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Singh, R.P.

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Singh
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Singh, R.P.

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  • Results of the Twenty-third International Spring Wheat Yield Nursery (ISWYN) 1986-87 = Resultados del 23 Ensayo Internacional de Rendimiento de Trigos Harineros de Primavera (ISWYN) 1986-87
    (CIMMYT, 1989) Rajaram, S.; Alcala de Stefano, M.; Pfeiffer, W.; Singh, R.P.; Cardenas, F.
    In the 1988 draft of CIMMYT's strategic plan CIMMYT in the Year 2000 and the document Report of the Third External Programme Review of the International Maize and Wheat Improvement Centre of the same year, wide adaptability (also termed "broad adaptation") to conditions over a range of broad agroecological zones known as "mega-environments" was recognized as one of the major thrusts for future wheat breeding efforts in an international context. The authors of the present article share the viewpoint that centers like CIMMYT should invest their resources in broad adaptability, leaving the task of breeding for specific adaptation to national agricultural research programs. CIMMYT's wheat breeding program dates back to 1944 as a bilateral venture between the Rockefeller Foundation and The Mexican Ministry of Agriculture. This program received an international mandate in the 1960's and continued evolving into the truly global operation it is today. Critics of CIMMYT's wheat breeding program have labeled the concept of wide adaptation as a banner for the propagation of a single, global variety. However, a careful examination of the facts will expose the flaws in such reasoning. Past products of breeding for wide adaptation at CIMMYT contributed to the Green Revolution, and our 45 years of existence on the global scene attests to the strong viability of wide adaptation as an alternative breeding methodology. On the other hand, while it is our strong belief that future work should exploit the strength of past plant breeding principles and methodologies, CIMMYT's wheat breeding program should also consider better alternatives if and when these become available. Indeed, over the last 45 years the concept itself of breeding for broad adaptation has greatly evolved, as new and distinct geographic areas came under the Wheat Program mandate. At present, the Program seeks to develop materials with general suitability for the five basic mega environments listed below (the year the Program began work specifically related to each mega-environment is given in parentheses): 1. Irrigated, optimum input ( 1944) 2. High rainfall (optimum for moisture but distinct from mega-environment I in the disease spectrum and the epidemiological vulnerability to various pathogens, including Septoria tritici 1972) 3. Semiarid and characterized by drought stress ( 1975) 4. Acid soil, especially aluminum toxicity (1975) 5. Wanner and characterized by heat stress (1981). The results of ISWYN since its inception have guided CIMMYT breeders in a dynamic program based on carefully conducted shuttle breeding. Over the years, these trials have revealed important genotype x environment interactions and allowed us to identify the five mega-environments proposed for spring wheats. So far, this information has proved relevant only for preliminary analyses done on ISWYN data; this may change, however, once the reliability of actual climatic data and genotype x environment interaction is recognized. Such a change would highlight the importance of the ISWYN. This report provides global, mega-environment, regional, and local summaries on data for the yield, agronomic traits, and disease response of 23rd ISWYN entries.
    Publication
  • Bugday hastalik ve zararlilari: tarlada tanima kilavuzu
    (CIMMYT, 1987) Prescott, J.M.; Burnett, P.A.; Saari, E.E.; Ransom, J.K.; Bowman, J.; De Milliano, W.A.J.; Singh, R.P.; Abeyo Bekele Geleta
    Publication
  • Results of the first International Scab Resistance Screening Nursery (SRSN) 1985-86
    (CIMMYT, 1986) Abeyo Bekele Geleta; Singh, R.P.; Alcala de Stefano, M.
    Fusarium head scab is a common wheat disease in many parts of the world where the crop is grown at low elevations under wam, humid conditions and lingering cloud cover. The disease is also economically important al high elevations where there is continuous daily rain and predominant doud cover during the wheat growing cycle, especially from flowering to physiological maturity. Scab is caused by various Fusarium species, including F. equiseti, F. culmorum, F. avenaceum, and F. nivale, but it is F. graminearum (perfect stage: Gibberella zeae) that generally causes the major scab epidemics and yield losses. The other species of Fusarium are of lesser importance, and occur only under conditions extremely favorable to their development. Evaluation for resistance to scah disease begant at CIMMYT during the early 1980s. Artificial inoculation methods were developed for the successful generation of artificial epidemics. Thousands of CIMMYT-drived wheats and introduced germplasm were evaluated for resistance under artificially-created epidemics at the Toluca research station of CIMMYT. Germplasm was also especially introduced from those areas where this disease occurs more severely, e.g., China and Brazil. The primary criterion for selecting gennplasm for the Scab Resistence Screening Nursery (SRSN) at this beginning phase was to identify lines with better resistance. This report is a summary of results obtained from the 1st SRSN with respect to various agronomic and disease resistru1ce chamcteristics. It is hoped that some of the material in this nursery will prove to be useful to our cooperators in Scab-endemic regions and the information contained herein will be of service to wheat breeders.
    Publication
  • Maladies et ravageurs du ble: guide d'identification au champ
    (CIMMYT, 1987) Prescott, J.M.; Abeyo Bekele Geleta; Bowman, J.; Burnett, P.A.; De Milliano, W.A.J.; Ransom, J.K.; Saari, E.E.; Singh, R.P.
    Depourvus de chlorophylle, ce en quoi ils different des autres plantes, les champignons n'ont done pas de capacite de photosyntese. Au lieu d'elaborer leur propre nourriture, ils absorbent des elements nutritifs qu'ils puisent dans les tissus marts ou vivants de l'hote. Ils se propagent de diverses manieres et peuvent etre transmis par la graine ou le sol, ou disperses par le vent, l'eau (de pluie ou d'arrosage), les insectes, les animaux et l'homme. L'infection par les champignons pathogenes est liee a divers facteurs: en general, leur reproduction requiert la presence d'eau a la surface de l'h6te et depend a la fois de la sensibilite de ce dernier, de la densite d'inoculum et de la temperature ambiante, et d'autres facteurs du milieu. Si certains champignons ne s'attaquent qu'a une ou a quelques especes hotes, d'autres par contre s'attaquent indistinctement a plusieurs d'entre elles. Les sympt6mes et l'evolution de la maladie dependent egalement de l'interaction entre le parasite et l'hote. Selan la nature des champignons qui sont a l'origine de la maladie, les symptomes peuvent etre semblables ou differents, ainsi leur identification categorique devra etre basee sur leur morphologie. Sauf indication contraire, les champignons dont ii sera traits ici sont ceux qui attaquent le ble tendre, le ble dur et le triticale.
    Publication
  • Wheat diseases and pests: a guide for field identification
    (CIMMYT, 1986) Prescott, J.M.; Burnett, P.A.; Saari, E.E.; Ransom, J.K.; Bowman, J.; De Milliano, W.A.J.; Singh, R.P.; Abeyo Bekele Geleta
    Publication
  • Enfermedades y plagas del trigo: una guia para su identificación en el campo
    (CIMMYT, 1986) Prescott, J.M.; Burnett, P.A.; Saari, E.E.; Ransom, J.K.; Bowman, J.; De Milliano, W.A.J.; Singh, R.P.; Abeyo Bekele Geleta
    This booklet is designed as a quick guide for identifying wheat and triticale diseases in the field. It is intended primarily for agricultural researchers, technicians, and farmers in developing nations, but will also be of value to others. The text comprises a brief description of the major wheat and triticale diseases, insect pests, nematodes, physiologic and genetic disorders, and mineral and environmental stresses. Complementing this text as an aid to identification are numerous color photographs, drawings, and a brief diagnostic key. Emphasis has been placed on economically significant diseases, but is not limited to them
    Publication