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Environmental stress can disrupt cellular structures and impair key physiological functions. Drought, salinity, and low temperature stress impose an osmotic stress that can lead to turgor loss. Membranes may become disorganized, proteins may undergo loss of activity or be denatured, and often excess levels of reactive oxygen species are produced leading to oxidative damage. As a consequence, inhibition of photosynthesis, metabolic dysfunction, and damage of cellular structures contribute to growth perturbances, reduced fertility, and premature senescence. Responses to environmental stresses occur at all levels of organization. Cellular responses to stress include adjustments of the membrane system, modifications of the cell wall architecture, and changes in cell cycle and cell division. In addition, plants alter metabolism in various ways, including production of compatible solutes that are able to stabilize proteins and cellular structures and/or to maintain cell turgor by osmotic adjustment, and redox metabolism to remove excess levels of ROS and re-establish the cellular redox balance. At the molecular level, gene expression is modified upon stress and epigenetic regulation plays an important role in the regulation of gene expression in response to environmental stress.

Set 1

1. Match the followings:

1. (a & i), (b & ii), (c & iii), (d & vi)
2. (a & ii), (b & i), (c & iv), (d & iii)
3. (a & iii), (b & i), (c & iv), (d & ii)
4. (a & iv), (b & ii), (c & i), (d & iii)

Introduction

Soil is the main source of nutrients for the plants. Soil also provides support for plant growth in various ways. Knowledge about soil health and its maintenance is critical to sustaining crop productivity. The health of soils can be assessed by the quality and stand of the crops grown on them. However, this is a general assessment made by the farmers. A scientific assessment is possible through detailed physical, chemical and biological analysis of the soils. Essential plant nutrients such as N, P, K, Ca, Mg and S are called macronutrients, while Fe, Zn, Cu, Mo, Mn, B and Cl are called micronutrients. It is necessary to assess the capacity of a soil to supply nutrients in order to supply the remaining amounts of needed plant nutrients (total crop requirement - soil supply). Thus, soil testing laboratories are considered nerve centres for nutrient management in crop production systems and plantation forestry.

Soils may have large amounts of nutrient reserves in them. All or a part of these reserves may not be of any use to crops because they may not be in plant-available form. For the purpose of estimation or analysis of plant-available soil nutrients, such methods are to be used that have been tested/verified for the correlation of nutrients extracted and their plant availability. This book describes internationally accepted and widely used methods. Apart from nutrients, soil pH estimation is also critical in the assessment of soil health. Generally, plants prefer soils that are close to either side of neutrality. However, there are acid- loving plants and also plants that can withstand high soil alkalinity. Hence, good yields and economic returns from farming are possible in acid and alkali soils. With proper amendments, still higher yields can be obtained in acid and alkali soils. Soil pH also has a considerable influence on the activity of soil micro-flora and on the availability of soil nutrients to crops. It is also important to estimate physical properties such as soil texture, structure, bulk density, soil colour, water content and soil temperature.

Identification of DNA as the Genetic Material

Experiments with pneumococcus suggested that DNA is the genetic material

Hershey and Chase provided evidence that the genetic material injected into the bacterial cytoplasm is T2 phage DNA

RNA functions as the genetic material in some viruses Work Before Watson and Crick

Nucleotides are the building blocks of nucleic acids

Nucleotides are linked together to form a strand

In 1869, Miescher first isolated DNA and named it “nuclein.”

In 1902, Archibald Garrod linked heredity to enzyme (protein) defects. In 1909 he published a book entitled “Inborn Errors of Metabolism.”

In 1928, Griffith identified a “transforming factor” that transmitted infectiousness in bacteria.

In 1944, Avery, MacLeod and McCarty showed that the transforming factor was DNA)

In 1950, Hershey and Chase, using their famous “blender” experiment, confirmed that DNA, not protein, is the genetic material.

The work of chemist Phoebus Levene showed that DNA includes deoxyribose, nitrogenous bases, and phosphates, in equal proportions.

Chargaff s data showed that the number of purines equals the number of pyrimidines.

Using Rosalind Franklin’s X-ray diffraction patterns, Watson and Crick deduced that DNA is a double helix

Black pepper, christened as “King of spices” and “Black gold” is the most important and the most widely used spice in the world occupying a position that is supreme and unique. It was the lure of Indian pepper that brought the western world to Indian sub continent.

The black pepper of commerce is the dried mature fruit of the tropical perennial climbing plant Piper nigrum. Pepper originated in the tropical evergreen forests of the Western Ghats. The Malabar coast of India was the centre of pepper trade from time immemorial. Black pepper was essentially a minor forest produce in the past, people collected it from forests where it abundened. Domestication of pepper appears to be a much later event. The recorded history shows that Arabs, followed by the Portuguese, the Dutch and the British traders took pepper to all over the world and spread its use and cultivation. Initially black pepper was taken from the Malabar coast to the Indonesian islands, then it spread to various Pacific islands, South East Asian countries and later to tropical Africa and America. Currently, pepper is grown in about 26 countries, major being India, Indonesia, Brazil, Malaysia and Srilanka. In India, pepper is grown mainly in Kerala, Karnataka, Tamil Nadu and to a little extent in Goa, Orissa, Assam and Andaman group of islands. Kerala is the original home of pepper. This state accounts for 95% of country’s area and production.

Plants that are affected by various abiotic stresses react differently as a result such as the reduction in organ size or a change in the antioxidant enzyme system, and while drought and heat are often studied separately, in nature they often occur together, meaning it is essential to carry out joint studies. Furthermore, and related to the above when we consider high temperature stress, one must always consider the use of water and nutrients by the plant and other physiological functions. The effects of heat stress can also be analyzed by the technique that measures lipid peroxidation in polyunsaturated acids of the plasma membrane. The accumulation of metals in plants, affects the normal processes of plant metabolism. The study shows that there is a relationship between high metal contents in plants and their modified morphology: strong reduction of leaf thickness, modified parenchyma structure, and decreased mitochondria organization were ascertained, although toxic symptoms were apparently absent. Water-deficit stress has a significant effect on plants growth and development, with primary affects on plant structure, leaf morphology and cell ultrastructure. Physiological processes such as stomatal conductance, photosynthesis and respiration are consequently impaired with further implications on the metabolic functions such as carbohydrate and energy production as well as carbohydrate translocation and utilization.

Introduction to GIS

QGIS (Quantum GIS) is an open-source Geographic Information System (GIS) software has been used to showcase various exercises pertaining to viewing, editing, analyzing, and printing of the geospatial data. QGIS helps to allow the users to easily access and manage geographic data stored in folders on local disks or relational databases available on the user’s network. QGIS supports raster, vector, and mesh layers. QGIS also allows using data from external sources with the help of web services such as Web Map Service (WMS) and Web Feature Service. QGIS is a constantly developing software as anyone can add new features or update existing tools. Newer versions of QGIS are frequently released on the official website. It is a cross-platform software that can be installed in Windows, Linux, and MacOS.

13.0 Introduction

Cucurbits belong to the family Cucurbitaceae, commonly known as the melon or gourd family. The term cucurbits was coined by Dr Bailey. From nutritional point of view, cucurbit seeds are valued for their high oil and protein contents. Seed proteins and methionine of cucurbits are higher than legumes. Vegetatively propagated cucurbits are pointed gourd, ivy gourd and chow-chow. Long day of 16 hours and high temperature result in maleness. Short day of 9 hours results in femaleness. They are widely distributed in the tropics and warm temperate regions of south, southeast and East Asia, Africa including Madagascar, and central and south America. Cucurbitaceae family is represented by about 117 genera and 825 species. The most common uses of cucurbits are as vegetables and fruits. They are valuable sources of vitamins and minerals. The important cucurbits that are cultivated commercially are cucumber, watermelon, musk melon, long melon, round melon, bottle gourd, bitter gourd, ash gourd, ridge gourd, sponge gourd, pumpkin, squash, snake gourd, pointed gourd, spine gourd, ivy gourd and chow-chow etc. Cucurbits are used as vegetable, salads, dessert and pickle, and for making of sweets.

Definition of farmer (National Policy for Farmers, 2001): A person actively engaged in the economic and/or livelihood activity of growing crops and producing other primary agricultural commodities and will include all agriculture operational holders, cultivators, agriculture labourers, share croppers, tenants, poultry and livestock rearers, fishers, beekeepers, gardeners, pastoralists, non-corporate planters and planting labours, as well as persons engaged in various farming related occupations such as sericulture, vermiculture, and agroforestry. It also includes tribal families/ persons engaged in shifting cultivation and in the collection, use and sale of minor and non-timber forest produce.

The scientific horticulture consists of the following divisions. Among them, which division has impact on environment aesthetically and functionally

A. Fruits         B. Flowers

C. Spices       D. Plantations

‘Plant disease management’ involves the integration of various measures adopted to protect the plants by preventing them from contact with the pathogenic organisms, preventing the growth of the pathogens causing diseases, preventing sporulation of the pathogens and spread of diseases, destroying insect vectors responsible for transmitting diseases and such other prophylactic and curative measures. The ultimate aim of these measures is to avoid large-scale occurrence of diseases, reduce the severity of diseases and minimizing the losses caused by diseases. In disease management, importance should be given to control all the diseases attacking a particular crop at a particular time, especially those which occur in severe form in all the seasons and cause extensive damage to the crop and yield loss. Each and every crop is subjected to attack by one or more than one diseases. At the same time the control measures for controlling each of the disease may differ. In this respect a knowledge of the pathogen causing the disease, the symptoms of the disease, mode of infection and spread of the disease, the growth stage at which the crop is attacked, interaction between the host (crop) and the pathogen and weather conditions favorable for the occurrence and spread of the disease is absolutely necessary, so as to adopt suitable control measures to combat the disease and to minimize the damage to the crop, and reduce the yield loss.

The occurrence and spread of diseases are very much influenced by the environment, host and the pathogen. When the environmental conditions are suitable for the pathogen and not quite suitable for the host, the incidence of the disease is liable to be more. Further, if the host plants are not maintained properly and are weak, then they are more vulnerable to attack by the pathogen and the disease incidence may be severe. When the inoculum of the pathogen is present abundantly, the chances of attack by the pathogen are also more. Taking these facts into consideration, plant disease management is depicted as ‘manipulation of the disease triangle’ (Fig. 60)

All control measures should be aimed at protecting the plants from becoming diseased and not at curing the plants after they have become diseased. The principal methods adopted for controlling plant diseases are broadly categorized under five different heads viz. :

The livestock sector in India is experiencing fast growth in the present era and plays an important role in the Indian economy. Livestock contributes nearly 25% to the agricultural sector output and growing at an annual rate of 4.3% higher than the growth in agricultural sector as a whole (2.8%). Milk production that had been hovering around 20 million tones in 1960’s increased to 102 million tonnes in 2007-08. The egg production also increased from 0.1 billion to 1.0 billion in the last 25 years. Besides production of milk, meat, etc livestock make important contributions to crop production by supplying draught power and dung manure.

Animal husbandry in India is largely a rural activity. Rapid growth in livestock production is desirable not only to sustain agricultural growth, but also to reduce rural poverty especially when a majority of the land holdings are small. Fifty-eight percent of rural households have land holding of less than 2 ha and another thirty two percent have no access to land. Number of these households is likely to increase due to further fragmentation of land holdings. Livestock are thus an important source of income for small farmers, marginal farmers and landless agricultural labourers in the rural areas of the country. Products like milk and eggs are steady source of cash income, and live animals are important natural assets for the poor, which can be easily liquidated for cash during emergency. Smallholders and landless together control 75% of the country’s livestock resources, and are capable of producing at a lower cost because of availability of sufficient labour with them. These smallholders earn nearly half of their income from livestock sector.

• Pathogen attacks the crop at all stages of crop growth.
• Symptoms appear on leaves, nodes, rachis, and glumes. On the leaves, the lesions appear as small bluish green flecks, which enlarge under moist weather to       form the characteristic spindle shaped spots with grey centre and dark brown margin (Leaf blast).

The entrepreneur as a person brings in overall change through, innovationfor the maximum social good. Human values remain sacred and inspire him to serve society. He has firm belief in social betterment and he carries out this responsibility with conviction. In this process, he accelerates personal, economic as well as human- development.

The potential for significant economic losses from decay caused by postharvest pathogens is greater than is often realized. Harvesting and handling, and the attendant costs for labor and postharvest chemical treatments, can increase the cost of fresh fruits and vegetables several fold from the field to the consumer. Therefore, any produce lost in storage is worth more economically than an equivalent amount lost in the field. Considering economics and the problem of world hunger, it is imperative to understand the importance of postharvest disease and to continually strive to reduce postharvest losses from pathogens. In recent years, many international organizations have identified the necessity of reducing postharvest food losses as an important worldwide goal. While postharvest losses vary from season to season, an average loss of 10% to 30% after harvest is an average estimate. Significantly higher losses are not uncommon in developing countries. The extent of these losses justifies increased research efforts in postharvest pathology (Carl E. Sams, 1994). Chemical treatments and irradiation have effectively reduced the number of microorganisms on various commodities. However, consumer fears associated with chemical residues and the effects of ionizing radiation on fresh produce are forcing the development of alternative protection methods. Also, many pathogens have developed resistance to several commonly used chemicals, while other decaycausing microorganisms currently cannot be controlled by chemicals. Therefore it is better to seek control strategies that will supplement or replace current disease control methods.