eChapters

Sanger Method for DNA Sequencing

One necessity first know a little about the structure of DNA:

1. A segment of DNA, which is ordinarily double stranded, has a specific orientation, as it has a 5' (read as “5 prime”) and a 3' (“3 prime”) end. This can be simply thought of as a front and tail end to the DNA segment.
2. When DNA is synthesized in the lab, the two strands are separated and new bases are added to the 3' end-thus DNA is assembled from the 5' to 3' end.
3. DNA cannot be synthesized from scratch. A short piece of DNA, called a primer, is required for the reaction to begin.
4. Primers are designed such that they are able to bind to the target DNA, the binding of which is the initiator for DNA synthesis.

Abstract

Consumer now-a-days relies on manufacturing and processing standards, particularly to know what ingredients are present, due to dietary, nutritional requirements, or medical conditions (e.g., diabetes orallergies). Modified PCR and combination of PCR with other analytical tools have been successfully used for analysis of various parameters related to functional foods such as detection and quantification of beneficial as well as food borne pathogenic microorganisms, food allergens, raw material source, bioactive compounds, genetically modified foods. Multiplex PCR method has been found to be an efficient tool for simple, rapid, and reliable identification of Lactobacillus and Bifidobacterium in probiotic products. Food allergens like gluten, peanut, hazelnut etc. could be easily detected in foods using PCR, even if present in small quantities. BOX-PCR and PCR-DGGE analysis have been used for identification of bacterial diversity of a naturally fermented functional food (Enzyme). HPLC combined with real time -PCR were successfully used to quantify and analyse compounds of secondary metabolites like phenylpropanoid amides, which represent an important class of nutraceutical having strong antioxidant and chemotherapeutic effects in various transgenic tomato tissues. Detection of active compounds in natural plant products were successfully achieved using PCR techniques. In general PCR have gained more importance as it has high sensitivity, improved precision, wide dynamic range for quantification, genotype based and is quick method of detection and quality control of foods than traditional culture based methods.

Introduction Garden Pea (Pisum sativum L.) is a small, round, green seed that is commonly eaten as a vegetable. It is a legume, which means it is part of the same family as beans, lentils, and peanuts. Its chromosome number is 2n=14. Peas are typically eaten fresh, frozen, or canned, and are often used in soups, stews, and casseroles. They are a good source of protein, fiber, various vitamins and minerals. Peas can be grown in a garden or farm and it is considered a staple food in many countries. Origin and Distribution Garden peas have a long history of cultivation and have been enjoyed as a food source for centuries. The exact origin of garden peas is believed to be in Central Asia. The distribution of garden peas expanded as they were introduced to different regions and adapted to various climates. They were brought to Europe during ancient times and became popular as a staple crop in many countries. The cultivation of garden peas also spread to Asia, Africa, and the Americas through the process of exploration and colonization. In modern times, garden peas are grown globally in both temperate and cool climates.

Downy Mildew
Diagnostic Symptoms
• At first grayish white, moldy growth appears on the lower leaf surface, and a yellowish area appears on the opposite side of the leaf.
• Infected leaves can turn yellow and die if weather is cool and damp.
• Stems may be distorted and stunted.
• Brown blotches appear on pods, and mold may grow inside pods(Fig-2).
Etiology
Scientific Classification
Phylum :Heterokontophyta
Class : Oomycota
Order : Peronosporales
Family :Peronosporaceae
Genus :Peronospora

 

The disease is seen at 3-4 leaves stage. Scattered, irregular, yellowish patches appear on the upper surface of the leaves and stipules. On the corresponding under surface of these patches, a greyish violet fi ne cottony mildew growth is seen. Infected tissue soon dies and turns brown. The disease fi rst appears on lower leaves and later spreads to upper leaves.

The peach tree (Prunus persica L.) is a species of Prunus native to China that bears an edible juicy fruit called a peach. It is a deciduous tree growing to 4–10 m (13–33 ft) tall, belonging to the subfamily Prunoideae of the family Rosaceae. It is classified with the almond in the subgenus Amygdalus within the genus Prunus, distinguished from the other sub genera by the corrugated seed shell. Among the temperate fruit’s peaches require relatively less chilling temperature. Now peach is a commercial crop in Argentina, Austria, Canada, Chile, Europe, USA, China, India and Japan. In India, it grown in hills of Uttar Pradesh, Jammu & Kashmir, Himachal Pradesh, Uttar Pradesh and Punjab.

Cultivars/Varieties: Sun Red, Red, Nectarine, Kateroo, Flordasun, Florda gold, Sharbati, Maygold, Kanto-5, Stark Early Flame, Summerset, Early White Giant, Redglobe, Alexander, First Gold, Early Gold and Sweet Gold.

Uses

Peachs are grown both for dessert and processing purposes. It is also used for making wine. Peach fruit juice is a common drink. Peach kernel has high protein and its oil is used in food, cosmetics and pharmaceutical products. The cake after extraction of oil can be used for various purposes. Peach flowers and leaves are anthelmintic and purgative.

1. Introduction

The peach [Prunus persica (L.) Batsch] is an important fruit crop of temperate regions, all over the world. Important centers of commercial production usually lie between latitudes 30° and 45° North and South. At higher latitudes, minimum winter temperatures and spring frosts are the limiting factors. The peach flower bud is hardy and can tolerate minimum temperature of about -23 to -26° C. Its northern range is extended where minimum temperature are ameliorated by large bodies of water, as western continental seaboards, the great Lakes in the U.S.A. and Canada and the Caspian and Black seas of Eurasia. Mid continental areas are characterized by lower winter temperatures and usually more severe spring frost hazards. Most peach cultivars require 500 to 1000 chill hours below 7.2° C to foliate and bloom. At lower altitudes, the winter requirement is not met. The peach with its smooth skin mutant is known as nectarine. Nectarines can be used in the same way as peaches, and may be considered as substitutes for peaches.

Green peach aphid/peach leaf curl aphid : Brachycaudus helichrysi Aphididae

These are green aphids that suck the sap from growing buds. Leaf buds become weak and result in poor setting and premature fruit fall.
 
Blossom thrips : Thrips rhopalantennalis, T. flavus, T. florum, Haplothrips tenuipennis, Frankliniella dampfi : Thripidae

These are tiny, yellow, pale-brown and black slender insects seen within the flowers and flower buds. Adults and nymphs lacerate floral parts and suck sap resulting in brown spots. Infested flowers give sickly and faded look. Lesions cause flower fall, inferior fruits and loss in yield. Attack on tender leaves causes necrotic silvering, curling, deformation and withering.

1) Leaf Curl
Taphrina deformans
Disease Symptoms
• Initially yellowish to reddish areas appear on leaf blade of young leaves in the spring.
• These areas progressively thicken and pucker along the midrib causing the leaf to curl.
• Infected leaves often develop red to purple color. Later on white to silvery coating of spores develop on the upper leaf surface and the affected leaves become crisp and brittle.
• Finally, infected leaves abscise prematurely or may sometimes remain attached , gradually turning dark brown on severly infected trees.
• Fruit infection is characterized by irregular, raised, wrinkled and reddish lesions.
• Infected flowers and fruits drop rapidally(Fig-1).

The word persica, along with the “peach” itself and its cognates in many European languages, derives from an early European belief that peaches were native to Persia. Alexander the Great and his armies found the peaches in Persia and brought them to Greece. Most of the peaches grown in commercial orchards today are fruits that are harvested while too firm with a seed that clings to the pulp called a “clingstone” peach. The best flavoured peaches ripen soft and the seed easily separates from the edible portion, and these are called “freestone” peaches.

• Highly susceptible to waterlogging.
• Self-compatible in nature.
• Low chilling peach - <500 hrs chilling requirement.
• Red blush skins are caused due to anthocyanins.
• The yellow colour of peach is due to xanthophylls.
• Acid present - Malic acid
• Prunasin is the principal glycoside present in the pulp.
• Amygdalin is present in the seeds of peach.
• The oil content of peach seeds is 40-50%
• Prunus behmi is a natural hybrid of Almond and Peach.
• - Smooth skinned peaches (Prunus persica var. nucipersica) also called nectarine.
• Yellow fleshed peaches are ideal for table and canning purpose.

Genus : Prunus 
Species : persica Batsch
Family : Rosaceae
Chromosome No. : 2n = 16

The peach, Prunus persica (L) Batch is unique among the temperate fruits as it is adaptated to varied climatic conditions and it is for this reason that peach and its close relative the nectarine, in a short period has spread rapidly to different parts of the world. Peach is a tree of temperate zone, but has attained higher quality (fruit colour, taste etc.) in areas where the summer temperatures are relatively warm to hot. With the discovery of low chill types ‘Honey’ and ‘Peen to’ forms from southern China, peach cultivation has been spread to warm temperate regions of the world. Normally peach requires from 500-1000 hours of cold/chill hours below 7.2oC for growth and flowering in the spring. Peach history as a garden crop in China is well documented, and forms varying in flesh colour (white, yellow or red), free stone or cling stone, flower colour, large and showy flower type seen presently were also present at very early time i.e. the beginning of the present century.

4.1 Introduction

Peach is temperate and economically important fruit species and is in third position among temperate fruits after apple and pear. The peach, and its smooth skinned mutant, the nectarine, are primarily grown in temperate zones of the world. Peach belongs to the family Rosaceae and is native to China (Lurie and Crisosto 2005). Peach was also called as Persian apple and was probably carried from China to Persia (Iran) and, thus, peach quickly spread from there to Europe (Lurie and Crisosto 2005). In India, it is grown in the mid-hill zone of the Himalayas extending from Jammu & Kashmir to Khasi hills up to an elevation of 2000 m above mean sea level (Meitei et al. 2013). It is one of the most important stone fruits grown in Punjab, Haryana and the adjacent areas of Western Uttar Pradesh, Uttarakhand and Himachal Pradesh. Because of its refreshing, health promoting and delicious qualities, peach fruit is popular all over Northern India. There are many types of peaches. The free-stone types, which have melting yellow or white flesh, are usually consumed fresh and the second one, the cling-stone types with rubbery flesh, are used in processing; the nectarine, which is characterized by non-fuzzy skin, resulted from a mutation, and Peento, a flat peach with a saucer shape, is another variant. It is also a rich source of vitamin A, iron and proteins. Peaches are eaten fresh, canned or dried and are excellent sources of fibre, vitamins and antioxidants The peach kernel oil is utilized in manufacturing of a large number of cosmetics and pharmaceutical products. Nectarines, scientifically known as Prunus persica var. nucipersica, are commonly known as stone fruits which bears fruits similar to peaches but is smooth and lacks hairy fuzzy feature of peaches.

The fi rst symptom of disease appears in early spring soon after leaves come out of buds. Affected leaves become distorted and fold over as tips directed backwards. The whole lamina puckered except tip and blistered. In some leaves, part of leaf show distortion. Blistered portions are thicker, softer than the normal leaf blade. The affected areas remain green for a while and gradually become yellow and fi nally turn reddish-purple in colour. 

Peach (Prunus persica L. Batsch) belongs to the Prunoideae subfamily of the Rosaceae with other species collectively referred to as “stone fruits. Unusual in its subgenus, the peach is largely self fertile. There are at least 77 wild species of Prunus and most of them are found in Central Asia. Peaches include different types of varieties downy skin with freestone or clingstone (peach), smooth skin with freestone or clingstone (nectarine) (Bretaudeau and Faure, 1991). It is considered as favourite table fruit and highly valued for its taste, flavour and attractive colour. The fruits are rich source of sugars, vitamins and minerals and malic acid (1.2%). Peach fruit shapes vary from round to flat, beaked, skin colors vary from white to red or yellow, the flesh color white or yellow melting or non-melting types and it can be clingstone or freestone. Regions with warm to hot summers are produces highest quality peaches. It has a range of uses as fresh fruit for table purpose as well as processed product especially in sauces, slice production and canning. Peaches are highly ruminative and nutritionally rich crops for mild temperate to subtropical regions. Peaches are excellent sources of fiber, vitamins and antioxidants. The carbohydrates, organic acids, minerals and dietary fiber are among the major constituents of peaches, which contribute to the nutritional quality of both fresh fruits and the juices (Manzoor et al., 2012).

The pear or naspati (Pyrus spp) is a popular temperature fruit next to apples. It ranks high among sub-acid fruits as it contains less acid than almost any other fruit. Pear belongs to the genus Pyrus under the family Rosaceae and sub- family Pomoideae. The European pear (Pyrus communis) with a persistent calyx, fleshy pedicels and pyriform shape is different from Pyrus pyrifolia or Pyrus serotina (Asiatic pears) and are non-fleshy pedicels with apple shape.

It has been used as a food from time immemorial. The pear is a wholesome fruit and at par in importance with the apple. The flesh of the pear is, however, slightly harder than the apple, but it is juicier than the apple. Like the apple, it has few seeds. It grows on a comparatively large tree. It has generally yellow and brown colour. Sometimes, there is also a tint of red. It has several several varieties across the world.

It originated in mountainous reach of western China. The major pear producing countries are Italy, USA, Japan, Spain, France, Germany, Turkey and Australia. In India, it is mainly grown in Jammu & Kashmir, Himachal Pradesh and hills of Uttar Pradesh.

Cultivars: In India, Bartlett is widely grown in Kashmir. Kieffer, a cross between Pyrus communis and Pyrus pyrifolia, is popular in South India. In Punjab, the popular varieties ar Patharnakh, Le Conte, Smith and Kieffer.

1. Introduction

Pear is among the oldest of the world’s fruit crops, figuring in both Bible and the tales of Homer. They are by far the most important of the deciduous tree fruits, are widely grown in temperate and increasingly, in tropical regions, and figure prominently in world trade. The fruit is primarily grown for the fresh fruit market, which is much more remunerative than that for processing.

Pear (Pyrus communis, Rosaceaea family), is a deciduous fruit, grown under a wide variety of climatic regimes, ranging from cold dry temperature hilly conditions to warm humid subtropical conditions. It is grown in many places of India like Jammu and Kashmir, Himachal Pradesh, Karnataka, Tamil Nadu, Kerala, Utter Pradesh. Sandy pear plants were brought to Amritsar by travellers from China who settled at Harsha Chinna village near Amritsar about 2,500 years ago. The Kashmir valley represents one of the major Pear (Pyrus communis.L.) growing areas of the world. Pear was introduced in India from China. The time at which Pear was introduced to Kashmir is not precisely known, however Yukteshwar Kumar writes in his book “A History of SinoIndian Relations” that peach and pear came to India during the early years of the Eastern Han period (25 AD to 220 AD). This pre historic fruit has been under cultivation both in Europe and Asia for about 3000 years (Hedrick et al., 1921). Between 16^th and 18^th centuries, many European writers travelling Kashmir noted fantastic royal gardens of the Mughals, mentioning the abundance of peach, pear, plum and cherry trees, with fountains spouting cold, icy water. Pear (Pyrus communis. L), originating from the German word ‘peer’ meaning fruit, is a fascinating fruit steeped in rich history. This fruit is known as ‘tang’ in Kashmiri language. Low chill requiring pears are being cultivated in plains of North India. Cultivars requiring high chilling hours (900-1000) are cultivated at higher hills of Jammu and Kashmir, Himachal Pradesh and Uttarakhand. Majority of the Pear production is actually limited to Kashmir however, low chilling cultivars grow in subtropical regions.

Chinese pear (Pyrus pyrifolia) is a pear tree species native to China, Japan and Korea. The tree’s edible fruit is known by many names, including Asian pear, nashi or nashi pear, Korean pear, Japanese pear, Taiwan pear, sand pear or apple pear. In South Asia, the fruit is known as Nashpati. The tree is a popular symbol of spring in East Asia and is a common sight in gardens and the countryside. The European pear (Pyrus communis) is a species of pear native to Central and Eastern Europe and Southwest Asia. The European pear is one of the most important fruit of temperate regions.

• More tolerant to wet soils but less tolerant to drought than apple.
• Browning of pears is due to polygalacturonase activity.
• Major acid - Malic Acid
• Chilling - China Pear (Low chilling) - 150 hrs.
• European pear - 1200-1500hrs.
• Most commonly used clonal rootstock - Quince A cutting.
• Quince is scientifically - Cydonia oblonga origin - South-Eastern Europe and Asia minor.
• Quince is a monotypic genus
• Vigorous rootstock - Pyrus pashia
• Graft incompatibility is overcome by double grafting with old home or hardy varieties.
• In India, the open center system is common
• Training system modified central leader system

Genus : Pyrus 
Species : communis L.
Family : Rosaceae 
Chromosome No. : 2n= 34

Pear like apple is also a prehistoric crop and unlike apple its cultivation in Europe started much before that of apple at an early time. According to Homer (1000 B.C.) the ancient Greek said that pears were one of the “gifts of god’s”. Romans also enormously added to the knowledge of pear cultivation. Pliny in Rome had described 35 cultivars (23-79 AD). The variation in fruit characters described earlier match to the range of fruit characters which are found in presently grown commercial cultivars. In Europe for its buttery soft texture and distinct aroma many consider European pear as the most detectable of all temperate fruits, while the Asian pears for their firm crisp texture and juiciness are preferred more in China and Japan – their native place. Pears are readily consumed as fresh, dried, cooked or as preserves or to make perry and pear wine.