Preface Being at the forefront among the national agricultural discipline, horticulture has played its major role in ensuring food and nutritional security of the country. They are not only delicious and refreshing but are also the chief source of vitamins, minerals and proteins. The book is primarily meant for the student of graduate and postgraduate in the field of horticulture of all agricultural universities in India and neighbouring countries. The information included in this book is considered to be of utmost value to student of horticulture fruit & vegetable growers, nursery man, gardeners, subject matter specialist and other person’s engaged in the field of horticulture. In this edition I have shared my personal experience on horticultural crops acquired during last nineteen year. The book will proved boon for student contesting Indian Council of Agricultural Research Junior and Senior Fellowship, Agriculture Research Services examination and NET in the field of horticulture. I am highly thankful to management of the college and principal for providing me always moral support in writing of this book. We have great pleasure in acknowledging moral support, encouragement valuable suggestion and connective criticism received from Dr. Hari Baksh, Mr. Raj Pandey and all agriculture faculty members, Tilak Dhari P.G. College, Jaunpur. I am highly grateful to Prof. Anil K. Singh (BHU), Prof. Ranveer Singh, Prof. J.P. Tiwari and Prof. Hari Har Ram who always encouraging me for preparing this manuscript. We appreciate the efforts of Mr. Sumit Pal Jain, M/s. New India Publishing Agency, New Delhi for printing the book in the nice form. We fill immense pleasure to express our heartfelt gratitude to my elder brother Prof. I.S. Singh, Mr. Avaneesh Singh and all family members who always inspiring, guidance, encouragement and blessing.

The term ‘Horticulture’ is derived from two Latin words, Hortus meaning Garden and Cultura meaning Cultivation. In ancient days the gardens had protected enclosures with high walls or similar structures surrounding the houses. The enclosed places were used to grow fruits, vegetables, flowers and ornamental plants. Horticulture differs from agriculture and forestry in specializing the cultivation of garden crops. The garden crops include fruits, vegetables, flowers, ornamental trees, spices, plantations, medicinal and aromatic plants. Horticultural crops do not give food grains. The products of horticultural crops such as fruits and vegetables are highly perishable so that they are utilized in the fresh state. In general horticultural crops need more intensive cultivation (i.e. need more work) than the agricultural crops. Special Features of Horticulture As horticultural crops generally need intensive cultivation, they require a large input, capital, labour and technology per unit area of land. Many cultural operations are specific to horticultural crops. The cultural operations such as propagation, fertilization, training, pruning, harvesting and marketing are skilled operations and these are specific to horticultural crops. Mostly the horticultural products are utilized in the fresh state and are highly perishable. Most of the horticultural crops are the rich sources of vitamins and minerals. Gratification or aesthetic sense is an exclusive phenomenon for horticultural science.

Horticulture means the cultivation of garden plants. The garden plants are comprised of fruits, vegetables, ornamentals etc. The culture covers the operation from raising and planting of saplings to the ultimate use of the products and, as such, it is the most intensive of all the agricultural sciences. However, the concept of growing plants in garden or in an enclosure does not fit well in the changed perspective where large scale cultivation of fruits, vegetables and flowers extending over several square kilometers, in many a place nowadays, delimits the boundary of garden. Importance of Horticulture The importances of horticulture are established not only as a source of nutritious foods but also in many other ways which are narrated in the following points: Social- Due to the long association, the fruits are seen to have a permanent seat in the social life of man. As a consequence, various fruits have acquired their place in art, music, literature, customs and habits of various nations of the world. The description of fruit as symbolic insertion in the poems and literatures, the use of whole fruit plant or part thereof in various social festive and public gathering, and conferring titles to individuals in the name of fruits or naming a region or whole district after the name of a fruit are nothing but an indication of their popularities and social position in various countries.

Fruits and vegetables play an important role in balanced diet. These provide not only energy rich food but also provide vital protective nutrients/elements and vitamins. Comparatively fruits and vegetables are the cheapest source of natural nutritive foods. Since most of Indians are vegetarians, the incorporation of horticulture produce in daily diet is essential for good health. Realizing the worth of fruits and vegetables in human health, Indian Council of Medical Research (ICMR) recommended the use of 120g fruits and 300g vegetables per capita per day. With the growing awareness and inclination towards vegetarianism worldwide the horticulture crops are gaining tremendous importance. Functions of fruits and vegetables in human body Fruits and vegetables provide palatability/taste. Improves appetite and provides fiber to overcome constipation. They neutralize the acids produced during digestion of proteins and fatty acids. They improve the general immunity of human body against diseases, deficiencies etc. They are the important source of vitamins and minerals for used in several bio-chemical reactions occur in body.

Classification is system of placing an individual or a member in various groups or to categories them according to particular plan or sequence which is in conformity with the nomenclature. From time-to-time for purposes of convenience plants or fruits have been classified in various ways that makes possible to refer them to a large number of kinds under a group name without enumerating or specifying individually. The basis of these groupings varies according to the features of fruits or growth of the fruit plants that have been under classification at the time. Knowledge of classification of horticultural plants is very useful to the horticulturists because it serves: (1) to identity and name them, (2) to afford at least some idea of the closeness of their relationship i.e. line of descent to other kinds, (3) to suggest with what other kind they possibly may or may not be interbred or crossed, (4) to suggest the kinds with which they possibly may or may not be inter-grafted, and (5) often to suggest certain soil and the cultural requirements, climatic adaptations etc. However, the classification of fruit trees or fruits and vegetables on the basis of consumer’s rating also gained attention in recent years. The consumers’ rating is mainly based on the size, shape, nutritive value and marketability of them. Each of these classifications is quite different from the other classification or groupings. Basically, the fruit trees, as suggested by many authors, have been classified on the basis of their botany comprising of taxonomic ancestry, morphologic features, physiological functions, adaptability etc. or on the basis of agricultural and horticultural requirements. But the consumers’ rating has not been properly covered in the earlier classification. Generally based on botanical relationship the plants are classified as under.

Soil- Soil is the upper most crust of earth surface which supports plant growth. It is defined as a three phase system in which plants grow. These phases are solid, liquid and gas and are essential. Solid part is frame which provides space for other two. This consists of minerals, clay minerals and organic matter. The soil is also a living system with millions of microbes that breakdown organic matter and builds it again. Some points are following Microbes are essential and survive only when soil is well aerated and rich in organic matter and devoid of waterlogged conditions. Texture of soil depends on the size of solid particles and classified as gravel, coarse and fine sand, silt and clay. Soils are classified according to relative distribution of these particles and there are 12 textural classes. Likewise, arrangement of these particles is referred as structure, and both texture and structure lend soil physical properties like water holding capacity, aeration and bulk density. Generally loamy soils and crumb structure are most preferred for fruit crops. According to level of organic matter, soils are classified as mineral soil or organic soil and soil having more than 20% organic matter is organic soil like peat and muck.

Water Water is one of the most important inputs essential for the production of crops. Plants need it continuously during their life and in huge quantities. It profoundly influences photosynthesis, respiration, absorption, translocation and utilization of mineral nutrients etc. Both its shortage and excess affects the growth and development of a plant directly and consequently its yield and quality. Soil needs the application of water to: Remove stress condition. Release nutrients in the soil solution for absorption by plants. Leach or wash out injurious salts from the soil. Preparation of land for raising crops. To maintain the temperature and humidity of the soil micro-climate and the activity of soil microbes at optimum level. For the normal aeration and functioning of roots and shoots of the plants. Excess water needs to be removed for the normal aeration and functioning of roots and shoots of the plants Excess water creates unworkable soil condition.

Nutrients The nutrients are chemical elements which are absorbed by the plants in more or less quantity to transform light energy into chemical energy and to keep up plant metabolism for the synthesis of organic materials. These materials constitute among other things, foods for humans and animals and a range of raw materials for various industrial uses. Feeding of plants with nutrients is termed as nutrition. Successful growth and production of the plants in general requires a proper supply of the 17 elements. These elements are regarded as essential to life in higher plants.

Weed Weed in orchards reduce crop yields by competing for moisture, nutrients, light and space. They also harbour insect pests and diseases. When they become large they interfere with orchard operations. Some of weeds climb on the trees and shade the foliage. There are some weeds which are parasitic partially or completely on the host tree e.g. Striga and loranthes on mango.

Mulching It means covering of soil surface by some organic or inorganic materials for conserving the soil moisture besides covering on the soil moisture several other advantage of mulching. The materials which are used in mulching called mulch.

Nursery Nursery is a place where seedling, saplings or any other planting materials are raised, propagated, multiplied and sold out for planting. The prerequisites of a successful and remunerative fruit production are the availability of true-to-type, healthy and good quality planting materials. Setting up of a fruit nursery is a long term venture and requires careful planning and expertise, because mistakes committed initially cannot be rectified easily and may adversely affect the return from the investment. Thus, one should pay due attention on every aspects when nursery is to be established.

Propagation Plant propagation means multiplication of plant by sexual or asexual method. The success in plant propagation depends on a thorough knowledge of the growth of plants, choice of suitable method and technical skill. The propagation of plants may be done either by the gametes or from the somatic cell, tissues or organs. In other words, propagation may be done by sexual methods or by asexual methods. The details of the methods are presented below.

Orchard Establishment of orchard is a long term investment. It is require a proper planning, any mistake during the selection of site, planting distance, choice of crop/variety, quality of nursery stock etc. reflect greatly on the orchard performance and efficiency.

Planting System Main objective of layout is maximum number of plant accommodated in per unit area without affecting the efficiency of production. If more than one fruit is included in the orchard plan, each kind should be grouped into individual block. Similarly fruit ripened in particular season should be grouped to facilitate convenience in watch and ward, harvest and post harvest handling. Some kind of fruit trees need pollinators/pollinisers for improving the fruit set.

Horticultural plants are grown for their produce like fruit, vegetable, flower, medicinal component, spices etc. Therefore, these plants should be managed in such a way that human desires for the purpose of growing them are fully satisfied in terms of quality and quantity of produce. This demands direct manipulation of plant growth itself or plant environment through various inputs. In manipulation of plant development, training and pruning are important for which our knowledge about plant development and its phenology has to be complete. These practices are important in fruit crops.

Bearing Bearing is connotation of flowering and fruiting. When a fruit tree flowers and fruits, it is said in bearing condition. Different fruits have different bearing habits, inflorescences, types of flower, mode and medium of pollination, pollen viability and all these account a lot for the bearing of fruit plants. Bearing habit If one observes a mango tree, he/she may find it does produce the fruits terminally on a shoot and it citrus he/she finds the fruits always produced laterally in the leaf axils. The manner or patter in which a plant produces its fruit is known as bearing habit or fruiting habit. Bearing habits are specific to the kind of plant. In determining the bearing habit of any plant three points are to be considered.

The quantitative increase in plant body such as increase in the length of stem and root, the number of leaves etc., is referred to as plant growth whereas, the qualitative changes such as germination of seed, formation of leaves, flowers and fruits, falling of leaves and fruits is referred as development. Utilization of these substances for proper development of the plant is regulated by certain chemical messengers called plant growth substances or plant growth regulators, which in minute amounts increase or decrease or modifies the physiological process in plants. Plant growth substances are the chemical other than nutrient which required in very small amount but without which plant can not complete their physiology. The two sets of internal factors, viz., nutrition and hormone control the growth and development of the plant. The raw material required for growth is supplied by nutritional factors which include the minerals, organic substances the protein, carbohydrates, etc. Phytohormones: These are the hormones produced by plants which in low concentrations regulate plant physiological process. These usually move within the plants from a site of production to a site of action. Plant growth regulators: These are organic compounds other than nutrients, which in small amounts promote, inhibit or otherwise modify any physiological process in plant. It may be defined as any organic compounds which are active at low concentrations (1-10 ml) in promoting, inhibiting or modifying growth and development in plants. The naturally occurring (endogenous) growth substances are commonly known as plant hormones, while the synthetic ones are called growth regulators. Plant hormones: It is an organic compound synthesized in one part of plant and translocated to other parts, wherein very low concentration causes a physiological response. The plant hormones are identified as promoters (auxins, gibberellin, and cytokinins), inhibitors (abscisic acid and ethylene) and other hypothetical growth substances (Florigen, death hormone, etc.).

The current status of advances in fruit breeding is through the development of different scientific approaches augmented by ever-increasing knowledge and application of genetics, statistics and biotechnology. These innovative approaches very specific for a species in most of the cases, are the major tools of the fruit breeders to tackle the different objectives of fruit improvement programme at present Fruit improvement is a very slow process due to the long generation cycle varying from species to species, thereby reducing the chances of exploiting genetic recombination. Besides this factor, most of the fruit species are either highly heterozygous or polyploidy in nature. Due to this reason the asexual propagation of fruit plants is a conventional means while wide segregation occurs upon sexual reproduction. Such expectation is not unlikely because the types selected as commercial varieties are definitely to be vigorous ones, and a positive correlation exists between vigour and heterozygosity. This discussion on breeding of fruit plants involves different aspect of the species concerned is so essential as well as fundamental that discussion of them must procede any consideration of breeding methods themselves. The plant species are grouped into two-self-pollinated and cross-pollinated. These two groups have emerged on the basis of pollination mechanism which plays significant role in the method of breeding application. To emphasize the difference in the reproductive systems of these two groups one should know the details about floral biology, mechanism of pollination control, reproduction by asexual and sexual means and self and cross-pollinated plants.

Physiological disorders are abnormalities in plants which are associated to non-pathogenic factors. A plant or its parts may show unusual growth, function or deformity. Such abnormalities are widely referred to as disorders. These may be incited by nutrients deficiency or excess, hormonal imbalance, abnormal growing conditions etc. Some commonly observed disorders have been dealt in here suitably.

Seedlings of several vegetables are first raised in well prepared nursery beds, followed by transplanting in the field. Raising of seedling in the nursery beds is economical as well as easier to take care of young, tender seedlings against pest and diseases. Further, raising of seedlings in nursery allow more time for land preparation. Site and soil for nursery In selecting a site for nursery beds, following points should be considered viz sunny situation, good drainage and irrigation facilities. Sandy loam soil with plenty of organic matter are ideal for starting nursery beds. In case of heavy soils it is desirable to add coarse sand to modify the soil condition. Before sowing seed it is essential to sterlize the beds by steam or formaldehyde or any other chemical to do away with problem of damping-off disease. Burning of leaves or straw in the beds is quite helpful in controlling certain soil borne diseases and pests.

Seed A seed is a mature ovule consisting of an embryo together with stored food, all enclosed by a protective coat. It is product of the ripened ovule of gymnosperm and angiosperm plants which results as a consequence of fertilization and some growth within the mother plant formation of seed completes the cycle of reproduction. The embryo develops from zygote and the seed coat from the integument of ovule. A seed has three main parts these are seed coat, endosperm and embryo. Embryo includes the root, the cotyledon and embryonic leaves. Seed is located inside fruit and a fruit is a mature ovary. In broad sense any plant part which is used for commercial multiplication of crop is called seed. Thus in case of potato stem and tuber are also known as seed. Improved seed results in (1) Better germination (2) Vigorous seedling growth (3) Higher crop stand (4) Better quality of produce (5) Ultimately in higher crop yield. Development of seeds: Successful pollination and fertilization are the prerequisites to produce a viable seed. During pollination the pollen grains are transferred from anther to the stigma and get stuck there in the sticky fluid secreted by the stigma. The fluid contains sugar which induces germination of pollen grains. The pollen tube grows downward through the style in the ovary until it reaches the embryo sac and discharges two male gametes-one is fused with a female gamete and forms the zygote (2n) and the other is united with two pollar nuclei to produce endosperm (3n). The zygote develops and gives rise to embryo embedded in nutritive tissue developed from endosperm. The nucellus tissues surrounding these structures provide necessary energy for their proper development. Like fruit, the seed also exhibits sigmoid and sometimes double sigmoid pattern of growth. Various changes occur during the course of seed development and the sequences of development may vary from species to species keeping the basic theme unaltered.

The purpose and the mode of marketing of vegetables determine the type of vegetable gardening. The various types of vegetable gardening are as follows. Home or Kitchen gardening Market gardening Truck gardening Processing gardening Vegetable forcing Seed production gardening Floating vegetable gardening

Vegetable crops: A seed is borne on fruit and fruit is a mature ovary and ovary is a typical part of flower. Flower in angiosperm, consists of four parts these are calyx/sepal, corolla/petals, androecium/stamens and gynocium/pistil, outer whorl of flower is collectively referred to as calyx. The individual components of calyx are called as sepal. Petals are collectively referred to as corolla. Petal is a unit of second inner whorl after sepals. Stamen is part of flower bearing the male reproductive parts composed of anther and filaments. Pistil is part of flower bearing the female reproductive parts composed of stigma style and ovary. Seed Production Techniques in Vegetable Crops Share (%) of F1 hybrids- Cabbage 85%, Watermelon 70%, Okra 23%, Tomato 80%, Chilli 80%, Cauliflower 50%. Among the Asian countries, India is the 2nd largest production of hand pollinated hybrid seed in vegetables.

The planning of a garden is an art. It is said that a poet is born, and in that sense a garden architect is also born. But that does not mean that a garden architect has nothing to learn. On the contrary he should learn enough of geology, geography, garden history, styles of gardening, and above all should have a profound knowledge about plants. It is imperative to know at the outset what is meant by landscape gardening. A landscape may be defined as any area, either big or small, on which it is possible or desirable to mould view or a design, whereas landscape gardening may be described as the application of garden forms, methods, and materials with a view to improving the landscape. The art of designing is known as “landscape architecture,” although the older term landscape gardening” is also popular. Before discussing the principles of gardening in detail, it will be worthwhile to make some useful suggestions. The first and the foremost thing are not to imitate another garden which has secured a prize in a competition. One has to develop one’s own design giving due consideration to the local conditions. One more mistake which is commonly made is to plant many more specimens than a garden can accommodate causing overcrowding. In a landscape garden any difference in levels has to be taken advantage of, but in a perfectly flat land it will be costly to create artificial undulations. In each garden the care should be at least one feature or there be a second these two should harmonize with each other. Before planning a design are must be sure for what purpose the garden is utility or beauty or both.

Lawn Lawn is a natural green carpet, and it is important feature of a landscape and a garden without a lawn is not considerd complete. Lawn is an area of land closed mowed grasses it is primarily developed for aesthetic and recreational purpose. A lawn is an integral part of a garden and landscape besides aesthetic and recreational purpose and several other purposes. Lawn provides a place for taking rest after tiring of the day, holding parties, social functions, passive and active recreation. Distinguishing characteristic of turf grasses is the ability to with stand close mowing and still providing a functional dense healthy ground cover. Lawn is also called as heart of garden. Lawn can be called as turf pitch a field, sod, yard, are green depending upon the plantation usage continent. Lawn is a ground cover of perennial grass, ditch, persists enclose mowing and require proper management practice. J.B. Olcoth designed first experiment in lawn grass at Monchester in USA in the 19th century. Festuca and Agrostis species were used to make turf (Lawn) during 1880 in U.K. In the early 19th century lawn become wild spread out side of parks golf course. Now a day in many metro cities of India lawn has become a cultural of the passion of many homes.

Garden Garden is a place where vegetables, fruits and ornamental plants are grown mainly for recreation. The garden incorporates both natural and man-made materials. Types of garden The major garden types which shall be discussed are: English garden, Mughal garden, Persian garden, Italian garden, French garden, Japanese garden etc. Out of these the Mughal, Persian, Italian and French styles fall in the category of formal gardens, whereas the English and Japanese gardens are classified in the informal style of gardening.

Hedge When shrub is planted on boundary for fencing, it is also called as hedge. In other word shrubs or trees planted at regular intervals to form a continuous screen is called a hedge. It may be ornamental or protective or both. Hedge also become an important feature of formal layout to serve various function as screening of the area out building, tennis court, vegetable garden, hardening of unwanted place etc. All the shrubs cannot be planted for making an ideal hedge due to different nature of growth.

Garden Walls : A garden lover will never like to block the view of his garden by putting a wall along its periphery. A garden as it is enjoyed from inside should also be visible from outside. Low brick or concrete or stone wall of say 60-90 cm height and to put over it some grills. Alternatively walls from 1.8-5.0 m may also be erected depending upon the size of garden. One may grow creepers such as Ficus repens over the wall. Flower Beds: The most essential criterion of a flower beds is display the flowers in the best way possible. It may be born in mind that flowers look best when massed in a bed. The flower beds are of special importance under condition of the plains of India since they can be kept planted throughout the year unlike those in England or other parts of Europe where nothing can be grown in the open between November-March. Annuals and herbaceous, perennial flowers, flowering plants are grown in flower beds to provide massing effect of different colours borders is continuous beds of more length than width containing plant of one kind only.

Annuals Annuals or seassonals are the group of plants which complete their life cycle in one season or in one year. Annuals are commonly known as seasonal as they complete the process of life like germination, growth flowering and seed formation in one season and finally the plant without. Annuals are widely used for garden decoration, cut flower and pot plants. They are frequently grown as bedding plant and in rock garden on the sides of lily pool and in shrubberies.

Annuals Border In this type of border annuals are planted according to their height to beauty of the garden. Annuals border are found two types. Single face border. Double face border. Single face border- In this type dwarf plant is kept on front of beds, medium height annuals are planted in the centre while the taller annuals are planted in the back. Double face border- In this type tall annuals are planted in the center and medium and dwarf annuals are planted in both sides of tall annuals so that full view can be seen from both side.

Trees A trees is a woody perennial plant with clear stem or trunk. Trees trend to be long leaved living up to several 100 year. TREE- logical meaning of each letter T - Temperature and micro-climate moderation. R - Removal of air pollutant. E- Erosion control. E - Energy conservation.

Climbers Climbers are group of plants which have weak stems and ability to climb up the support with the help of modified organs for sunlight and air, twiners differ from climber in the way that they do not posses such modified organs but twine around the support cover it and reach the top. Climber are woody or herbaceous plant which climb up the trees and other tall objects with the help of support of their special modified organ, such as tendrils, root, thorns, rootlets, hooks etc. Tendrils- Bigonia gracilis, Clematis paniculata etc. Thorns- Bougainvillea species, Climbing roses etc. Rootlets- Ficus repens etc. Hooks- Gallium aperine, Rubus australis etc. Climbers and twiners are important group of plants. Climbers and twiners add the beuty, colour or fragrance in the garden and artificial structure like garden wall, topiary, arches, pergola etc. are made with the help of climbers.

Proper handling, packaging, transportation and storage reduce the post harvest losses of fruits and vegetables. For every one percent reduction in loss will save 5 million tons of fruit and vegetable per year. Processing and preservation technology helps to save excess fruit and vegetable during the glut season (off season). The technology has become a necessity to improve the food safety and strengthen nation’s food security. The technology helps to boost export of agricultural commodities in the form of preserved and value added products e.g. mango, pineapple, citrus, grapes, tomatoes, peas, potato and cucumber being processed on a large scale. Principles and Methods of Preservation of Fruits Preservation: Preservation means just protect the foods against the spoilage, but scientifically it may be defined as a science which deals with the process for prevention of decay or spoilage of the food is called preservation. In other words, just controlling the physical, chemical or microbial changes in the foods is called preservation.

Canning: Canning is the process by which sealing of the food product and sterilizing them by heat for long storage is known as canning. History: The term canning was first invented by N. Appert (1804) in France. In honour of the inventor canning is also known as appertization (Appart is known as the father of canning) and Saddington (1807) in England first described the method of canning. Peter Durand (1810) got first british patent on canning of food in tin container and William under wood introduced canning of fruit on a commercial scale in U.S.A. Principle of canning: The main principle of canning is destruction of spoilage organism by means of heat.

Drying- Removal of water from product by influence of non conventional energy source like sun and wind. Dehydration- Process of removal of moisture by the application of artificial heat under controlled condition of temperature, humidity and airflow etc. Advantage of dehydration over sun drying The process of dehydration is much more rapid than sun drying. Dehydration requires less floor area. Dehydration is done under very hygienic condition. Sun drying is not possible in cloudy weather or during rain while dehydration or mechanical drying is not dependent on weather. The colour of dehydrated or mechanically dried fruit and vegetable remain uniform due to uniform drying temperature.

Jam: Jam is a product made by boiling fruit pulp with sufficient sugar to a reasonably thick consistency. Jam is mainly prepared by apple, pear, sapota, apricot, peach, papaya, karonda etc. It can be prepared from one kind of fruits or from two or more kind of fruits. In general jam contains 0.5-0.6% acid and invert sugar should not be more than 40%.

Growth: Growth involve cell division subsequently cell elongation. Increase in volume that is associated with fruit growth largely result of cell division or cell elongation or both. In some fruit such as apple, extension of intercellular space may also contribute the growth. Generally growth by cell division in early stage whereas, cell elongation during later stage. Two distinct type of growth curve are observed when increase in such variable such as fresh weight, volume and dry weight of fruit. Single sigmoid curve Double sigmoid curve In case of single sigmoid growth curve firstly there is rapid increase in size then after decline so there is only one rapid growth is observed e.g. Apple, pear, tomato, cucumber and strawberry. In case of double sigmoid two rapid growth period are separated by an intermediate period that is less growth or no increasing growth curve. Double sigmoid growth curve can be used as two successive sigmoid curve thus there are three clearly define stage of growth.