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India is a major exporter of vegetables with 10th position in the world. In the past, the Dexport of Indian vegetables was restricted to potatoes and fresh onions, however, now, the Government of India finds great opportunities for expanding exports of several vegetables including lettuce, fresh peppers, tomatoes, squashes, gherkins, etc. Under World Trade Organization (WTO) regime, the development of stronger seed industry and improved production technology will give India a competitive edge in global market. New opportunities and challenges are emerging every day in the dynamic and global vegetable-based industries. However, such opportunities can be harnessed only if assured quality, in terms of organic farming and reduced pesticide residues, is maintained (Shanmugasundaram, 2004).

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.

Water

• Water constitutes about 35–95% of the different portion of the plants. The leaves of the plant contain 35–95% water, Roots 60–90% and Fleshy fruit contain 70–90% 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.
• Soil needs the application of water to:
• Remove stress condition.
• Release nutrients in the soil solution for absorption by plants.
• 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.

12.1 INTRODUCTION

Water is a factor of prime importance in agriculture industry. Water management is one of the largest and most important inputs into an orchard. An efficient water management refers to artificial application of water, i.e., irrigation in crop root zones in case of soil moisture deficit and removal of water, i.e., drainage from the root zone in case of excess so as to provide the crops a most optimum soil moisture regime for best production. It means how best we are in irrigating and dewatering our fields so that plants are protected from stress as well as water logging (Goswami, 2015). Water resources are continuously overburdened with excessive drafts and water sources are shrinking at faster rate. Groundwater levels are falling at the rates faster than ever. Under this type of circumstances, judicious use of water should be given due attention for water conservation and also in increasing water productivity. Area under horticultural plantations is increasing at exponential rate. The unproductive uplands and low productive midlands and lowlands are brought under fruit based horticultural plantations. For a profitable orchard enterprise, a well-planned irrigation system and efficient water management practice are of utmost importance. Horticultural sector, which includes vegetables, f lowers and fruits, has enormous potential for development owing to varying agro-climatic conditions in India. There is tremendous scope for increase in productivity and quality of horticultural crops, which is necessary to compete in this modern competitive world market. There are many production technologies available to increase the per unit vegetable production and also to increase its quality. One of the widely acceptable, reliable and cost- effective technologies is pressurized irrigation.

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.

Water melon is tender to frost and most of cultivars require relatively long growing season. Plant growth and fruit development are fallowed by higher temperature and abundant sunlight. Atmospheric humidity greatly regulates fruit and foliage diseases.

Taxonomy and Origin: Ealier it was classified as Citrullus Vulgaris Schrod. But in 1963 Thieret called attention to the correct name, C. lanatus (Thumb) Mansf. Africa is centre of origin of the genus. In 1857 David Living Stone, the famous missionary explorer found both bitter and sweet melons grown together in Africa and native people used them as source of water. Cultivation is prehistoric as there are pictures made in ancient Egypt. Early cultivation occurred in Mediterranean area and as far as India also and It was brought to USA by European colonist as early as 1629.

Irrigation water always contains some soluble salts irrespective of its source. The suitability of waters for a specific purpose depends on the types and amounts of dissolved salts. Some of the dissolved salts or other constituents may be useful for crops. However, the quality or suitability of waters for irrigation purposes is assessed in terms of the presence of undesirable constituents, and only in limited situations is irrigation water assessed as a source of plant nutrients. Some of the dissolved ions, such as NO₃^- are useful for crops.

Collection of water samples

A representative water sample (500 ml) is collected in a glass or polyethylene bottle, which should be properly washed/rinsed with the same water that is being sampled. Floating debris or any other contaminant should be avoided while collecting the sample. After proper labelling (e.g. source of water, date of collection, and type of analysis required), the sample should be sent to the laboratory without undue delay.
Some of the anions such as SO₄ and NO₃ may be quite low in irrigation waters. Hence, the large volume of the sample has to be first concentrated by evaporating it to about 100 ml in order to obtain their detectable amounts.

Water quality standards (Classification)

Some countries have established national standards and criteria for evaluation and classification of water quality. The classification of irrigation waters has been made according to one or more of the following criteria.

1.    Salinity or total concentration of soluble salts (EC)
2.    Sodicity hazards (SAR)
3.    Alkalinity hazards (RSC)
4.    Combined evaluation on the basis of EC and SAR by USSL diagram
5.    Combined evaluation on the basis of EC and Adj. SAR
6.    Combined evaluation on the basis of EC, SAR and RSC

Watermelon (Citrullus lanatus (Thunb.) Matsam. & Nakai, 2n = 2x = 22, family Cucurbitaceae, cross-pollinated crop) is grown commercially in areas with long frost-free warm periods. Three-fourths of the world production is grown in Asia, with China the leading country in production. Watermelon is a nutrient-rich food full of vitamins, minerals and antioxidants. It also contains niacin, thiamin, vitamin B-6, zinc, magnesium and many more nutrients. There are many health benefits to watermelon as it is low in calories so it promotes phyto-nutrients and anti-oxidants essential for the optimization of health.

At global level, China tops in watermelon production (79 million tons) with other countries falling far behind, namely, Turkey (3.9 million tons), Iran (3.8 million tons), and India (2.5 million tons). During 2017-18, India produced 2.5 million tons of watermelon from 0.1 million ha (1 lakh ha) acreage and thus Indian watermelon productivity is 25 tons/ha. Top five states having area more than 10,000 ha in India are West Bengal (17,000 ha), UP (14,000 ha), Odisha (12,000 ha), AP (11,000 ha) and Karnataka (10,000 ha).

Watermelon (Citrullus lanatus (Thunb.) Matsum and Nakai) is an important cucurbit crop throughout the tropical and subtropical regions of the globe. It is an annual creeping vine and native to the Southern part of Africa, most probably the areas around the Kalahari Desert. Presently, more than 1200 cultivars have been developed and are being grown in nearly 122 countries with tropical and subtropical climates. Watermelon is mainly valued for its ripe ‘pepo’ fruits which are consumed as fresh-cut dessert or as juice. The fruits are a rich source of carotenoids, minerals, phenolic compounds, flavonoids, vitamin C and Citrulline, a non-essential amino acid. The red colour of the watermelon flesh is due to the presence of lycopene, the content of which is 40% more than that of tomato. Besides, there is good variation available for f lesh colour ranging from red, pink, yellow, orange, white and green. Owing to the ability to prevent several chronic diseases due to the presence of pigments like lycopene, anthocyanin, carotene, xanthophyll etc., presently watermelon is also considered as a functional food. The exocarp (rind) is also consumed as stewed, pickled or stir-fried or may be used for the preparation of ‘tooty fruity’. Watermelon seeds are considered a good omen and are gifted during Chinese New Year in East Asia. The seeds are also used in the baking and confectionary industries as these contain a characteristic nutty flavour. The seeds are also rich in protein, vitamins as well as omega-3 and omega-6 fatty acids.

Watermelon, Citrullus lanatus under the family Cucurbitaceae (Chromosome number: 2n = 2× = 22) is an important and popular summer season crop of the USA, Middle east, Japan, Africa and India. Watermelon is primarily consumed fresh for their sweet, juicy and slightly grainy flesh and are often eaten as desserts. Watermelon is actually a nutrient dense food. It provides high levels of vitamins, minerals, andantioxidants particularly lycopene and relatively low in calories.
Origin, domestication and adaptation in India
The origin of watermelon was in tropical Africa perhaps in Kalahari Desert, now in Botswana. The progenitor species, Citrullus colocynthis is endemic to Africa. Wide variation of this progenitor species is also found in Rajasthan and Gujarat in India. Wild watermelon seeds have been found in Uan Muhuggiag, a prehistoric site in Libya that dates to approximately 3500 BC. Watermelon was domesticated in Africa and later it was introduced in India. From India it spread to Near East and Asia. The watermelon which was domesticated in Egypt by 2000 BC were not the sweet modern variety. The fruit flesh of wild watermelons is watery, but typically hard-textured, pale-coloured and bland or bitter. The familiar sweet dessert watermelons, C. lanatus, featuring non-bitter, tender, well-coloured flesh have a narrow genetic base, suggesting that they originated from a series of selection events in a single ancestral population.

ABSTRACT

Rose (Rosa hybrida Linn.) is universally acclaimed as the ‘Queen of Flowers’. But this woody plant is considered less amenable to in vitro culture as compared to herbaceous plants. This is due to the fact that the establishment rose explants is difficult due to heavy phenolic exudation. In the present study, this problem was solved by a very simple and cost effective method. The cut ends of the explant were sealed with wax after thorough sterilization. Ten different explant collection periods with 20 different hormonal combinations in MS culture medium were taken for establishment. The winter dormancy period (Mid- December) was considered best for explant collection and showed 85% survival. Amongst the hormonal combinations 5mg/l BA coupled with 0.05mg/l NAA was considered the best. The average number of leaves (7.5) and average shoot length (7.3 cm) was also highest in this treatment, 15 days after culture establishment.

In the preceding chapters, we embarked on a comprehensive journey through the realm of vegetables, covering a wide range of species that belong to different botanical and culinary groups. These chapters provided an indepth exploration of the characteristics, growth habits, and environmental requirements of various vegetables, as well as the effects of weather conditions on their productivity.
However, the diversity of vegetables is vast, and there are several other important species that were not covered in the earlier chapters. These vegetables may be regionally specific, possess unique characteristics, or have distinct environmental requirements. Despite their importance, they have remained outside the scope of our previous discussions.
This chapter aims to fill this knowledge gap by providing an overview of these additional vegetables, with a focus on understanding the impact of weather conditions on their growth, development, and productivity. By examining the effects of temperature, moisture, light, and other environmental factors on these vegetables, we can gain valuable insights into their cultivation requirements and optimize their production.
Through this chapter, we hope to provide a more comprehensive understanding of the vegetable kingdom, highlighting the diversity of species, their environmental requirements, and the strategies for maximizing their yields. By expanding our knowledge of these lesser-covered vegetables, we can promote their cultivation, conservation, and sustainable use, ultimately contributing to global food security and nutrition.

Weeds are unwanted and undesirable plants which interfere with the utilization of land and water resources and thus adversely affect crop production.

Classification of Weeds

Weeds can be classified in three different manner based on morphology, life cycle, habitat and origin.

1. DEFINITIONS

Various definations of weed have been proposed. Weed is defined as a valueless plant growing wild, especially one that grows on cultivated ground to the exclusion or injury of the desired crop. Weed means any undesirable or troublesome plant, especially one that grows profusely where it is not wanted. The weed have also been defined a plant considered undesirable. Weeds are commonly unwanted plants in human-controlled settings, such as farm fields, gardens, lawns and parks. A weed may be any plant that grows or reproduces aggressively, or is outside its native habitat. Some plants that often are considered to be weeds are Bermuda grass, creeping Charlie, dandelion, golden rod, poison ivy, ragweed, wild carrot, wood sorrel, nutsedge etc.

Weeds are unwanted and undesirable plants which interfere with the utilization of land and water resources and thus adversely affect human welfare. They can also be referred as plants out of place. Weeds rank first among different agricultural pests causing crop loss. About 30,000 species of weeds have been listed in the world, out of which 18,000 cause serious damage in different ways resulting in considerable loss to agricultural production.

The term weed can be described in many ways. In general, it is said that weed is a plant, which is not sown by the farmers or which is out of place. Weed is defined as the unwanted, undesirable plant, growing out of its proper place, which interferes with the utilization of natural resources, is prolific, persistent, competitive, harmful and even poisonous in nature and can grow in adverse climatic conditions.There are more than 30,000 species of weeds distributed world over, out of which 18,000 are noxious and cause serious losses. Around 250 species are causing serious economic losses. Weeds in orchards reduce crop yields by competing for moisture, nutrients, light and space. They also act as a host for insect pests and diseases. When they become large, they interfere with orchard operations as well as water bodies. There are some weeds, which are parasitic partially or completely on the host tree e.g. striga and loranthus, in mango.

INTRODUCTION

Control of weeds below economic threshold level in potato crop is a substantial component of crop management strategy for achieving optimum productivity. In our country, potatoes are raised eitherin assured irrigation or as rainfedcrop with comparatively heavy doses of fertilizers. Therefore, weedsarebound to become menaceduringactive cropgrowth period of this cropand theseundesired plants needs to be controlled in early stages of crop growth by adopting several techniques. Current scenario of crop production is different from past due to manyreasons. Farm holdings are becoming smaller day-by-day and majority of potato growers are small and marginal farmers. They have limitedcapacity for purchase of inputs and farm machines. They need economical, efficient and easier to adopt weed control technologies.Farm labour is also costly nowin many regions as they are migrating towards cities and industrial townships. This scenariobecomes more complex as weeds would be major challenge due to global warming, which is slowly changingclimatesof potato growingregions in India.Theconcern forenvironmentalissuesemphasizeuponadoptingsystems and integrated approach for managing weeds in such away that thesedo not reducethe potato and system productivity (CPRI, 2014).

Most of us consider weeds to be the troublesome, competitive, aggressive, undesirable, unsightly elements of the plant world. We hate weeds since desirable plants cultivated by us are deprived of food, water, sunlight and space by these plants. They can easily colonize an area and thrive even under non-ideal conditions of growth and may affect human welfare adversely. It is perhaps due to this that the saying, when weeds win all the people lose, has come into existence.

The terminology committee of the Weed Society of America gives the simple definition of weed as a plant growing where it is not desired. King (1974) in his book Weeds of the World observed that ‘‘a plant classed as a weed in one region where it has few, if any, uses may when growing in another region, possess some very valuable uses, or in few cases may actually be cultivated’’. For instance, Bermuda grass (Cynodon dactylon) is a highly troublesome weed in crop fields, but in village pastures, it is a much sought for forage grass. Quack grass (Agropyron repens) is a very good soil binding grass on erodable non-crop lands but it is a serious weed when it infests crop fields and orchards. Campbell (1923) considered weeds as ‘honest, independent competitors for food materials in the struggle for existence’. He pointed out that the term, weed has developed in the minds of people not according to specific qualities or by a definite concept in the mind of man, but by human caprice, e.g., corn is a cultivated crop, hence, desirable plant in a corn field. However, if a corn plant grows in a Soya bean field, it is considered a weed by the Soyabean farmer. Sometimes, two persons may differ about the weedy nature of a plant at the same place and time, e.g., water hyacinth (Eichhornia crassipes) is a weed for fisherman but it is a plant of aesthetic value for a city dweller.

Thus, a corollary to the above definitions of weed is that weeds are those plants, which grow out of their place, interfere with the utilization of natural resources, prolific, persistent, resistant, competitive, harmful and even poisonous in nature and can grow under adverse conditions.

Onion is highly vulnerable to weed competition because of its slow early growth, shallow roots, narrow upright leaves and limited canopy development. Weeds compete for light, water, nutrients and space while also harbouring pests and pathogens. Severe infestation during the critical competition period can cause substantial yield reduction. This chapter describes major onion weeds and evaluates cultural, physical, mechanical, biological and chemical control methods. Timely planting, suitable spacing, mulching, raised beds, manual weeding, mechanical tools, herbicides and biological agents are discussed. Integrated Weed Management is recommended as a smart approach combining complementary methods to improve weed control, protect soil health and sustain onion productivity.