eChapters

Cucurbits are major crops of countries having a wide variety of vegetables. Cucurbits include bottle gourd, bitter gourd, pumpkins, squashes, ridge gourd, sponge gourd, and cucumbers. Cucurbits are a large, diverse crop group that are susceptible to over 200 diseases (Zitter et al., 1996). A wide range of pathogens affect the productivity of cucurbits. The diseases may be caused by fungi, bacteria, Cucurbits crops are warm-season large group of crops that are cultivated and harvested over different seasons like spring, summer, and winter. These crops as a group are an important part of a diverse and nutritious diet. Melons are eaten as fruits, whereas summer and winter squashes, cucumber, and pumpkin are eaten as vegetables. In addition, cucurbits are used for fiber, utensils, decoration, ceremonial and medicinal purposes.

A wide range of pathogens affect the productivity of cucurbits, which constitute over 200 diseases (Zitter et al., 1996). The diseases may be caused by fungi, bacteria, viruses, or mycoplasma- like organisms. The disease may be soilborne, seedborne (carried by seed), spread by wind, or transmitted by insect vectors. The moisture content of the seed, storage period, prevailing temperature, and degree of invasion influence the development of seedborne fungi (Anjorin and Mohammed 2009). The pathogen may cause seed abortion and rot, necrosis, reduction, or elimination of germination capacity as well as seedling damage at later stages of plant growth, resulting in the develop- ment of the disease as systemic or local infection (Khanzada et al., 2001). The diseases cause heavy loss in terms of yield and quality. The diseases caused by pathogen are controlled by fungicides against fungal diseases, antibiotics for bacterial diseases, or insecticide in case of viruses transmitted by insect vectors. The diseases of cucurbetaceous crops can be managed by adopting different cultural, biological, and chemical methods of disease management. The following management practices are required to be taken into consideration for raising disease-free cucurbitaceous crops:

Introduction

Spine gourd/Teasel gourd (English), (Momordica dioica Roxb.) is popularly known as Kantola or Kakrol in India. It is a perennial, dioecious, cucurbitaceous climbing creeper that belongs to the cucurbitaceae family (Raj et al., 1993). The spine gourd is also called as janglee karela (Harish, 2008). The crop is cultivated for its fruits, which are used as vegetable (Sastri, 1962). Young twigs and leaves of this crop are also used as vegetable (Bandyopadhyay and Mukherjee, 2006). The fruit is rich in ascorbic acid and contain iodine (Rao, 2001). Karnataka and West Bengal are the two main states that cultivate spine gourd commercially. Indira Kankoda I (RMF 37) is a new commercial hybrid variety of spine gourd developed by Indira Gandhi Agricultural University. This hybrid variety is commercially cultivated in the states of Chhattisgarh, Uttar Pradesh, Orissa, Maharashtra and Jharkhand. Spine gourd can also be grown well up to an altitude of 1500 m in Assam and Garo hills of Meghalaya (Ram et al., 2002). This popular vegetable has high demand in market but still remain underutilized and underexploited mainly due to its vegetative mode of propagation and dioecious nature (Bharathi et al., 2010). Adopting improved genotypes and standardized agro- techniques can increased the yield potential of spine gourd (Tiwari and Tigga, 2015).

Introduction

Amaranthus species were grown as the principle grain crop by the Aztecs 5,000 to 7,000 years ago, prior to the disruption ofthe South American civilization by the Spanish Conquistadors. Synonyms such as “mystical grains of the Aztecs,” “super grain of the Aztecs,” and the “golden grain of the Gods” were used to describe the nutritious amaranth grain. Vegetable Amaranthus spp. were and are presently utilized for food from such diverse geographic areas as southwestern United States, China, India, Africa, Nepal, South Pacific Islands, Caribbean, Greece, Italy, and Russia (Stallknecht et. al., 1993). Amaranthus grain is extremely nutritional pseudo-cereal with a higher amount of proteins when compared to true cereals. It is a reasonably well balanced food with functional properties that have been shown to provide medicinal benefits. Amaranth associate underutilized crop and an inexpensive supply of proteins, minerals, vitamin A and C, appears to be a future crop which may substantiate this demand because of its tremendous yield potential and biological process qualities, conjointly recently gained worldwide attention (Topwal, 2019). Amaranth as a unique plant with a long and mysterious history is the obj ect for science and also for business. Its characteristics such as absence of gluten and special composition of oil lead this plant to the position of very important plant for the future. The Advantages of Amaranth for Food Industry: Gluten-free, High-quality protein, Non Food-allergy, Thickening property of amaranth starch. The Advantages of Amaranth oil for Cosmetic Industry: Squalene content has a preserve function for skin and hair against sun and radiation, Available for very sensitive skin, Non- Allergy amaranth oil on skin. Amaranth has a big advantage, because it could be use by two ways-biomass for the bio fuel production and grain for food production (Matusova, 2008). As dyes, the flowers of the ‘Hopi Red Dye’ amaranth were used by the Hopi (a tribe in the western

Onion (Allium cepa) and garlic (Allium sativum) are monocots originating from Asia. These are collectively called as Alliums and formerly classified with the Liliaceae (lilies and relatives). But, now they have been classified in their own family the Alliaceae. The plants ofAlliaceae family are mostly used for seasoning and cooking. Some common crops in the family are bulb onion (Allium cepa), spring or salad onion (A. cepa), bunching onion (A. fistulosum), garlic (A. sativum), leek (A. porrum).

Onions and garlic are prone to several different diseases, especially in wet growing seasons. These often get started on their leaves, and if severe, can reduce bulb growth and yield. Another way onion diseases can cause damage is when they infect bulbs later in the season, which may lead to losses in storage. Some important diseases of onion and garlic are being discussed in this chapter:

Pea (Pisum sativum L.) is considered as the important pulse and popular leguminous vegetable in India. Pea belongs to the genus Pisum, a member of family papilionaceae. Rhizobium bacterium found in root nodules that fixing atmospheric nitrogen and helps in soil fertility. Pea (Pisum sativum L.) originated in the near East and Mediterranean regions. Pea diseases are affect the crop both quantitatively as well as qualitatively. Pea crop diseases caused by the fungal (rust, powdery mildew, downy mildew, aschochyta blight, septoria blight, fusarium root rot, aphanomyces root rot, alternaria blight, wilt, anthracnose, cercospora leaf spot, damping off, seedling rot), bacterial (bacterial blight and brown spot), nematode (root-knot nematode, cyst nematode and lesion nematode) and viral diseases (pea enation mosaic, pea mosaic, pea seed borne mosaic, pea early browning virus, pea streak, pea stunt and cucumber mosaic virus). India is the largest producer, consumer and importer of pulses in the world.

Soyabean (Glycine max L. Merril) belongs to the legume family Fabaceae is one of the world’s most important legume crop and is the second most important cash crop in in India.

Economic Importance

Soyabean contributes to 25% of the global edible oil and about two-thirds of the world’s protein concentrate for livestock feeding (Agarwal, et al., 2013). In many countries such as China, Japan, Korea, Manchuria, Philippines, and Indonesia soyabean is considered to be a source of meat, milk, cheese, bread, and oil and therefore it is called “Cow of the field” or “Gold from soil” (Edwards et al., 2019). Soyabean is a chief source of protein and oil as it contains about 40% protein and 20% oil. Many processed products are made from soyabean such as soy milk, soy flour, soy protein, tofu etc. Due to its amino acids composition, soyabean protein is called a complete protein and is consumed at homes for food purposes. The protein fiber that remains after the oil has been extracted is a good source of animal feed for poultry, pork, cattle, other farm animals and pets. Soyabean is an important foreign exchange earner due to export of soybean defatted oil cake (Agarwal, et al., 2013). Bio diesel is produced from soyabean which is non-toxic, renewable and environmentally friendly and reduces particulate emissions.

Introduction

Cowpea (Vigna unguiculata subsp unguiculata) is widely grown in Africa, Asia and Brazil. The crop is grown on about 7 million ha in warm to hot regions of the world (Rachie, 1985). It acts as a major source of protein (20-30%) for Indian vegetarians. Besides, it contains high carbohydrate. Cowpea is generally rich in lysine and limiting in sulphur amino acids and important for human food and animal feed. The crop is also valuable source of dietary fibre as well as vitamins and minerals including folate, thiamin and riboflavin. Besides this, it can fix about 240 kg ha^-1of atmospheric nitrogen and make available about 6070 kg ha^-1nitrogen for succeeding crops grown in rotation with it (Aikins and Afuakwa, 2008).

The crop is prone to several diseases induced by species of pathogens belonging to various pathogenic groups viz., fungi, bacteria, viruses, nematodes, and parasitic flowering plants, and it constitute one of the most important constraints to the profitable Cowpea production in all agroecological zones. Different diseases like anthracnose, fusarium wilt, bacterial blight, Cowpea mosaic virus (and several other less prominent viruses), cercospora leaf spot, rust and powdery mildew etc are reported to be important disease of the crop. In this chapter detail of these diseases and their integrated management approaches are mentioned.

Introduction

India is the second largest producer of vegetable in the world after China. Every year diseases cause economic losses (8-23%) and also post-harvest losses (20-25 %) in vegetable crops. Bean (Phaseolus vulgaris L.) is a nutritionally important and remunerative crop grown throughout the world and is consumed both as a vegetable, shelled green beans as well as dry beans. It is known commonly known as french bean, common bean, kidney bean, field bean, snapbean, dry bean etc on the basis of its variety and edible purpose. The crop is infected by a number of diseases. Common bacterial blight, Anthracnose, White mold, Bean Common Mosaic, Bean yellow mosaic, Web Blight, Halo blight, Dry root rot and wilt, Bean Rust are some of the major diseases.

Bacterial Blight of Bean

Three types of bacterial blight are found to occur in beans viz. Common bacterial blight or Bacterial blight, Halo blight and Bacterial brown spot. These three diseases affect leaves, pods, stems and seeds in similar manner such that it is usually impossible to distinguish the diseases from one another based on the visual symptoms. While common blight is usually more prevalent in warmer weather, the other two occur more in cool weather.

Introduction

Colocasia esculenta (L.) Schott, also known as taro, belongs to the family Arecaceae. Taro is believed to have originated in Southern or South-East Asia, and to have been dispersed to Oceania through the Island of New Guinea to many centuries ago but cultivated in Asia for more than 10,000 years. Taro is considered as an important vegetable grown throughout India. Taro is herbaceous perennial plants with a large corm on or just below the ground surface and can be grown in the ground or in large containers. They can be grown in almost any temperate zone as long as the summer is warm.

Taro root contains very significant amount of dietary fibre and carbohydrates, as well as high levels of vitamin A, C, E, B6 and folate, as well as magnesium, iron, zinc, phosphorus, potassium, manganese and copper. Thogh negligible, the plant is also known to provide some protein in our diet. As Taro is a great source of fibre and other nutrients, it offers a variety of potential health benefits, including improved blood sugar management, gut and heart health.

Globally, taro is grown in an area of 1.6 m ha producing 11.66 mt with an average productivity of 7.25 t ha^-1 (FAO, 2009). The plant can be grown in wide range of climatic condition but during growth period taro is prone to attack by at least twenty- three (23) pathogens, of which, only a few causes serious reduction in the potential yield of the crop. Some of the mentionable diseases that commonly occurs and causes yield loss of the plants are as follows:

Introduction

Elephant foot yam (Amorphophallus paeoniifolius (Dennst.) Nicolson) is an important edible tropical tuber crop since time immemorial in the tropics and sub-tropics (Behera et al., 2009) and regarded as “King of tuber crops” due to its higher biological efficiency as a food producer ). It belongs to the family Araceae. Tender stem and leaves of this tuber crop are used for vegetable purpose. The corms are rich in nutrition and contain 18.0% starch, 1-5% protein and up to 2% fat. Leaves contain 2-3% protein, 3% carbohydrates and 4-7 % crude fibre. It has great scope for commercial exploitation as a medicinal crop in pharmacological industry and widely recommended as a remedy in all three of the major Indian medicinal systems: Ayurveda, Siddha and Unani. The corm is prescribed for bronchitis, asthma, abdominal pain, emesis, dysentery, enlargement of spleen, piles, elephantiasis, diseases due to vitiated blood, and rheumatic swellings. Pharmacological studies have shown a variety of effects, specifically antiprotease activity, analgesic activity, and cytotoxic activity. It has also been found to be a potential inhibitor of bacteria activity when used with antibiotics. In addition, Amorphophallus corm is a good sources of phyto- aestrogens and are effective alternate or complementary to conventional hormone replacement therapy for symptoms associated with menopause and chronic degenerative diseases in women. It is a crop of South-east Asian origin, and grown widely in Philippines, Malaysia, Indonesia and South eastern Asian countries. In India, the crop is popular in the state of West Bengal, Andhra Pradesh, Kerala, Uttar Pradesh, Bihar, Madhya Pradesh, Maharashtra, Orissa, Tamil Nadu and Karnataka. West Bengal is the highest producer of elephant foot yam (293.84 thousand MT in the year 2015-16) followed by Andhra Pradesh (207.52 thousand MT) and Kerala (110.37 thousand MT) (Source: National Horticultural Board). However, the crop is gaining popularity dueto its shade tolerance, easiness in cultivation, high productivity, less incidence of pests and diseases, steady demand and reasonably good price.

Radish (Raphanus sativus) is a cool weather crop and its origin is in Mediterranean, rapid growing annual or biennial plant belongs to family Brassicaceae, grown for its edible taproot. Its edible roots are having different color from as white to red. Radish is generally grown as an annual plant, surviving only one growing season. It is crop of tropical and temperate region. It is growing as herb in West Bengal, Bihar, Uttar Pradesh, Karnataka, Punjab and Assam areas are major radish growing states. Radish is good source of vitamin B6, Calcium, copper, magnesium and riboflavin. Also it is rich in ascorbic acid, folic acid and potassium.

Alternaria Blight

Economic Importance

Alternaria leaf spot diseases occur in every part of the world, in both vegetable crops and seed crops and most important disease of Brassica species, often results in severe yield losses. It is considered as a number one disease of radish affecting both fresh vegetable and seed production. The disease is more severe when the plants are left for seed production in the field and causes significant reduction in seed yield. Alternaria black spot of radish; black pod blotch of radish. A. japonica is a seed-borne pathogen of plants in the Brassicaceae. A. japonica is known to affect most parts of infected plants depending upon growth stage. There are reports of it on the hypocotyls and cotyledons of seedlings and on the leaves, petioles, stem, inflorescence, fruits (siliquae) and seeds of adult plants. A. japonica occurs in all parts of radish (Raphanus sativus) seed. Its presence in the embryo can result in seed death, but in milder infections it will affect seedlings after germination, causing seedling blight both before and after emergence.

Introduction

Broccoli (Brassica oleracea L) belonging to family Brassicaceae, is an herbaceous annual or biennial plant which is cultivated for its edible flower heads being are used as vegetable or salads. The broccoli plant has a broad green stalk, or stem, that give produces thick, leathery, oblong gray-blue to green in color leaves. The plant produces large branching green flower heads covered with numerous white or yellow flowers. Broccoli can be annual or biennial depending on the variety. Broccoli is a rich source of vitamins, minerals and antioxidants and has a reputation as super foods (Hatanaka and Ware, 2020).

It is admitted that they are susceptible to a numerous of serious diseases that leads to reduction in yield. Thus, it is the utmost requirement to control such biotic stressors in order to obtain desired quality and decent yields. The most important diseases and its control measures are being portrayed in this chapter for both home gardener and the commercial producers for cruciferous vegetables particularly broccoli (Mani et al., 2020).

Cruciferous vegetables are important Kharif vegetable crops, which are grown both for table and seed purposes. This vegetable group constitutes crops like cauliflower, cabbage, radish, turnip and knol-khol. These crops are grown throughout the country and are attacked by number of diseases which not only reduce the quantity but also quality of the produce. Important diseases of Knol Khol are described below:

Major Fungal Diseases of Knol-Khol

Alternaria leaf spot

Economic Importance

It is of concern in north and central India where appreciable seed losses in terms of size, colour and germinability are reported

Blackrot of Cabbage

Economic Importance

Blackrot is an important bacterial disease of cabbage and other crucifer crops worldwide. The disease was first described in New York on turnips in 1893, and has been a common problem for growers for over 100 years (Smart and Lang, 2013). Blackrot has been given many names such as bacterial blight,black stem, black vein, stem rot or stump rot (Pfeufer and Davis, 2019). These pathogen is particularly damaging to cabbage and cauliflower, but turnip, rutabaga, collard, kohlrabi and Chinese cabbage are also susceptible. Broccoli and radish aregenerally resistant to Blackrot (Flynn,1999).

Introduction

Okra (Abelmoschus esculentus L., Family: Malvaceae) also known as lady’s finger has been originated in Africa and introduced to India during early 20^th century. As an economical vegetable crop, it can be grown in tropical as well as sub-tropical parts of the world. During 2018-19, the total area under cultivation of okra was 511 thousand ha while the production stood at 6219 thousand MT in India (Horticulture Statistics Division, 2018). Okra can be grown on wide range of soils, but higher yield can be obtained in well-drained fertile soils with adequate organic matter. It is utilized for various purposes in terms of fresh leaves, buds, flowers, pods and stems providing a rich source of protein, carbohydrates, vitamins, calcium, potassium, enzymes, and total minerals in human diet. The mucilage has medicinal applications when used as a plasma replacement (Nilesh, et al., 2012), and the seeds contain 20 to 40% oil content (Sorapong, 2012).

Okra pods (per 100 g edible portion) are composed of water (88.6 g), energy (36 kcal), protein (2.10 g), carbohydrate (8.20 g), fat (0.20 g), fibre (1.70 g), Ca (84.00 mg), P (90.00 mg), Fe (1.20 mg), p-carotene (185.00 μg), riboflavin (0.08 mg), thiamine (0.04 mg), niacin (0.60 mg) and ascorbic acid (47.00 mg) ((Priya, et al., 2014).). Therefore, okra has been called as “a perfect villager’s vegetable” due to its robust nature, high dietary fibre as well as distinct seed protein with a balance of both lysine and tryptophan amino acids. Okra production is subjected to various diseases caused by fungi, virus and nematodes as a major biotic constraint. The mandates of integrated disease management of okra are to impart knowledge about symptoms, causal organism, disease cycle and epidemiology of major diseases. The present review will give a brief highlight about major diseases of okra viz. yellow vein mosaic, wilt, powdery mildew, cercospora leaf spot, damping off, collar rot and root knot nematode.

Chilli is reported to be an inhabitant of South America and widely scattered in all tropical and sub-tropical countries including India. Amongst all the important consumed crops, chilli occupies a dominant position and its economic losses worldwide due to few serious diseases like chilli anthracnose, Phytophthora leaf blight and fruit rot, bacterial leaf spot, bacterial wilt, Cercospora leaf spot, chilli leaf curl virus and so on. Capsicum annuum L., C. frutescens L. are the biological names of chilli. Bird’s eye chilli is grown in Mizoram and some areas of Manipur and Assam. Chilli has got its own regional names. In Hindi, it is popularly known as Lal Mirch, in Gujrat as March, in Marathi as Mirchi and so on. Kanthari White is grown in Kerala and some parts of Tamil Nadu. Kashmir chilli is grown in temperate region such as Himachal Pradesh, Jammu and Kashmir and also in sub-tropical regions of North India. Red chilli held high amount of vitamin C and provitamin A, whereas green chilli too contain a considerable amount of both substances. In addition, peppers are a good quality source of most B vitamins, vitamin B6 in particular. They are very high in Potassium, Magnesium and Iron supplement.

Introduction

Brinjal, Solanum melongena L. a solanaceous and the native vegetable of India is very favourite among the Indians. It is an economically important vegetable among the small scale farmers and low income consumers of India. It ensures some assured source of income to the resource poor farmers throughout the year due to long fruiting and harvesting period. Brinjal fruits are of a low calorie value and have a mineral composition that is beneficial for human health; these fruits are rich source of minerals (potassium, calcium, phosphorus, sodium, chlorine, iron etc.) and vitamins and have some medicinal importance (Choudhary, 1967). In India, brinjal is grown on the wide range of soils and other variable environmental conditions. In production and productivity, India stands second in the world after China which is mainly grown in the states like West Bengal, Orissa, Bihar, Gujarat, Maharashtra, Karnataka, Uttar Pradesh and Andhra Pradesh. The world production of brinj al in the year 2016 was estimated to be 51.29 million MT in an area of 1.79 million hectare with productivity of 28.59 MT per ha China, the world leader of brinjal production produced 32.03 million tones of brinjal with a productivity of40.96 Mt per ha in an area of 0.78 million ha. The productivity of brinjal as compared to China is very less (18.90 MT/ha) in India although we are the second largest producer ofthis popular vegetable (FAOSTAT Website (http://faostat3.fao.org/home/E).

Tomato (Lycopersicon esculentum Mill.) is one of the most important vegetable crop and is known as protective food due to its wide spread production and special nutritive value. Tomato is referred to be native of tropical America. In the 16^th century, it got spread from America to other parts of the world and became popular in India within the last six decades. It is known as world’s largest vegetable crop after potato and sweet potato. The overall world production of tomato is 1,180,000 tons with a productivity of 65 t/ha. Contribution of USA in tomato production is 13.2 million metric tons to the total world production (FAOSTAT). USA ranks third in position in the total world production of tomato after China and India (FAOSTAT). India produces 22,337MT of tomato from 801ha area.

Fungal Diseases

Fusarium Wilt

Economic Importance

Fusarium wilt caused by Fusarium oxysporum being so widespread, turns out to be a significant problem in many crops. It is one of the most widespread and damaging diseases of tomato wherever tomatoes are grown intensively. The pathogen also causes damage to many other crops likepotato, and pepper of the family Solanaceae. Yield losses of effected crops can goup to 45% in tomato in India.

Introduction

Potato is mostly considered as a vegetable crop in India, whereas it is a staple food crop in Europe, Canada, Australia, U.S.A, South America, Russia, Asia and other countries. In India, it is cultivated extensively in the hilly tracts during December-March or March-June and in the plains during September-January, as it requires cool and moist climate condition. As per FAOSTAT (2015), the potato production in India during 2013 was 45.34 mt from 1.99 mha area with a productivity of 22.76 t/ha. There are several varieties of potato grown in India and many diseases, some of which cause considerable damage to the crop. Potato crop can be affected by diseases caused by fungi, bacteria, virus, viroids and others by non-parasitic.

Late Blight

Economic Importance: Late blight is one of the most devastating diseases of potato throughout the world. It is recorded in area with frequent cool and moist weather. The disease is believed to have been introduced into Europe from South and Central America and spread to other countries which include the East Coast of Canada, Western Europe, Central and Southern China, South Eastern Brazil and the tropical highland. It created history by causing a famine in Ireland known as Irish Famine during 1845-46 resulting in death of many people due to starvation, dysentery and typhus spread among the farmers and subsequent migration of people from Europe especially from Ireland. Late blight has the tremendous potential to cause upto 70% reduction in the yield in a susceptible cultivar. Region wise economic importance of late blight shows that the disease takes highest toll of potato in Sub-Saharan Africa (44% crop losses) followed by Latin America (36%), Caribbean (36%), South-East Asia (35%), South-West Asia (19%)

India is bestowed with varied climatic conditions and a variety of horticultural crops are produced. It is estimated that 20-30% of the produce is lost before consumption because of various reasons including improper storage and this is where the need of processing for preservation arises. There are various ways of preserving the produce and various ways to process it.

Preservation is defined as methods of extending the shelf life of the produce in its original form or in a different usable form. The basic principle of preservation involves strategies which aim at reducing the spoilage. The horticulture produce is spoiled by microbial infection or infestation. Prevention of microbial damage can be achieved by keeping the produce away from microbes, by removing the microbes, obstructing the proliferation and by killing the microbes. Infestation in the harvested fruits may lead to other microbial infection and spoilage due to rotting.

Horticultural crops are highly perishable and the post-harvest loss is estimated to be 20-30% every year. There are various factors associated with post-harvest losses. It includes pre-harvest cultural operations, maturity index at which the produce is harvested, methods of harvest, pre and post-harvest treatments, packing materials and storage methods. Postharvest technology can be defined as the techniques which help to reduce the post-harvest losses.

Assessment of harvesting stage

Climate may be related to periodical events in plants life. The science dealing with this relationship is termed as phenology. The phenological data for horticultural crops include dates of planting, germination, flowering, fruit set, ripening and harvest. These dates are determined by the climatic factors prior to as well at the time of harvest. A useful phonological concept for the prediction of the harvest time is based on degree days. A “ Degree day” can be defined as a day when mean daily temperature is one degree above the minimum temperature for the growth of the plant. The minimum temperature for the growth of a particular plant is termed as “zero temperature”. Zero temperature vary according to crop. E.g. if zero temperature of a particular crop is 50°F, then a day with mean temperature of 68°F would provide 18° days. The degree days are also called as “heat units”. It can be determined by how many degree days are needed for the horticultural crop to reach harvesting stage.

Plants grow in the open in nature, hence are subjected to biotic and abiotic stress.

Biotic stress is due to living components such as:

Insects and pests

Nematodes, mites, snails, slugs etc.

Vertebrates like rats, birds, jackal, bats etc.

The plant experiences biotic stress when root, stem, bark, shoots, leaves, buds, flowers and fruits are damaged by the influence and activity of biotic factors.

Biotic factors Diseases

Like the pests, diseases also cause stress to plants. Diseases are caused by fungus, bacteria and virus. Sometimes the exposed part of insect eaten plant part becomes the entry pathway for fungus, bacteria and virus.

Horticulture is an art and science of growing plants. It is the practice of engaging ailing people in various horticultural activities such as gardening and flower arrangements in order to improve their physical, mental and spiritual health. Research confirms that health benefits escalate manifold when people connect with nature and plants by viewing and/or interacting with them. Major benefits of horticultural therapy includes sensory simulation and mood enhancement, mental relaxation, improvement of memory and concentration and an overall feeling of wellness. Horticulture therapy also helps in cultivating positive emotions and provides a meditative mood. It eases both physical and emotional pains and also improves social skills. It is proven that a simple viewing of a garden benefits a person both physically and mentally.

This practice has been used as therapy for centuries. In 1798, Dr. Benjamin Rush, considered as the “Father of American Psychiatry” documented that gardening has positive effects on mentally ill patients. Following World War, II gardening was used as a form of occupational therapy for war veterans. The concept of using nature to improve human health began to gain credibility in 1970’s. Rachel and Stephen Kaplan (1989) found that natural environments had relaxing and restoration benefits for people. The Journal of Therapeutic Horticulture, a peer-reviewed publication of the American Horticultural Therapy Association, has published authentic research papers since 1986. The American Horticultural Therapy Association (AHTA) serves to promote and advance horticultural therapy as a therapeutic intervention and rehabilitative approach. Degrees and certificate programs in horticultural therapy are offered at several colleges and universities and information is available on AHTA website.

Horticultural therapy is a worldwide practice and recognized as an effective treatment for clients of all ages and abilities. It is being used in several diverse settings including hospitals, rehabilitation centres, youth outreach and recovery programs, nursing homes, senior care facilities, prisons, mental health facilities, schools, botanical gardens etc. The client is engaged in horticultural activities facilitated by some trained therapists to achieve specific and documented goals. AHTA believes that horticultural therapy is an active process that occurs in the context of an established treatment plan where the process itself is considered as the therapeutic activity rather than the end product.

Horticulture therapy is a growing profession in rehabilitation and addiction centers, vocational centers, youth mental health programs, hospitals and nursing homes, and old age homes or senior citizen centers, mental health centers, schools and colleges.

Flowers of the garden are brought indoors to enjoy the beauty. Fresh flowers are arranged in various styles according to one’s choice. There are two major and distinct styles of arranging fresh flowers, namely the European and the Japanese. Both the styles are greatly influenced by the place where they have been originated. Flowers are also dried and used for different arrangements. Fresh flowers are used as ornaments and also for making floral patterns on the floor called Rangoli.

A garden has a number of elements which give shape to its breath-taking view. Both animate and inanimate elements are included to achieve a beautiful garden The living elements are lawns, rock garden, water garden, sunken garden, hedges, edges, shrubs, topiary, flower bed, specimen plants, pergola and arches, while the inanimate elements, also called as adornments, are stones, road, footpaths, seats, lamps, lanterns, steps, bridges, huts, swings, fountain, cascade, bird bath, clock tower, umbrellas, sculptures etc.

Micro propagation in also called as in vitro propagation. In vitro is a Latin word, meaning ‘in glass’. It refers to procedures done in controlled artificial environment, outside a living organism. These procedures naturally occur in the living system. Opposite to in vitro is in vivo which is also a Latin word, meaning ‘in living’. Biological processes that occur within the living system.

Micro propagation refers to the multiplication of plants, in aseptic conditions in containers under controlled nutritional and environmental condition. Micropropagation is done in artificial growth medium from various plant parts like meristem tip, embryos, anthers, axillary buds, leaf section, shootlips etc. It is a method by which a true to type and disease free plant can be regenerated from a miniature piece of plant throughout the year. Some popularly grown crops from tissue culture are as follows

Ornamental plants - orchids, lilium, gerbera, cordyline, begonia, ficus, etc.

A kitchen garden/ nutrition garden is a vegetable garden where the vegetable crops are grown in the backyard of a house or any available space in compound or rooftop of the house, to meet the daily requirement of the family. All the members of the family are collectively involved in a kitchen garden.

For a balanced diet, 300 g of vegetables are to be included in our daily food. But on an average, Indians take only 160 g per day. Hence to fill up the gap, vegetable cultivation not only in farmers’ holdings but also in the home gardens is encouraged.

Organic cultivation is a deep rooted cultivation tradition, which had been practiced in many parts of the world, before the advent of the practice of use of chemicals.

After the green revolution there has been exponential usage of chemicals in agriculture, right from planting to harvesting. Chemicals are used in the form of nutrient inputs or for plant protection against pests, diseases, weeds and keeping deficiencies at bay. Nevertheless, after the awareness regarding the detrimental effect of chemicals on soil, climate and human health, there has been a lot of contemplation on substituting the chemicals with the organic alternatives. Growing crops using organic inputs is known as ‘organic cultivation’. Organic cultivation is a sustainable form of cultivation where a proper balance is maintained and management of plant nutrition, pests, weeds and diseases is done in a sustainable manner, keeping the soil microflora intact and active. It does not release any chemical gases in the atmosphere, does not make the soil acidic and the soil does not lose its structure and texture. Contrary to chemical farming, where over a time period, the soil quality, texture and structure is lost, in organic practices, the soil texture, quality and structure improves over time, the plants become strong and the quality of the produce is improved. Other than organic inputs, organic farming relies on some sustainable practices like using native germplasm, crop rotations with legumes, green manuring, mulching, inter cropping, mixed cropping, incorporation of farm and animal waste compost. These simple age old practices build to organic content in the soil and elevate the soil’s efficiency to make nutrients and water to the plants. The soil microflora and earthworms become biologically active, efficient and exponentially proliferate. The goal of organic cultivation is to get maximum produce from the soil in such a manner that the soil, air and water are clean and protected.

GAP stands for “Good Agricultural Practices” which are used for production of safe agricultural produce which has zero microbial load on it and inside it. It is important for the producer to be acquainted with GAP.

Good Agricultural Practice of horticultural crops are intended to apply to the growing and processing of all produce as traded and used in the European Union. Hence, they apply to the production of all plant materials used in the food, feed and medicinal industries. They also apply to all methods of production including organic production in accordance with the European Union regulations.

The farmers involved in the cultivation of horticultural produce should ensure that the there is no damage to the existing wild life and the biodiversity in the farms which are maintained. It is advisable to regulate wild gathering by a specific guideline.

The main aim of GAP guidelines is to ensure that the produce meets the demand of the consumer and is of high quality standard.

It is therefore, important that they are produced hygienically, in order to reduce microbiological load to a minimum. They are produced with care, so that negative effect on plants in the course of cultivation, processing and storage is limited.

All participants in the production process are required to comply with these guidelines voluntarily and to develop practical measures to achieve it.

Greenhouses are frames or inflated structures covered with a transparent or translucent material in which crops can be grown under partially controlled or totally controlled conditions of atleast. It is large enough to permit persons to work within, to carry out cultural operations. Greenhouse cultivation as well as other modes of controlled environment cultivation has been evolved to create favourable microclimate, for the crop production all through the year or during off season, when the produce is highly priced and remunerative. Green house is a broader term of protected structures which includes different types of structures according to the need. Green houses vary in size and complexity from small home or hobby structures to large commercial units, from solar green house to sophisticated environment controlled ones.

Plant growth regulators are defined as chemicals other than nutrients and vitamins which regulate (or) modify the physiological process ofthe plant. A plant hormones or phytohormones are chemical substances which are naturally produced by plant in specific organs and are translocated from site of synthesis to the site of action. They bring about specific physiological response, even in very low concentration. The quantity of synthesis of these hormones differ from plant to plant, plant internal and external factors. They are readily absorbed and these chemicals move rapidly through the tissues when applied to different parts of the plant. A plant growth hormone may be termed as a plant growth regulator, but not vice - versa, since other than natural plant hormones, plant growth regulators are synthetically manufactured chemicals.

Plant growth regulators have a diverse chemical composition. Based on the general response the chemical mediates in the plant system, they are classified as growthpromoters and growth inhibitors/retardants. However, a particular growth regulator may be growth promoter at a lower concentration and growth inhibitor at higher concentration.

The term growth refers to an irreversible increase in size and weight of the plant. It normally reflects an increase in protoplasm, which may occur through increase in size of the cell and number of cells. Hence, the process of cell elongation and cell division provides the basis for growth. Cell division and enlargement are complicated processes involving synthesis of many organic compounds such as protein, cellulose and nucleic acid, besides the physical force required, which results in cell enlargement. The growth of the whole plant is compartmentalized into areas called ‘meristem’ where cell division and cell elongation are localized. The meristem cells such as shoot apex, root apex, cambium and the intercalary zones undergo repeated mitosis resulting in replication of DNA and nuclear material and finally the cell mass increases. Adjacent to this area of meristematic activity is the region of cell elongation, which phases in to the region of differentiation and maturation.

The increase in protoplasm (occurring in cell division and elongation) is brought about through a series of events in which water, carbon - di-oxide and inorganic salts are transformed into living materials. These events include (a) photosynthesis (production of carbohydrates) (b) nutrient absorption and translocation (uptake of water, nitrogen and other mineral elements) and (3) anabolism (synthesis of various materials produced in plant from the carbon fragments produced by photosynthesis and from the inorganic nutrients and water absorbed from the soil). The energy required for all these processes is provided by a catabolic process viz., respiration (degradation of sugars and fats to release energy). The net balance of anabolism and catabolism results in growth of the plant.

The types of crops and the practices used to grow them and the sequence in which they are grown altogether refers to cropping system. It comprises of all components required for the crop production and their relationships with the environment. Traditionally the cropping systems aim at maximizing the per unit area productivity, which can be done by growing improved high yielding varieties, by adequate and scientific crop management practices and by increasing cropping intensities with the help of different cropping patterns.

In today’s world cropping system should produce more, at the same time the practices should be ecologically and environmentally sustainable. There should be efficient utilization of land and water. It should be designed to conserve soil, soil moisture and improve soil resilience.

Training and pruning of horticultural crops is very important practice to obtain a strong frame work of tree and sustained productivity. It is necessary to understand the various terms used to make the subject more comprehendible.

Crotch: It is the angle made by the scaffold limb to the trunk or the secondary branch to the scaffold limb.

Head: The point on the trunk from which first branch arises.

Leader: It is the main stem growing from ground level up to the tip dominating all other branches.

Low head trees: Trees in which scaffold branches arise within 60-70 cm height from the ground level.

High head trees: Trees in which the scaffold branch arise 120 cm above the trunk.

Scaffold branches: The main branches arising from the head are known as scaffold branches.

An orchard is the place where different kinds of fruit crops are grown in large scale. An orchard is a long-term investment and needs lot of planning and expertise. The orchard crops are generally trees, which ultimately have a large spread, so when they are planted, the distance between plants and rows is kept keeping in mind the final spread of the tree. So, before the trees attain their full growth, some suitable crops which are of short duration, like vegetables, flowers, spices and herbs are grown as intercrops.

Fruit trees are perennial, may be tropical, sub tropical and temperate types and thus require proper environmental conditions and suitable management practices for their successful growth.

Pot mixture is the media, used in the pots for propagation of nursery plants. It is the combination of different materials in a particular proportion to create better environment for rooting, growth and development of plants.

The most commonly used ingredients to make potting mixture areas follows

Plant propagation techniques refer to the methods by which the plants are multiplied and increased in number.

Methods of Propagation

i) Sexual Method of Propagation - Seeds are used as propagating material.

ii) Asexual Methods of Propagation - Plant parts, other than seeds are used for plant propagation.

Different crops are grown in a field. Any plant growing in a place where it is not desired competing with the main crops, has to be weeded out and such plants are called ‘weed’.

Effect of weed menace The weeds

Reduce crop yield and production efficiency. It competes with the main economical crop for space, water and nutrients.

Reduce crop quality.

Hamper intercultural operations.

Reduce crop quality.

Obstruct the flow of water in the irrigation channels.

Exert allelopathic effect on crops.

Harbour insect and pests, which affect the main crop of interest.

Increase the cost of production.

Water is an extremely essential component in plant growth and development. It is of utmost importance for photosynthesis, cell division, cell growth / elongation, respiration, nutrient uptake, mineral utilization and much other metabolic process, which directly affect the quantity and quality of the produce. Hence quantity and quality of water play a vital role in performance of a crop. A well distributed water supply, throughout the growth of plant is essential. Rainfall is the major source of water for the crops. Rainfall recharges the surface water resources such as rivers, streams and ponds and also the ground water resources like wells.

Nutrient management is one of the key aspects that ensure good quality produce in optimum quantity. Nutrient availability influences growth and productivity of crops. Sixteen elements are recognized as essential nutrients for growth and development of plants. These essential elements are carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, iron, zinc, manganese, copper, boron, molybdenum and chlorine. While carbon, hydrogen and oxygen are derived from air, soil and water, other elements are taken by the plant roots from the soil, according to the requirement of the plant. The soil contains these elements in varying quantities depending on the origin of the soil. According to the quantity of requirement of these elements by plants for its various growth processes,the elements are classified into different categories.

Major nutrients or primary nutrients - These are required by plants in large quantities because they are involved in all the processes of plant growth and development. Major nutrients are nitrogen, phosphorus and potassium.

Secondary nutrients - These are required by plants in relatively smaller quantities for growth and development. Secondary nutrients are magnesium and sulphur.

Micro nutrients - As the name suggests, these are required by plants in minor quantities for their physiological processes. These elements are iron, zinc, manganese, copper, boron, molybdenum and chlorine.

Each of the plant nutrients has a definite quantitive role and specific function in the physiological processes of plants. If any of the essential element is deficient or absent in the soil sysem, the plant growth is affected negatively and this is reflected as inferior quality produce. On the contrary, if a nutrient is excess in the soil system, it hinders in absorption of other nutrients and also may itself be toxic. Hence to get the required growth, quality and quantity of the produce, optimum availability of all the nutrients should be ensured.

The performance of plants is affected by the soil in which it grows and climate and micro climate of its surroundings.

Impact of soil

The soil provides anchorage, nutrients and water for plant growth. Soil fertility status, structure and texture influence the plant growth and productivity.

Classification of soil

On the basis of the organic and inorganic contents and particle size and texture, the soils have been classified. The inorganic matter in the soil constitutes of varying amount of sand, silt and clay, on the basis of which the soils are classified as follows.

Sandy soil

These soils have coarse textured and large pore spaces, have poor water holding capacity. Retention of nutrients in this soil is very poor. This type of soil is suitable for precocious crops. Sandy soils initiate rapid root growth, hence good as propagating medium. Since sandy soils has low in nutrient content, supplementation of adequate nutrition is imperative to achieve good plant growth.

A number of tools, implements and machineries are used in cultivation of horticultural crops to make every operation easy and efficient. There are a number of operations involved in cultivation of horticultural crops, like making of nursery, propagation of plant material, field ploughing, breaking of clods, levelling, making bunds, sowing and planting, plant protection, training, pruning, harvesting, lawn mowing etc. All these operations are physically taxing and cannot be carried out efficiently without proper tools, implements and machineries. Following are some important tools -

1. Bill hook: To cut and remove big sized unwanted branches of trees.

2. Buckets and plastic pots: used in the orchard for spraying, transport water, carry harvested produce etc.

3. Budding and grafting knife: The budding and grafting operations in propagation of many horticultural plants are carried out using budding and grafting knife.

4. Country plough: Used in field preparation for ploughing the soil, incorporation of organic manures into the soil at the time of last ploughing, summer ploughing in conserving of soil moisture.

5. Crow bar: Used to loosen the soil, digging and deepening the pits and channels.

6. Dibbler: Used to make holes and sow the seeds in the nursery as well as in the main field.

7. Digging fork: It is of a great use in harvesting the tuber crops without damaging the produce.

The Government of India has established boards for important crops. The boards are statutory bodies which help in guiding the production and export. The main objectives for setting up the boards are -

To monitor and promote the export of primary items.

To empower the producers by providing trainings and close guidance.

To conduct research to improve the commodity, e.g. Central Coffee Research Institute, Coir Research Institute etc.

To advise the government on policy matters such as price fixing, fixing quota for export and signing trade agreements.

To promote the commodity by opening offices and outlets in India and abroad.

To showcase the commodity by participating in trade fairs and exhibitions.

The Horticultural crops show wider adaptation and therefore exact delineation of the agro-climatic areas specific to each crops is not possible, except for the typical temperate and tropical species. However, our country can be broadly divided into seven zones for horticultural crops as indicated below:

1. Temperate Northern Region

Comprising of states of Jammu & Kashmir, Himachal Pradesh, Hilly areas of Uttar Pradesh and West Bengal. Temperate fruits, cool season vegetables are the important horticultural crops in the zone.

2. North Western Arid Region

Comprising ofthe entire Rajasthan state, Gujarat and parts ofPunjab & Haryana. Arid fruit crops like ber, pomegranate, amla, date palm, wood apple and seed spices like coriander, cumin, fennel occupy major area in this zone.

3. North Eastern Sub-tropical Humid Region

Comprising of states and union territories like Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland and Tripura. Fruit crops like banana, pineapple, citrus, jack besides plantation crops like tea and large cardamom are also grown here.

Horticulture is a wide field and includes a great variety and diversity of crops. In general, these crops are classified as follows:

1. Crops grown for the food and/or vitamin and mineral content, for e.g., apple and sweet potato.

2. Crops grown for their beverage properties, for e.g., tea and coffee.

3. Crops grown to beautify the environment, for e.g., the grasses of the well planned lawn.

4. Crops grown to express sentiments, for e.g., cut roses, jasmine.

5. Crops grown for perfume for e.g., rose, jasmine.

6. Crops grown for spices for e.g., pepper, nutmeg.

Horticulture deals with the art, science, business and technology of cultivation and management of horticultural plants. The word Horticulture is derived from two Latin words viz. ‘Hortus’ (means garden) and ‘Culture’ (means growing). Horticulture is an aesthetic science that deals with cultivation of fruit, vegetable, spice, plantation, medicinal, aromatic and flower crops. There is a vast therapeutic use of horticulture wherein gardening and aroma therapy are used to deal with new age maladies like depression and various addictions.

In ancient times, huge gardening spaces to grow large number of fruits, vegetables and flowers were available and these areas were demarcated with the help of high walls. This enclosed area was referred to as garden. This led to the term garden culture. The land area is decreasing due to industrialization and population growth, at the same time, there is a drastic increase in demand for horticultural produce. To meet the increased demand for horticultural produce and to cope up with the space constraints, multitier cropping systems, vertical gardening and other intensive cultivation practices are being resorted to. Hence, horticulture may also be described as the “Practice of growing and manipulating plants in a relatively intensive manner”.

Presently, fruits, vegetables, flowers and ornamentals are grown not only within the home premises, but also in large quantities on a commercial scale. In other words, many horticultural crops throughout the world are grown primarily as business enterprises. Thus, horticulture has two aspects in general i.e., the amateur and the professional. In addition, with the establishment of horticultural experiment stations as an integral part of colleges and universities, comparatively a large amount of scientific information on the behaviour and cultivation of horticultural plants and products is freely available. This information or literature, constitutes the science of horticulture, and the application of this scientific information constitutes the “Technology of Horticulture.” Thus, present day horticulture may be defined as the science and technology of production, processing and merchandising of fruits, vegetables, flowers and ornamentals where each crop has its own science and technology. Consequently, horticulture may appear differently to different people. To a teacher, professor, research scientist, extension official and landscape architect, it is an applied science and a profession, while to a commercial producer, wholesaler, a retailer of horticultural products, or to the manufacturers or seller of horticultural products, it is a business. It is also a fascinating hobby for connoisscur.