Author: Ravi Singh

QTL mapping of grain Zn and Fe concentrations in two hexaploid wheat RIL populations with ample transgressive segregation

Ravi Singh (2017)

More than 50% of undernourished children live in Asia and more than 25% live in Africa. Coupled with an inadequate food supply, mineral deficiencies are widespread in these populations; particularly zinc (Zn) and iron (Fe) deficiencies that lead to retard

Article

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA Quantitative Trait Loci Wheats Zinc Iron Hexaploidy

Rust diseases of wheat: concepts and methods of disease management

Ravi Singh (1992)

The rust diseases of wheat are among the most studied of the plant diseases. Since Tozzetti and Fontana in 1767, there has been almost an endless list of scientific publications concerning the rust pathogens, the rust diseases, and rust resistance. This publication reviews some of the more recent scientific literature concerning the pathogens Puccinia recondita f.sp. tritici, P. graminis f.sp. tritici, and P. striiformis f.sp. tritici; the diseases leaf rust, stem rust, and stripe rust; and the resistance to the pathogens. The goal is to provide a single source of information for isolated scientists and new students. Abrief history and general description of the wheat rusts are followed by adetailed summary of each of the rust diseases, their epidemiology, their hosts (including resistance), and their pathogens (including virulences). Methods for disease control through resistance, chemicals, and cultural methods are discussed. Techniques are presented for inoculum production, collection, and storage; inoculation methods; disease scoring; testing for resistance; epidemiology, yield loss, and physiologic race studies; isolation of resistance genes; and utilization of resistance.

Book

Epidemiology Plant diseases Rusts Triticum aestivum CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Adoption, management, and impact of hybrid maize seed in India

Ravi Singh (1997)

This paper presents results of a 1995 survey of 864 maize-growing households in six states that account for more than 70% of India's maize area: Andhra Pradesh, Bihar, Karnataka, Madhya Pradesh, Rajasthan, and Uttar Pradesh. The current adoption of improved open-pollinated maize varieties (OPV) and hybrids is quantified, the relationship between adoption of improved germplasm and use of improved crop management practices is examinated, the economic impacts of adoption are estimated, farmers' seed procurement and management practices are described, and implications for maize research and development policy are discussed. On the whole, the survey results confirm that India's national maize seed industry is expanding rapidly. Since seed policy reforms were introduced in the late 1980s, the area planted to improved OPVs and hybrids has grown rapidly, and adoption of improved germplasm has fueled important changes in farmers' crop management practices. However, special policy measures may be needed to ensure that the benefits of improved germplasm are widely shared, such as the introduction of targeted input subsidies designed to reduce the cost of adopting improved seed and complementary inputs, government investment in irrigation infrastructure to reduce production risk in drought-prone environments, and market developmet initiatives to provide small-scale producers with access to stable and reliable outlets where they can sell surplus grain.

Book

Crop management Cropping patterns Economic analysis Maize Varieties CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Maize research, development, and seed production in India: contributions of the public and private sectors

Ravi Singh (1995)

This paper assesses the relative strengths and weaknesses of India's public and private maize seed industries and examines future options for maize seed industry policies. By 1992, nearly as many maize researchers worked for private seed companies as for public breeding programs - a significant departure from earlier years, when public organizations conducted virtually all maize research in India. Private companies have concentrated almost exclusively on developing hybrids, which perform best in the favorable environments where most commercial maize production takes place, whereas public breeding programs have produced a somewhat wider range of materials, including a number of open-pollinating varieties (OPVs) developed specifically for environments where maize production potential is low. Seed production in the public sector and especially in the private sector appears to be reasonably efficient, judging by the level of reported seed production costs. However, seed certification procedures are sometimes ineffective, and a significant proportion of the maize seed produced in India escapes rigorous quality controls. Growth in sales of proprietary hybrids produced by private companies has been much more rapid than growth in sales of public OPVs and hybrids, indicating that private companies deliver seed to farmers more effectively than public agencies. Government involvement in seed production and distribution seems destined to decrease, with responsibility for those functions gradually shifting to the private sector. Even so, private companies will require continuing support from the public sector. There will always be a need for the public sector to participate in the maize seed industry, particularly in supporting basic germplasm improvement research and research targeted at marginal production environments.

Working paper

Economic analysis Maize Research projects Seed production CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

The economic impact in developing countries of leaf rust resistance breeding in CIMMYT-related spring bread wheat

Ravi Singh (2004)

This study was undertaken to estimate the economic impact of efforts since 1973 by the International Maize and Wheat Improvement Center (CIMMYT) to develop spring bread wheat varieties resistant to leaf rust caused by Puccinia triticina. This wheat disease is of major historical and economic importance worldwide. The challenge in estimating the benefits lies in the pathogen’s ability to mutate to new races, which may infect previously resistant varieties. Thus, whereas productivity enhancement is often measured in terms of yield gains and increased supply, productivity maintenance is measured in terms of the yield losses avoided through resistance. An economic surplus approach adjusted for maintenance research and a capital investment analysis were applied to estimate the returns on CIMMYT’s investment. The results of the analysis suggest an internal rate of return of 41%. When discounted by 5%, the net present value was 5.36 billion 1990 US$, and the benefit-cost ratio 27:1. This implies that every 1990 US dollar invested in CIMMYT’s wheat genetic improvement over 40 years has generated at least 27 times its value in benefits from leaf rust resistance breeding in spring bread wheat alone. The findings of the study emphasize the importance of maintenance research in crop breeding programs.

Book

Bread Crop yield Disease resistance Economic analysis Genetic resistance Rusts Varieties CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Maize research, development, and seed production in India : contributions of the public and private sectors

Ravi Singh (1995)

This paper assesses the relative strengths and weaknesses of India's public and private

maize seed industries and examines future options for maize seed industry policies. By 1992, nearly

as many maize researchers worked for private seed companies as for public breeding programs - a

significant departure from earlier years, when public organizations conducted virtually all maize

research in India. Private companies have concentrated almost exclusively on developing hybrids,

which perform best in the favorable environments where most commercial maize production takes

place, whereas public breeding programs have produced a somewhat wider range of materials,

including a number of open-pollinating varieties (OPVs) developed specifically for environments

where maize production potential is low. Seed production in the public sector and especially in the

private sector appears to be reasonably efficient, judging by the level of reported seed production

costs. However, seed certification procedures are sometimes ineffective, and a significant proportion

of the maize seed produced in India escapes rigorous quality controls. Growth in sales of proprietary

hybrids produced by private companies has been much more rapid than growth in sales of public

OPVs and hybrids, indicating that private companies deliver seed to farmers more effectively than

public agencies. Government involvement in seed production and distribution seems destined to

decrease, with responsibility for those functions gradually shifting to the private sector. Even so,

private companies will require continuing support from the public sector. There will always be a

need for the public sector to participate in the maize seed industry, particularly in supporting basic

germplasm improvement research and research targeted at marginal production environments.

Working paper

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA Economic analysis Maize Research projects Seed production

38th Elite Selection Wheat Yield Trial

Ravi Singh (2019)

The Elite Selection Wheat Yield Trial (ESWYT) is a replicated yield trial that contains spring bread wheat (Triticum aestivum) germplasm adapted to Mega-environment 1 (ME1) which represents the optimally irrigated, low rainfall areas. Major stresses include leaf, stem and yellow rusts, Karnal bunt, and lodging. Representative areas include the Gangetic Valley (India), the Indus Valley (Pakistan), the Nile Valley (Egypt), irrigated river valleys in parts of China (e.g. Chengdu), and the Yaqui Valley (Mexico). This ME encompasses 36 million hectares spread primarily over Asia and Africa between 350S -350N latitudes. White (amber)-grained types are preferred by consumers of wheat in the vast majority of the areas. It is distributed to upto 200 locations and contains 50 entries.

Dataset

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA