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Search Results: 1 - 10 of 325654 matches for " S. Farooq "
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Rapid Clonal Propagation of Tamarindus indica (L) Using Explants from Adult Trees
S.A. Farooq,Talat T. Farooq
Pakistan Journal of Biological Sciences , 2003,
Abstract: Tamarindus indica (Tamarind) is a wild tropical tree species, over exploited commercially in third world countries but remains unimproved and neglected. Tissue culture has the potential to propagate elite genotypes of trees. Micropropagation of Tamarindus indica was achieved through adventitious shoots or axillary bud proliferation from nodes of adult trees (10-15 years old) on MS medium with BA, Kin. Proliferation of shoots continued on the medium with reduced levels of growth regulators and vitamins. Rooting was obtained with IBA. Nodal explants from young shoots responded better in comparison with the explants from mature shoots in the early stages of establishment of cultures and rooting of shoots.
Inter- and Intraspecific Variations in Wild Rice Species Detected Through Isozyme Markers
N. Iqbal,S. Farooq
Pakistan Journal of Biological Sciences , 2001,
Abstract: Isozyme analyses were used to detect inter- and intraspecific variation in different accessions of wild rice species, 0. officinallis and 0. punctata. Some F1 hybrids between cultivated and wild rice species were also utilized. Fresh leaf extracts were electrophoresed on polyacrylamide gels. Different isozymes viz., Esterases, Glutamate oxaloacetate transaminases and peroxidases were used as biochemical markers. On the basis of isozyme banding profiles, distinct variations were observed between and within the two wild rice species and their different accessions. Based on polymorphic isozyme profiles, hybrids of rice cultivars, Basmati 198 x 0. officinalis, Nonabokra x 0. malampuzhaensis ace: 100957 and EF-6 x 0. malampuzhaensis ace: 100957 were also identified. Our study demonstrated that isozyme markers can successfully be used for detection of genetic diversity as well as for the identification of hybrids.
Food Security in the New Millennium-I: The Role of Agricultural Biodiversity
S. Farooq,F. Azam
Pakistan Journal of Biological Sciences , 2002,
Abstract: This paper describes the concept of agricultural biodiversity and its importance in present and future food security. Some facts and figures are being presented in order to apprise the reader about the state of agricultural biodiversity in this country and elsewhere. The term agricultural biodiversity has been elaborated at length with special reference to the type of biodiversity available in Pakistan. The importance of biodiversity has been discussed in relation to its role in value addition to commercial crops in the form of resistance against pests and diseases. Its contribution, to human foodstuff, removal of genetic vulnerability and food security has also been discussed in detail. How agro-biodiversity has been utilized in crop production programmes and how rapidly it is being eroded, has also been described. Emphasis has been made on the conservation (both in situ and ex situ) of sites rich in agro-biodiversity along with its characterization and utilization in order to enhance its present status and to create new biodiversity to meet the future demand of crop improvement especially for tolerance to abiotic stresses.
Molecular Markers in Plant Breeding-lll: Practical Applications and Difficulties Encountered
S. Farooq,F. Azam
Pakistan Journal of Biological Sciences , 2002,
Abstract: Some of the empirical results obtained through the use of RFLP, AFLP, SSR and RAPD markers in the areas of DNA fingerprinting, measurement of genetic distance and heterosis, marker-assisted selections and abiotic stress tolerance are being described. Various difficulties that a user can encounter during the ontogeny of marker`s application have also been discussed. Marker mediated varietal fingerprinting and germplasm characterization appeared most common and most pervasive application with AFLP and SSR markers. Being cost effective, easy to handle and devoid of any radioisotope requirement, SSR markers are considered as the most suitable and reliable system for DNA fingerprinting. Capturing heterosis appeared most difficult with very little success due to lack of a facile marker system that could unconditionally identify the heterotic groups, population and progenies. Marker-assisted selections for qualitative traits appeared most successful after DNA fingerprinting while for quantitative characters, major disease resistance genes and genes controlling QTL for abiotic stress tolerance, the success is limited. It is anticipated that application of markers will remain restricted in these areas till the allele-specific markers are available and the cost of marker analysis is reduced significantly.
Molecular Markers in Plant Breeding-I: Concepts and Characterization
S. Farooq,F. Azam
Pakistan Journal of Biological Sciences , 2002,
Abstract: Plant breeding is a combination of principles and methods of changing the genetic constitution of a plant to make it more suitable for human needs. Conventional plant breeding has evolved with the passage of time from simple seed saving of the best harvest to the selection of seeds according to the laws of Mendel. With the advent of morphological and biochemical markers, the selection process has hastened and the scope of conventional plant breeding increased many folds during the recent years. However, the process that actually revolutionized the plant breeding in the 20th century was the realization that there exist a widespread polymorphism in natural populations, the degree of which can be assessed by sequencing or making restriction maps: an application of new tools of molecular biology. The first and the foremost molecular markers system i.e., restriction fragment length polymorphism (RFLP) was developed in early 1980. These are co-dominant markers and are available in unlimited number. Another breakthrough was the emergence of polymerase chain reaction (PCR) in 1990. With this technology, a new generation of DNA markers such as randomly amplified polymorphic DNA (RAPDs), sequence characterized amplified regions (SCARs), sequence tagged sites (STS), single polymorphic amplification test (SPLAT), variable number of tendom repeats (VNTRs), amplified fragment length polymorphism (AFLP), DNA amplification fingerprinting (DFA), single strand conformational polymorphism (SSCP), single nucleotide polymorphism (SNPs), micro-satellites or short tandem repeats (STRs), cDNA, DNA micro arrays and rDNA-ITS were introduced into the modern plant breeding systems. The concept of DNA based markers has increased our ability many folds, to follow minute regions of chromosome through opportunities such as map based cloning and Marker-assisted Plant (MAP) Breeding. In MAP breeding, the new ideas and concepts have been introduced which need to be understood thoroughly, before applying these ideas in practical breeding programmes particular in country like Pakistan where application of molecular biological approaches are still in its infancy. In order to achieve this objective, efforts were made to write a series of review articles in which concept of MAP breeding is being described thoroughly yet in a simple way so that student and researchers can build their understanding of plant molecular breeding and application of DNA based markers for the genetic dissection of qualitative and quantitative traits. In the present paper, concepts of MAP breeding and the type and cha
Nitrification Inhibition in Soil and Ecosystem Functioning An Overview
F. Azam,S. Farooq
Pakistan Journal of Biological Sciences , 2003,
Abstract: Form (NH4 or NO3) and availability of N has significant implications to the functioning and sustainability of agroecosystems. Most of the fertilizer nitrogen (N) applied to agricultural soils is in the form of NH4 or NH4-forming fertilizers. This form of N is rapidly oxidized to NO3 by nitrifying microorganisms leading to significant losses of N through NO3-leaching and denitrification. Both denitrification and NO3-leaching have environmental implications and economic concerns. Strategies have therefore been sought to regulate the process of nitrification leading to its complete or partial inhibition. Indeed, climax ecosystems are developed in such a way that the process of nitrification is already fairly inhibited. This paper presents an overview on: I) the process of nitrification, ii) microorganisms involved, iii) the implications of nitrification and nitrification inhibition to ecosystem functioning and finally iv) the methods to inhibit nitrification.
Food Security in the New Millennium-II. The Role of Agriculture Biotechnology
S. Farooq,F. Azam
Pakistan Journal of Biological Sciences , 2002,
Abstract: Plant breeding in its primitive form is being practiced since the transition of human being from hunter/gatherers to settled agriculturist, approximately 10,000 thousand years ago. Without knowing genetics and its principal, it was used genetics to modify crops and their products. The selection of plants with best characteristics as source of next year seeds quickly resulted into domestication of crops that were distinct from their wild relative. Genetic modification (GM) has emerged against this historic background of breeding and selection and is thus, the extension of existing techniques and not something, which is unprecedented. In present paper, efforts have been made to review situation (s) that are responsible for the origin of genetically modified (transgenic) approaches to be used for crop improvement. The outcome of these approaches and the credibility of the resultant products along with their impact and significance on crop productivity in particular have also been reviewed. Impact of GM technology on the poor farmers in the developing countries with special reference to their needs and resources has been discussed in detail. The current status of genetically modified crops in the developed countries and also in the developing countries willing to adopt this technology albeit slowly has also been described along with their fears and concerns in order to provide the readers the choice to select this technology or otherwise according to their own needs and resources. The paper also provides information on the genetically modified products that can have significant impact in improving nutritional status of food generally consumed by millions of people living in the hart land of poverty that is South Asia and Sub-Saharan Africa.
An Appraisal of Methods for Measuring Symbiotic Nitrogen Fixation in Legumes
F. Azam,S. Farooq
Pakistan Journal of Biological Sciences , 2003,
Abstract: Symbiotic nitrogen fixation by legumes is the major natural process of adding nitrogen into the biosphere amounting to about 35 million tons annually. The process of nitrogen addition to the ecosystems and its further fate is such as to pose minimum threat to environmental cleanliness relative to N used as chemical fertilizers. Therefore, it has been of great interest not only to understand the basics of nitrogen fixation process but also to quantify the amount of N added to a system under different conditions. This is important in order to quickly screen the available germplasm for its potential of biological N2 fixation and to devise strategies for further improving the process under different ecological conditions. A critical evaluation of some common methods of studying N2 fixation in legumes is presented.
Elevated CO2–Does it Really Matter for Plants That Are Already Experiencing Higher than Ambient Levels?
F. Azam,S. Farooq
Pakistan Journal of Biological Sciences , 2005,
Abstract: Atmospheric concentration of CO2 has increased significantly over the past few decades and so have the concerns about the greenhouse effect and global warming. One of the extensively explored aspects is the response of ecosystem components in terms of performance and productivity. A host of information thus generated suggests a positive effect of elevated CO2 on functioning of plants from seed germination through maturation vis-a-vis rhizospheric microbial functions. Amazingly, most (if not all) of the researches deal with plant responses to CO2 at levels twice that of ambient with a view that fossil fuel burning and increased agricultural activity are adding substantially to the atmospheric CO2 . As such, hardly any attention has been paid to the contribution of soil respiration (includes that of microbes and plant roots) to CO2 concentration within the soil matrix as well as above the soil surface. This study presents an analysis of the available literature to demonstrate that by default the plant communities are already functioning at elevated levels of CO2 . Any further increase due to human intervention (especially fossil fuel burning) may not have a significant effect on plant functions and productivity. Hence the potential dangers of elevated CO2 resulting from fossil fuel burning should not be considered as alleviated through increased plant productivity.
Molecular Markers in Plant Breeding-II. Some Pre-requisites for Use
S. Farooq,F. Azam
Pakistan Journal of Biological Sciences , 2002,
Abstract: This paper describes some of the pre-requisites for applying molecular markers in plant breeding or crop improvement programmes. This includes, possible answers to some of the very pertinent questions regarding marker-assisted plant breeding. For example, I) how an effective marker system is to be selected, ii) how, when and where these expensive technologies can be used efficiently and iii) what particular problem would be solved just by using a particular marker system. The most commonly used marker systems including restriction fragment length polymorphism (RFLP), amplified fragment length polymorphism (AFLP), micro-satellite or simple sequence repeat (SSR) and random amplified polymorphic DNAs (RAPDs) have been described in detail. The advantages and disadvantages (if any) of these marker systems and their practical utilization in different areas of crop improvement programmes have been discussed. Different methods of integrating molecular markers in conventional plant breeding programmes have also been described in greater detail with special reference to varietal identification and germplasm characterization, marker-assisted selection for qualitative and quantitative traits and abiotic stress tolerance. It is suggested that in all these cases, cost-effective application of markers can best be achieved through collaboration with those who excel in this technology. This collaboration is also necessary in order to integrate the systems and technologies to deliver the product in minimum possible time and with minimum extra input/investment in terms of operational expenses.
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