eChapters

23.1. What?

Post harvest and agro-processing refers to activities carried out after harvesting a crop. These include milling, grading, processing and packing of the produce before it reaches the end users. This is also referred to as value addition, as it increases the marketable quality of the harvested produce.

23.2. Milling

It is the process of separating edible portion of the grain after removal of the husk or seed coat. This converts the products into a form that can be readily used for cooking, e.g. rice milling and dal milling.

23.3. Grading

Grading is the process of segregating the harvested produce based on the physical appearance including size and colour. Grading increases the market value of the crop.

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.

Fruits, nuts and vegetables play a significant role in human nutrition, especially as sources of vitamins, minerals, dietary fibre, and antioxidants. Increased consumption of a variety of fruits and vegetables on a daily basis is highly recommended because of associated health benefits, which include reduced risk of some forms of cancer, heart disease, stroke, and other chronic diseases. Both quantitative and qualitative losses occur in horticultural commodities between harvest and consumption. Qualitative losses, such as loss in edibility, nutritional quality, caloric value, and consumer acceptability of fresh produce, are much more difficult to assess than are quantitative losses. Quality standards, consumer preferences and purchasing power vary greatly across countries and cultures and these differences influence marketability and the magnitude of postharvest losses. Postharvest losses vary greatly across commodity types, with production areas and the season of production. Losses of fresh fruits and vegetables in developed countries are estimated to range from 2 percent for potatoes to 23 percent for strawberries, with an overall average of 12 percent losses between production and consumption sites. In contrast, the range of produce losses in developing countries varies widely. Losses at the retail, food-service, and consumer levels are estimated at approximately 20 percent in developed countries and about 10 percent in developing countries (Adel A. Kader and Rosa S. Rolle, 2004 ). Overall, about one third of horticultural crops produced are never consumed by humans. Reduction of postharvest losses can increase food availability to the growing world population, decrease the area needed for production, and conserve natural resources. Strategies for loss prevention include use of genotypes that have longer postharvest-life, use of integrated crop management systems and good agricultural practices that result in good keeping quality of the commodity and use of proper postharvest handling practices in order to maintain the quality and safety of fresh produce.

1. INTRODUCTION

Fruits and Vegetables are heighly perishable crops and have to be handled carefully after harvest. Postharvest handling of these perishables is essential to prevent the post harvest losses and maintain the quality of the fruits and vegetables. Various treatments (chemical, physical and biological agents) have been standardised and used for retaining the storage quality of different horticultural commodities. All these aspects have been discussed in this chapter.

1. INTRODUCTION

In the changing global scenario, food nutrition, health care and livelihood security are the matter of great concern to human, social and economic development. Fruits and vegetables is one of the most important and fast growing sub-sectors as they form an indispensable part of healthy diet. The current trend shows that dietary habits are changing with increasing income, from cereal based diet to nutritious diet. Resultantly, there is a growing demand for horticultural produce.

World production of vegetables amounts to 1169.45 million tonnes, while that of fruits is 689.39 million tonnes (NHB, 2017). India is the second major producer of fruits and vegetables in the world and ranks next to China. India produces 92.85 million tonnes of fruits from an area of 6.5 million hectares and 175.00 millions tonns of vegetables from an area of 9.2 million hectares annually. The productivity of vegetables in India is 17.6 tonnes per hectare. Potato (28.9%), tomato (11.3%), onion (10.3%) and brinjal (8.1%) are the 4 major vegetables contributing 58.6% of total vegetable production in our country. Other important vegetables are cabbage (5.4%), cauliflower (4.6%), okra (3.9%) and peas (2.4%)

1. INTRODUCTION

India produces a large variety of fruits and vegetable due to varied agro-climatic conditions. These include mango, citrus, banana, apple grapes, strawberry, pineapple, litchi, guava, papaya, plum, peach, pear apricot etc. Astonishingly, it may appear but it is a fact that postharvest losses of fruits and vegetables in India are staggering. Infact the postharvest losses of fruits and vegetables are equivalent to the annual consumption of fruits and vegetables in U.K. In this article, a focus is made on the causes of postharvest losses of fruits, overview of various techniques used to prevent the postharvest losses constrains in postharvest technology and future strategies.

Postharvest food loss has been considered an unavoidable affliction since food storage first began. These losses are much more painful and costlier in terms of money and man-hours. Such losses due to plant parasitic nematodes, in particular, is severe in tropical regions especially in developing countries like India, where proper storage, transmit and marketing facilities are inadequate. In tropical agriculture, increase in production rate is generally low and, by itself, unable to keep pace with the requirements of the increasing population. Hence, such food shortage demands the need to reduce postharvest loss due to nematodes. Postharvest food losses also constitute a vast complex of physical and biological changes, which makes it very difficult to represent in a single figure. As suggested by different sources, an overall loss of at least 10 per cent occurs in the developing countries. However, the magnitude may range from negligible to cent percent in particular nematode species and crop.

In addition to causing direct losses individually, phytonematodes also favour the establishment of secondary, passive micro- organisms like fungi, bacteria, viruses etc. Nematodes cause mechanical wounds, which serve as avenue for the entry of secondary microorganisms (Ravichandra, 2008). This complex association results in severe damage to planting material.

Postharvest diseases due to nematodes can be managed through restricting the movement of infected planting material to uninfected areas; use of uninfected, healthy planting materials; use of treated planting materials; improvements in the cultural practices at the growing site; timely and careful harvesting; use of nematicides both at pre- and postharvest stages; employment of some physical means like heat, radiation etc; improved storage techniques and integration of these methods. By maintaining hygienic conditions during harvest, transportation, storage and packing most of the postharvest damage due to nematodes can be minimized. Of all the methods, however, regulatory measures like quarantine is more practical and effective in restricting the movement of nematode infected plant materials and contaminated soil into a state or country. Contaminated plant material should be treated (hot water or nematicides) to kill the plant parasitic nematodes before planting to prevent the further postharvest damage. These various measures are primarily aimed at either reduction or wiping out of stages of nematode from the site or protection of host from infection or creation of unfavorable host and/or environmental conditions for the nematodes.

Pomegranate is one of the oldest known edible fruits and is associated with ancient civilizations of the Middle East. From its origin in the area now occupied by Iran and Afghanistan, the pomegranate spread east to India and China and west to Mediterranean countries (Turkey, Egypt, Tunisia, Morocco, and Spain). Spanish missionaries brought the pomegranate to the Americas in the 1500s (Hodgson, 1917; LaRue, 1980). The primary commercial pomegranate growing regions of the world are the Near East, India and surrounding countries, and southern Europe. The fruit is consumed fresh or processed into juice, syrup, jams, or wine (Fig. 1) (LaRue, 1980; Adsule and Patil, 1995; Kumar, 1990; Patil and Karale, 2001; Roy and Wasker, 1997).

1. GENERAL INFORMATION

India’s exports of Processed Food was Rs. 31563.43 Crores in 2014-15, which includes products like Mango pulp (Rs. 841.39 Crores), Dried and Preserved vegetable (Rs. 847.11 Crores), Other Processed Fruit and Vegetable (Rs. 2,569.93 Crores), Pulses (Rs. 1,209.51 Crores), Groundnuts (Rs. 4,675.35 Crores), Guargum (Rs. 9,480.00 Crores), Jaggery and Confectionary (Rs. 1,161.81 Crores), Cocoa Products (Rs. 848.62 Crores), Cereal Preparations (Rs. 3,038.79 Crores), Alcoholic and Non-Alcoholic Beverages (Rs. 2,231.58 Crores) and Miscellaneous Preparations (Rs. 2,437.77 Crores).

Ornamental pot plants should be potted in small pots according to the size of the plants. Any kind of pot/container which can hold medium and provide aeration is suitable. The most common container is the plastic or clay pots. Plastic pots should be preferred because it retains moisture longer than mud pots. Plants should not be disturbed frequently and re-potting done only when absolutely necessary.

Potting media

Different types of growing media may be used for ornamental pot plant cultivation, but it is crucial that it must retain a certain amount of moisture and be well draining. Different plants require different substrate in which they would thrive. Conditions of the plant experiences in nature should think before choosing the media. Tropical plants require more water naturally compare to subtropical and temperate ones. For irrigating with sprinkling can or hose, it is better to use materials that drain well and decompose slowly while for drip irrigation heavy potting material should be used. The most important thing is to match watering habits to the potting material. Growing conditions play a most significant role in deciding on a medium. If there is no problem in providing a constantly humid environment due to climate or if growing in a greenhouse, the moisture retention on thepart of media is less of a concern. Ambient temperatures play a role here, as well, as warmer temperatures tend to increase the evaporation of water and along with the drying rate of the medium. The personal tendencies and how much time might be spending to water plants is another significant factor in choosing a medium. The combination of potting materials that will work best for garden plants mainly on Plant structure and root structures:

Abstract: Calendulas, popularly known as pot marigold, are admired for their ornamental value. The leaves, seeds and flowers are source of oil, pigments, dye, flavonoids, and ingredient in cosmetics, human, and animal medicines and dietary composition. Currently, there are intraspecific hybrids in the market. Traits of interest to flower breeders for crop transformation include plant architecture, flowering, flower colour and size, large and bold seed with high oil, pest and virus resistance.

Keywords: Calendula, intraspecific hybridization, mutation, molecular marker.

Abstract

Quality of water is a matter of serious concern for arid and semi arid region like Rajasthan. The study area chosen is extreme western arid part of Rajasthan state where water quality and quantity both are very important issues. Due to absence of any perennial river, scanty rainfall and scarcity of surface water resources, ground water is very deep and saline. The groundwater potability assessment was based on 1119 wells water quality data. The purposes of this investigation were (1) to provide an overview of present groundwater quality and (2) to determine spatial distribution of groundwater quality parameters which affect water potability and (3) to map groundwater potability in the study area by using GIS and Geostatistics techniques. Arc GIS 9.3 and Arc GIS Geostatistical Analyst were used for generation of various thematic maps and Arc GIS Spatial Analyst to produce the final groundwater potability map.

Potassium is the third important essential nutrient element after nitrogen (N) and phosphorus (P) required by all living organisms, including plants and animals. Potassium is essential for many metabolic activities like carbohydrate metabolism, nitrogen metabolism. It is required for the activation of over 60 enzymes in plants. It controls/regulates the activities of various essential nutrients. It is vital to photosynthesis, and synthesis of carbohydrates, starch and proteins in plants. It plays vital role in controlling the opening and closing of stomata in photosynthesis. It also helps in controlling water use by plants by regulating the osmotic pressure of guard cells during transpiration. It plays a major role in transport of water and nutrients throughout the plant in xylem. Potassium improves crop yield and quality of flowers, fruits, vegetables and other field crops in terms of size, shape, colour, taste, shelf-life, and fibre quality. Potassium stimulates the growth of strong stems and provides strength to the plant against some disease by promoting thickness of the outer cell walls. It is required for translocation of assimilates. Under reduced K supply, translocation of NO₃^-, PO₄^3-, Ca²⁺, Mg²⁺ and amino acids is hampered. It also imparts resistance against environmental stresses such as drought, cold and frost. Adequate K can reduce moisture loss from growing plants, thereby giving some drought resistance. It reduces lodging of crops and enhances their winter-hardiness.

It is taken up by the plants as K⁺. Being a basic element, it takes part in neutralization of the acidity in plants caused by several organic acids produced. It does not form organic compounds in the plant system. It is the most mobile element in the plant. Thus, it can move through all the plant system due to osmotic pressure. When any plant sample is dipped into water, some K comes out. This shows that it is highly mobile.

Potassium is also required for animal nutrition and human beings. Potassium is essential for many metabolic functions. It maintains salt balance between cells and body fluids. Adequate K is essential for nerve function and preventing muscle cramps. It is routinely added to many animal feeds. Since K⁺ is not stored in the human body, dietary replacement is required on a regular basis. Government agencies state that diets containing foods that are good sources of K and low in Na may reduce the risk of high blood pressure and stroke.

16.1. Forms of Soil K

Ignoring potassium (K) in soil organism, total K in soil may be classified as (i) water soluble K, (ii) readily exchangeable K (exchangeable K), (iii) slowly exchangeable K (non- exchangeable or fixed K) and (iv) mineral or lattice K. The different forms are in dynamic equilibrium with one another.

23.1 Forms of Soil K

Ignoring potassium (K) in soilorganism, total K in soilmaybe classified as (i) water soluble K, (ii) readily exchangeable K (exchangeable K), (iii) slowly exchangeable K (non- exchangeable or fixedK) and (iv) mineral or lattice K. Thedifferentforms are in dynamic equilibrium with one another.

Potassium is an important plant nutrient that influences water relations, carbohydrate and nitrogen metabolism, crop quality and resistance to environmental stresses. This chapter examines potassium behaviour and management in irrigated soils. It begins with the functions of potassium and explains the different forms in which potassium occurs in soil, including relatively unavailable, slowly available and readily available forms. Potassium fixation and release are discussed in relation to soil colloids, temperature, drying, soil pH and aeration. These processes determine the amount of potassium available for plant uptake and are particularly important in intensively cultivated irrigated soils. The chapter also considers luxury consumption and interactions between potassium and other elements. Potassium management is discussed through appropriate rates and methods of application and selection of suitable potassic fertilizers. The effects of potassium nutrition on plant behaviour, water utilization, carbohydrate and nitrogen metabolism, crop quality, disease resistance and low-temperature injury are highlighted. The chapter therefore provides a framework for maintaining potassium availability and preventing nutrient depletion in productive irrigated

Abstract

Potassium is a very essential nutrient element that is required for proper health, growth, functioning and productivity of plants. However, up to 98% of this very important mineral is held up in insoluble, unavailable forms in the soil and with only approximately 2% soluble form available for plant use. Biofertilizers add nutrients to the soil for plant use by some mechanisms like the breakdown of phosphorus, potassium, fixing nitrogen, and also synthesizing some substances which in turn enhance plant growth. These processes take place naturally. Microorganisms that solubilize potassium have demonstrated an increased potassium uptake by plants when added as bio-inoculants consequently resulting in increased yield by these plants. This article reviewed the methods of isolation of potassium solubilizing bacteria and fungi and their use as biofertilizers. Data are presented showing summary of researches conducted on potassium solubilizing microorganisms and their findings. Figures on production efforts of biofertilizers in India per year and by states are also added.

Potassium (K) is among the most important essential macronutrients for plant growth. About 98% of the potassium in the earth’s crust exists in insoluble forms as rocks and silicate minerals, resulting in very low concentrations of soluble potassium in the soil for plant growth and development. Potassium is never incorporated in any organic compound and even in the plant system it remains as K⁺ ion. It does not form any gas that could be lost to the atmosphere. It does not cause eutrophication. When left in the ecosystem as such, it is not at all toxic.Potassium activates enzymes, maintains cell turgor, enhances photosynthesis, reduces respiration, helps in transport of sugars and starches, and is essential for protein synthesis. In addition to plant metabolism, potassium improves crop quality because it helps in grain filling and kernel weight, strengthens straw, increases disease resistance and helps the plant better to withstand stress.

Potassium in Soils

Soils usually contain potassium in larger amounts than any other nutrients. Total K content in soil is 30,000- 50,000 kg/ha in top layer of the soil. Nearly 98 % of K bound in the mineral form and 2 % is in soil solution. Generally, potassium in soils exist in four forms (often called fractions), their availability to crop roots is considerably different.

Glauber J. R. (1604–1670) in Netherlands first proposed that the salt peter (KNO₃) was the principle of vegetation. He obtained large increases in crop yield by addition of salt peter.

Mineral soils contain 0.04–3.0% K. Total potassium content of soils range from 3000 to 100000 kg per ha in the upper 0.2 m of soil profile. Of this total potassium approximately 98 percent is bound in mineral form whereas 2% in soil solution and exchangeable phases.

ROLE OF POTASSIUM

It is Involved in activating the enzymes (as many as 80) responsible for carbon dioxide reduction and required for synthesis of adenosine triphosphate. Hence deficiency of potassium reduces crop growth and yields.

Potato, the third most important food crop in the world after rice and wheat is becoming the main source of food and income in developing countries. India stands second in production and area of potato in world after China leaving behind the Russian Federation. In India, potato is an important component in cereal and vegetable-based cropping systems for its ability to produce high dry matter/ha in short duration and high yield compared to cereals. It is grown as mixed crop, intercrop, relay or sequential crop along with other vegetables, cereals and cash crops.

Potato is originated in South America in the high Andean hills and towards the end of 16th century it was first introduced into Europe by Spanish conquerors. In the early 17th century, it was brought to India by British missionaries or Portuguese traders. Thus, potato developed as a temperate crop and was later distributed throughout the world. Cultivated potato consists of two sub species, Solanum tuberosm ssp. andigena and S. tuberosum ssp tuberosum. Subspecies andigena is the primitive form which is adapted to shorter day length and high altitudes of mountains (above 2000). The presently cultivating tuberosum subspecies is adapted to long or short day condition of tropical regions and lower altitudes (500-200m above MSL) and is believed to be evolved from andigena types through selection.

Morphology and Floral Biology

Potato is herbaceous in nature with erect to prostrate stem. Stem is variably coloured from green, purple or mottled green or purple. Leaves are pinnate which ends in single terminal leaflet. Stolon arise from the portion of the plant below the ground. The stolon bears rudimentary leaves and tip is hook shaped. The sub apical portion at the tip of stolon enlarges to produce tubers. Hence, potato tubers are the modification of underground stem with shortened axis and poorly developed eyes. The leaf scar with a subtended lateral bud having underdeveloped internodes is referred to as the eye of the tuber. Potato is a long day plant. Moderate humidity and long day condition favours flowering. Hence flowering and fruit set is observed in hilly tracts. Inflorescence is produced terminally and is usually cymose. Flowers are bisexual, actinomorphic, and hypogynous with 5 calyx, 5 corolla and 5 stamens. The colour of corolla varies from white, pink, lilac, blue and purple. Pollen shedding is through the pores at the tip of the anthers. Mature fruit is a berry. Self-incompatibility is observed in diploid species and tetraploids are self-compatible.