eChapters

Fresh fruits are an important component of our diet since they provide essential nutrients like minerals and vitamins and are often attractive to the consumer because of their taste, texture, colour, aroma and flavour. Fruits of different species are botanically different, and they may be derived from various parts of the flower, including the pericarp, mesocarp and receptacle. Growth of fruit tissues is initiated shortly after fertilization and accompanied by the accumulation of food reserves donated by the parent plant. Fruit ripening corresponds to a number of physiological, structural and biochemical changes, which make the fruit attractive to the consumers. These changes include physical changes, viz. the changes in colour, texture, taste, aroma and flavour, and the metabolic changes such as changes in the level of enzymes and gene expression. The varieties of mechanism, which exist in different fruits to bring about a series of these changes to make them attractive for consumption, have been summarized in Table 9.1.

Because of the variety of ways in which these quality attributes are generated, there are significant differences existing in enzymes involved in ripening of different types of fruit. Once initiated, these physiological and biochemical modifications continue until the fruit is in peak condition for consumption. If the fruits are not harvested at appropriate stage of maturity, these changes continue and make them more susceptible to mechanical damage, infection and senescence. Since harvesting fruits at right stage of their maturity is critical, it is important to understand the biochemistry of fruit ripening process fully. This chapter will highlight the biochemical and metabolic changes involved during fruit ripening to make the fruit acceptable for potential consumers. Some of the possible genetic manipulations, which can be done to delay the onset of these ripening related changes, are given in later part of the chapter.

In addition to pathogenic diseases, numerous abiotic disorders may also arise during growth, development and post-harvest storage of solanaceous vegetables. The physiological disorders of vegetables that have been included in this chapter are directly or indirectly associated with genetic, cultural, nutritional, physiological and environmental factors, and in most of the cases, the definite cause of disorder is not well understood due to the association of numerous factors together. These disorders may be related to colour, shape and form/condition of the produce. The genesis of physiological maladies was earlier poorly understand due to complexity in their characteristic symptoms but at present is relatively more transparent. The characteristic symptoms of abiotic disorders discussed below have not been attributed solely to a single agent or to a single cultural or environmental factor. The environmental factors correlated with the incidence of these disorders include high light intensities and low or high temperature of that growing area. For many abiotic disorders, very limited research work has been done, and the causes are poorly understood both in terms of why cultivars differ in susceptibility and why certain environmental factors predispose the plants or parts of the plant to the disorder. The growers feel concerned with the incidence of abiotic disorders as these cause huge economic loss. Therefore, the control of these abiotic disorders is essential for profitable production of solanaceous vegetable crops. In this chapter, emphasis has been given on practical aspects of diagnosis and potential control measures.

Fruits provide a suitable environment for seed maturation and often a mechanism for the dispersal of mature seeds. By anatomical definition, fruit is a mature ovary, and therefore, includes carpel tissues in part or in whole. However, many fleshy fruit species develop mature fruit tissues by including extra-carpellary floral components. The examples include strawberry, pineapple, mulberry and pome fruit (apple, pear, etc.) in which the receptacle, bracts, calyx and floral tube (the fused base of floral organs), respectively constitute majority of mature fruit tissues. Even species with fruit derived from carpel tissue exclusively can display a range of developmental programs, spanning the relatively uniform single expanded carpel or drupe of stone fruit to the differentiated carpel tissues, giving rise to the peel (flavedo) and multi-carpel flesh as observed in citrus and banana. Although genetic selection of agriculturally valuable fruits is being done since centuries but most of the information about how fruits develop, how this development is coordinated with embryonic development and seed formation and the molecular, cellular and physiological events that control fruit growth and differentiation are still lacking. In the following sections, the various aspects controlling fruit setting and development have been discussed.

Flowers are the reproductive structures of Angiosperms. The apical shoot meristem of the vegetative plant continues to produce new leaves and vegetative buds, which may develop into branches, but after sometime, the meristem, instead of producing leaves and branches, becomes transformed into specialized reproductive structures called flowers. The transformation of vegetative shoot apex into re-productive structure is called flowering. The process of flowering is controlled by two main important environmental factors, i.e., (i) the duration of light received by the plant called photoperiod and (ii) the low temperature treatment given to the seed or the plant referred to as vernalization (Figure 6.1).

The transition from vegetative to floral meristems in higher plants is programmed by the coincidence of internal and environmental signals. The timing of floral transition has a direct impact on reproductive success. One of the most important environmental factors that affect the transition is the change in day length (photoperiod). Classical experiments imply that plants monitor photoperiods in the leaf and transmit that information coded within an elusive signal dubbed florigen to the apex to reprogram development. Recent advances in Arabidopsis research indicate that the core of the day-length measurement mechanism lies in the circadian regulation of CONSTANS (CO) expression and the subsequent photoperiodic induction of the expression of FLOWERING LOCUS T (FT) gene, which might encode a major component of florigen. The florigen paradigm was conceived in photoperiod-sensitive plants; nevertheless, it implies that although it is activated by different stimuli in different flowering systems but the signal is common to all plants. Flowering time, the major regulatory transition of plant sequential development, is modulated by multiple endogenous and environmental factors.

Respiration is the oxidative breakdown of complex substrate molecules such as starch, sugars, and organic acids normally present in plant cells to simpler molecules such as carbon dioxide and water. Concomitant with this catabolic reaction is the production of energy and intermediate molecules that are required to sustain the myriad of metabolic reactions essential for the maintenance of cellular organization and membrane integrity of living cells. Since respiration rate is so tightly coupled to the rate of metabolism, the measurements of respiration provide an easy non-destructive means of monitoring the metabolic and physiological state of tissues, e.g., the events of senescence and ripening are often signaled by abrupt changes in respiration.

Maintaining a supply of high-energy compounds like adenosine triphosphate (ATP), nicotinamide adenine dinucleotide (NADH) and pyrophosphate (PPi) is a primary function of respiration. Nicotinamide adenine dinucleotide plays very important role in mitochondrial matrix (Moller and Ramusson, 1998). The overall process of aerobic respiration involves regeneration of ATP from adenosine diphosphate (ADP) and inorganic phosphate (P_i) with the release of carbon dioxide and water. If glucose is used diphosphatas substrate, the overall equation for respiration can be written as follows:

Photosynthesis- the word photo refers to light and synthesis means preparation. Thus, photosynthesis is the process by which the green plants use light energy of the sun to synthesize carbohydrates. Carbohydrates like simple sugars (glucose) can be stored as starch.

The green plants are eaten by the herbivores, which in turn are consumed by carnivores. Ultimately, the decomposers derive their nutrition from the dead plants and animals. Thus, all organisms are dependent directly or indirectly on green plants, which synthesize food by photosynthesis. Thus, photosynthesis is the most important life sustaining process of nature (Calvin, 1976; Emerson and Arnold, 1932). Photosynthesis is a series of biochemical reactions, which can be essentially summarized as follows:

The capacity to reproduce is one of the most important characteristics of all living beings. Reproduction is a process of producing offspring and is aimed to preserve individual species. This is known for self-perpetuation. There are several modes of reproduction, which vary from species to species, in available conditions. All the reproductive methods of plants are broadly classified into two types, i.e., (i) asexual reproduction (apomixis) and (ii) sexual reproduction (amphimixis). In asexual reproduction, the new individuals are produced by any means other than the fusion of sex gametes. In sexual reproduction, the gametes from male (androecium) and female organs (gynoecium) of the flower are fused to produce a zygote (Schranz et al., 2005; Rodrigues et al., 2008). Amphmixis and apomixis are the two sides of same coin (Curtis and Grossniklaus, 2007).

Plant body consists of numerous microscopic box like components called cells. The word cell has been derived from the Latin word cellula, meaning a small room. The descriptive term for this smallest living biological structure was coined by Robert Hooke in a book he published in 1665. When he compared the cork cells, he saw through his microscope to the small rooms monks lived in. The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life, which is classified as a living thing and is often called the building block of life (Maton et al., 1997). It is defined as a mass of protoplasm surrounded by a membrane- the plasma membrane- within which complicated chemical reactions are going on.

• Fruit and vegetable processing was 1^st started in organized manner in 1857
• Canning of fruit and vegetable started in 1927
• Needham (1729) 1^st time explained: cause of spoilage of stored food
• Nicholus Appert (1804) 1^st preserved the food in glass containers
• Cooking of food by means of preserve started by Papin in 1861
• In India, 1^st fruit and vegetable processing industry was established in 1935 at Mumbai
• In 1950, CFTRI was established at Mysore
• FPO: Food Product Order was passed by Govt of India in 1955
• 1^st fruit preservation and Canning Institute was established in 1949 at Lucknow

Those plants which are completed their life cycle in a season or a year, is called annuals. Thre are many types of annuals.

1. On the basis of seasons:
   1. Rainy annuals: Balsam, Cock’s comb, Amaranths, Gaillardia, Torenia, Gompherena etc.
   2. Summer annuals: Zinnia, Kochia, Tithonia, Sunflower, Cosmos, Coreopsis.
   3. Winter annuals: Remaining annuals.

• Botanical name: Papavera somnifera
• Family: Papaveraceae
• Origin: Europe
• Useful part: Fruit/Capsule
• Chemical content: Morphine, Narcotine, Codine
• Flowering time: 95–115 days after sowing
• Capsule maturity: 15–20 days after flowering
• Uses: It is also called “God of sleep”. It is used in Painkillar, hypotonic effect and cure to leukaemia
• It is a licence crop and grow in Aari
• One aari equals to 100 m²
• Seed rate: For broadcasting: 7–8 Kg/ha

  For line sowing: 4–5 Kg/ha

• Thinning is important cultural practices.

• Botanical name: Lycopersicon esculatum
• Family: Solaceae
• Origin: Peru/Mexico
• CN: 24
• India is the second largest producer of tomato in the world after China followed by Turkey, USA and Italy.
• Highest producing state:Orrisa > Andhra pradesh > KN
• Highest productivity: KN > MH > Assam
• Tomato is universally treated as ‘Protective food’.
• The total sugar content is 2.5% in ripe fruit.
• Vitamin-C: 16–65mg/100g of fruit weight.
• The total amino acid is 100–350mg/100g of fruit weight.
• Processed product of tomato like puree and paste have great demand in export.
• Tomato is a herbaceous, annual to perennial plant.

MANGO

(Mangifera indica, Anacardiaceae; 2n=40, Origin; Indo-Burma)

• India contributes 56% of total mango production in the world
• Highest productivity in the world– Venezuela
• Pollination: House fly (Musca domestica)
• The flower is hermaphroditic with male and female flowers in the same flower panicle.
• Inflorescence-Panicle
• Hybridization work was started by Burns and Prayag in 1911 at Pune in MH.
• Caging technique of breeding was used in Mango by Dr. R. N. Singh.
• In mango, only 0.1% flower develops fruit to maturity.
• The optimum temperature range for its growth and development is 24°C to 27°C.
• It can tolerate up to 48°C during fruit development with regular irrigations, which improve fruit size, quality and maturity.
• For flower bud differentiation, suitable temp is13°C–19°C.
• Mangoes are highly susceptible to low temperature injury/Chilling injury.

Biofertilizers

Definition: Biofertilizers are defined as preparations containing living cells or latent cells of efficient strains of micro–organisms that help crop plant’s uptake of nutrient by their interaction in the rhizosphere when applied through seed or soil. They accelerate certain microbial process in the soil which augments the extent of availability of nutrient in a form easily assimilated by plants.

Types of biofertilizers

There are some types of biofertilizers:

1. Nitrogen fixing biofertilizers
2. Phosphorus solubilizing biofertilizers
3. Phosphorus mobilizing biuofertilizers
4. Biofertilizers for micro–nutrients
5. Plant growth promoting rhizobacteria

Mulching

Definition: It is the practice of covering the soil with loose extraneous matter is known as mulching.

Types of mulching

There are two types of mulching:

1. Organic mulching
2. In–organic mulching
3. Organic mulching: In this mulching the open soil is put under loose cover of straw, hay, crop residue, leaves, saw dust etc.
4. In–organic mulching: In this mulching the open soil is put under plastic, film, metal foil, sand, stone etc.

Plant growth

Definition: 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.

Plant development

Definition: The qualitative changes such as germination of seed, formation of leaves, flowers and fruits, falling of leaves and fruits is referred as developement.

Phytohormones

Definition: These are the organic substance or hormones produced by plants which in low concentrations regulate plant physiological process. It is synthesized in one part of plant and translocated to other parts. These are endogenous substance means naturally occurring in the plant.

Weed

Definition: “Weed is an unwanted plant growing where it is not desired.” – Jethro Tull

Commonly noticed weed species in fruit orchard:

• 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.
• Monocot weeds (Narrow leaf/Grasses): Cyprus, Cynodon, Poagrass, Rye grass, Quackgrass etc.
• Dicot weeds (Broad leaf weeds): Dandelion, Chenopodium spp., Parthenium, Solanum, Euphrobia spp., Ground ivy etc

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.

Soil fertility

• Soil serves as a source of nutrient required for the growth and development of plant. This characteristic of soil is called soil fertility.

Management practices

• Improved organic matter and soil moisture in soil, favours the growth of micro-organism beneficial for maintaining fertility of the soil.

Manures

• It is an organic waste material of plant and animal origin. It is used improvement of soil fertility. There are major 2 types of manure

1. Bulky organic manures
2. Concentrated organic manures