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Jat R.A.,Indian International Crops Research Institute for the Semi Arid Tropics | Jat R.A.,Directorate of Groundnut Research | Wani S.P.,Indian International Crops Research Institute for the Semi Arid Tropics | Sahrawat K.L.,Indian International Crops Research Institute for the Semi Arid Tropics
Advances in Agronomy | Year: 2012

Relatively less attention has been paid on the use of conservation agriculture (CA) in the arid and semi-arid tropics (SAT), although a lot of information is available from humid and sub-humid regions globally. The objective of this review is to focus on the use of CA - its status, problems and prospects in the semi-arid tropical regions with emphasis on Asia and Africa. The information on the use of CA in SAT regions is summarized and put in context with the information available and lessons learnt on the use of CA in relatively vast tracts of land, especially in Brazil, North America, and Australia. Clearly, there are several bottlenecks in the use of CA in the SAT regions of Asia and Africa especially under rainfed agriculture. Among the major constraints to the use of CA in these regions include insufficient amounts of residues due to water shortage and degraded nature of soil resource, competing uses of crop residues, resource poor smallholder farmers, and lack of in-depth research in the SAT regions of Africa and to a lesser extent in Asia. The exception in the implementation of CA is of course the wheat-rice system in south Asia under irrigated conditions. The use of CA in the wheat-rice system of the Indo-Gangetic Plains (IGP) of south Asia has been relatively well researched during the last decade or so. However, in rainfed systems of the drier regions, relatively less attention has been given to develop research strategy to overcome the constraints to the adoption of CA. Examples are given from Brazil, Australia and North America as to how CA has been widely adopted in those regions as well as from Africa where CA is being promoted through active support of donor agencies. Obviously, there is need for strategic long-term research in the SAT regions for exploring the prospects in the face of major constraints faced to the adoption of CA, before CA could be taken to the farmers' door steps. © 2012 Elsevier Inc. Source

Photorespiration is generally considered to be an essentially dissipative process, although it performs some protective and essential functions. A theoretical appraisal indicates that the loss of freshly assimilated CO2 due to photorespiration in well-watered plants may not be as high as generally believed. Even under moderately adverse conditions, these losses may not exceed 10%. The photorespiratory metabolism of the source leaves of well-watered and well-nourished crop plants ought to be different from that of other leaves because the fluxes of the export of both carbohydrates and organic N-transport compounds in source leaves is quite high. With a heuristic approach that involved the dovetailing of certain metabolic steps with the photorespiratory cycle (PR-cycle), a novel network is proposed to operate in the source-leaves of well-watered and well-nourished plants. This network allows for the diversion of metabolites from their cyclic-routes in sizeable quantities. With the removal of considerable quantities of glycine and serine from the cyclic route, the number of RuBP oxygenation events would be several times those of the formation of hydroxypyruvate. Thus, to an extreme extent, photorespiratory metabolism would become open-ended and involve much less futile recycling of glycine and serine. Conversion of glyoxylate to glycine has been proposed to be a crucial step in the determination of the relative rates of the futile (cyclic) and anabolic (open-ended) routes. Thus, in the source leaves of well-watered and well-nourished plants, the importance of the cyclic route is limited to the salvaging of photorespiratory intermediates for the regeneration of RuBP. The proposed network is resilient enough to coordinate the rates of the assimilation of carbon and nitrogen in accordance with the moisture and N-fertility statuses of the soil. © 2013 Elsevier GmbH. Source

Nautiyal P.C.,Directorate of Groundnut Research | Shono M.,Okinawa Sub tropical Research Station
Biologia Plantarum | Year: 2010

This communication examines the role of small heat shock proteins (sHsps) targeted to mitochondria (Mt) and endoplasmic reticulum (ER) in tomato plants (Lycopersicon esculentum Mill.) under heat stress. Genetic response of transgenic and wild type plants varied under optimum, moderately elevated and elevated temperature. In optimum temperature higher biomass was recorded in wild type than the transgenic lines, whereas in moderately elevated temperature biomass increased in Mt-sHsp line. Also, net photosynthetic rate (PN) increased in Mt-sHsp line in both the elevated temperatures, though higher in moderately elevated. Cell membrane stability (CMS) improved in all the lines after exposure to elevated temperatures, but always remained higher in transgenic lines. Transgenic lines expressed sHsps in different temperature regimes in both vegetative and reproductive parts, while wild type expressed such proteins only after 1 h of heat shock. © 2010 Springer Science+Business Media B.V. Source

Kumar G.D.S.,Directorate of Groundnut Research | Popat M.N.,Junagadh Agricultural University
Crop Protection | Year: 2010

Aflatoxins, produced by the fungi Aspergillus flavus Link ex Fries and Aspergillus parasiticus Speare, are the major toxins affecting the quality of groundnuts (Arachis hypogaea L.) meant for human consumption. Groundnuts can be infected with aflatoxin-producing fungi pre-harvest, at harvest and post-harvest. This survey was conducted in Gujarat province in India in order to assess farmers' and other stakeholders' (extension staff and traders) perceptions and knowledge of aflatoxin contamination of groundnuts and to evaluate the agronomic and market practices used to manage it. The survey investigated the effects of the socioeconomic background of the farmers. The results showed that the socioeconomic and psychological characteristics, viz. education, caste, farm size, social participation, extension participation, market orientation, economic motivation, innovativeness and perception had positive and significant associations with farmers' knowledge. The extension staff and traders had a good understanding of the problem and of the importance of managing aflatoxin contamination but farmers did not. Farmers' who practised effective crop husbandry in order to increase production were unwittingly managing aflatoxin contamination to some extent. Their marketing practises showed that the problem of aflatoxin contamination was neglected at both the production and marketing stages. We suggest that extension agencies need to train farmers in the use of biological control agents, post-harvest management and identification of aflatoxin contamination. Partnerships need to be forged between research institutions, the departments of agriculture of various states, marketing agencies, NGOs, farmers' groups, consumer groups, agrochemical manufacturers and other stakeholders in order to develop strategies for addressing the problem of aflatoxin contamination. © 2010 Elsevier Ltd. Source

Kumar G.D.S.,Directorate of Groundnut Research | Popat M.N.,Junagadh Agricultural University
International Journal of Pest Management | Year: 2010

Groundnut (Arachis hypogaea L.) is a major oilseed crop of India. Groundnut has great potential for diversification, from oil extraction to food uses, due to its high nutritive value. Aflatoxin contamination is the major impediment to such diversification. Aflatoxins, produced by the fungi Aspergillus flavus and A. parasiticus, are the major toxins affecting the quality of groundnut meant for human consumption. The adoption of 'Aflatoxin Management Practices of Groundnut' (AMPG) is very important for reducing aflatoxin contamination. This study was undertaken with the aims of determining the extent of adoption of AMPG by farmers, to assess the constraints upon adoption of AMPG and to understand the relationship between adoption of AMPG by farmers and socio-economic and psychological factors. The results indicated that the majority of the farmers were unaware of aflatoxin contamination and hence had not adopted sowing, post-sowing and post-harvest aflatoxin management practices. The farmers with large land holdings were high adopters of AMPG compared to farmers with small land holdings. Socio-economic and psychological characteristics such as innovativeness, perception of groundnut quality, extension participation, socioeconomic status, market orientation and farm size significantly influenced the adoption of AMPG. Mass awareness campaigns need to be organized to improve the stakeholders' perception of groundnut quality and the ill-effects of consuming aflatoxin-contaminated products. © 2010 Taylor & Francis. Source

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