nepal and Pakistan. Ug99 resistant varieties must occupy about 5% of the area sown to wheat in each country to ensure sufficient seed to displace current popular varieties. Because of the underdeveloped seed industry and small farm sizes in most of these countries, various strategies are being applied for rapid multiplication and dissemination of resistant varieties. Approaches being used include pre-release seed multiplication while candidate resistant lines are being tested in national evaluation trials and farmer participatory selection. Resistant varieties are already released in Afghanistan, Bangladesh, Egypt and Pakistan and more varieties are expected to be released in 2010 in these and other countries. Our results show that some new Ug99 resistant lines have yield superiority over dominant local varieties. Activities and progress in seed multiplication using existing and new Ug99 resistant varieties are discussed. Keywords Puccinia graminis f. sp. tritici –Farmer participation–Seed distribution systems–Stem rust– Triticum aestivum –Participatory varietal selection–Ug99
    Full-text · Article · May 2011 · Euphytica