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Bottle gourd (Lageneria siceraria) 2n=2x=22 is also known as white flowered gourd. Most important vegetable of ancient China.
 
Origin : According to De Candolle (1882) Bottle gourd has been found in wild form in South Africa and India. However, Cutler and Whitaker (1962) are of the view that probably it is indigenous to Tropical Africa on the basis of variability in seeds and fruits. This species appear to have been domesticated independently in Asia, Africa and the New world (Heiser, 1973).
 
Botany: It is monoecious, annual vine with soft pubescence. Leaves are cordate ovate to reniform-ovate, Flowers are white, solitary, open at night and has hairy ovary. Fruit shape is cylindrical, oval egg shaped, club shaped, round and other shapes also appeared.

Genetics of Important Traits

Bitterness: Single dominant gene (Path and Singh, 1950)

Fruit colour: Monogenically controlled (Kalloo, 1993)

Two major genes are involved for fruit shape (Path and Singh, 1950). Single gene for fruit colour involved (patchy v/s white) and reported by Path and Singh (1950). Monogenic recessive inheritance for andromonoecious sex form is reported by Singh et al. (1996). Hermaphrodite sex form is characterized by long corolla (3.5-4.5cm instead of 2.5-3.5cm in normal). In hermaphrodite condition fruits bears prominent blossom scar.  Long fruit conditioned by AA genotype and Round fruit is due to aa genotype where Partial dominance is reported (Kushwaha, 1996).

Bottle gourd, Lagenaria siceraria under the family Cucurbitaceae (Chromosome No: 2n = 2× = 22) is commonly grown vegetable crop of India, Africa, Central America and other warmer regions of the world. Tender fruits are widely used as cooked vegetables in a number of ways. Bottle gourd is a good source of vitamin C and zinc that may offer several skin benefits. It also contains minerals like calcium, magnesium, iron, and zinc. Its dietary fibre enhances gastro-intestinal health and promotes bowel movements and prevents constipation.
Origin, domestication and adaptation in India
It is the only crop known to have been cultivated in pre-Columbian times in both the Old and New World. Bottle gourd is indigenous to the tropical Africa. It has
bihemispheric distribution in Africa, the old world and America, the new World. Its utilization by man is about 16,000 years in the Old World and 12,000 years in the New World. It was independently domesticated in the two hemispheres. It was one of the world’s first cultivated plants grown not primarily for food, but for the use of hardshelled fruit as containers. The apparent wild plant produces thinner-walled fruit that, when dried, would not endure the rigors of use on long journeys as a water container. Today’s bottle gourd may owe it’s tough, waterproof wall to selection pressures over its long history of domestication. The bottle gourd was theorized to have drifted across the Atlantic Ocean from Africa to South America.

Horticulture includes variety and diversity of crops. Thus, it can be divided into several branches depending upon the crops it deals with. Following are the branches of horticulture.

1. Pomology: The term pomology is a combination of two Latin words pome i.e. fruit and logos i.e. science. Recently it has been designated as ‘Fruit Science’. It deals with the study of fruit crops. It includes all aspects of fruit crops e.g. importance, uses, origin and distribution, area and production, soil and climate requirement, botany, nursery raising, cultivation practices, plant protection measures, stage and methods of harvesting, post-harvest handling, marketing, export, import, etc. e.g. mango, banana, citrus, grape, apple, peach, pomegranate, fig, etc.
2. Olericulture: The term olericulture is also derived from the Latin word. Cultivation of vegetable crops. Recently it has been designated as ‘Vegetable Science’. Vegetables are said to be herbaceous plants of which edible plant parts are used for consumption either cooked or salad. It may be stem, root, leaf, flower, etc. It also includes all aspects of vegetable crops e.g. importance, uses, origin and distribution, area and production, soil and climate requirement, botany, nursery raising, cultivation practices, plant protection measures, stage and method of harvesting, post-harvest handling, marketing, export, import, etc. e.g. tomato, brinjal, chilli, cucumber, red pumpkin, watermelon, cabbage, cauliflower, etc.
3. Ornamental Horticulture: It includes various groups of ornamental plants used to decorate in-door and out-door areas. Ornamental horticulture is the study of growing, arranging and tending decorative plants and flowers. It is further divided into.

Breadfruit (Artocarpus altilis) belongs to family Moraceae. The Latin name is derived from Greek words (artos = bread, karpos = fruit), and altilis meaning ‘fat’. Baked or roasted in a fire, the fruit has a starchy texture and fragrance, reminiscent of fresh baked food.

Breadfruit is an important staple crop and component of traditional agro-forestry systems in the Pacific for more than 3,000 years. This species originated in the South Pacific and spread throughout Oceania by intrepid islanders settling the numerous islands of Melanesia, Micronesia and Polynesia. Due to efforts of Captain Bligh and French voyagers, a few seedless varieties from Polynesia were introduced to the Caribbean in the late 1700s. These gradually spread to other tropical regions. Breadfruit is now grown in close to 90 countries.

Introduction

Global food productivity will have to rise significantly to satisfy an expanding world population. Increased vegetable production is one option towards the efficient conversion of natural resources into food stuffs. As a group, vegetables are a diverse range of herbaceous plants that do not belong to any particular botanical species, genus or family. Individual members may be at various stages of domestication. Vegetables are typically annual herbaceous species, whose plant parts (leaves, stems, flowers, fruits, roots or tubers) are consumed as fresh or as cooked product, and as an additional source of vitamins, minerals, fibre, phytochemicals, protein and/or calories. Health benefits are also claimed for some vegetable species, mainly due to antioxidant activity and capacity to scavenge free radicals.

Domesticated plants have been fundamentally altered from their wild relatives; these species have been moved into and adapted to new environments. They have become dependent on the farmer’s hand and they have been reshaped to meet human needs and wants. Modern crops are the results of thousands of years of these evolutionary processes. Like all biological evolution, crop evolution involves two fundamental process; the creation of diversity and selection (Harris and Hillman, 1989). Crop evolution is distinguished by two types of selection; one natural and another artificial or conscious. These evolutionary processes must continue in order for agriculture, a living and evolving system to remain viable.

In the hands of plant breeder’s sexual hybridization is a powerful tool for producing superior plants by combining characters distributed in different members of a species or different species of a genus. Genetic variability within the species has been efficiently utilized by breeders in their efforts to improve crops. However, the existing variability in a breeding population may not be sufficient for modern plant breeding purposes, and thus great efforts have been made to broaden the existing gene pool of crops through utilization of wild germplasm.

The current status of advances in fruit breeding is through the development of different scientific approaches augmented by ever-increasing knowledge and application of genetics, statistics and biotechnology. These innovative approaches very specific for a species in most of the cases, are the major tools of the fruit breeders to tackle the different objectives of fruit improvement programme at present Fruit improvement is a very slow process due to the long generation cycle varying from species to species, thereby reducing the chances of exploiting genetic recombination. Besides this factor, most of the fruit species are either highly heterozygous or polyploidy in nature. Due to this reason the asexual propagation of fruit plants is a conventional means while wide segregation occurs upon sexual reproduction. Such expectation is not unlikely because the types selected as commercial varieties are definitely to be vigorous ones, and a positive correlation exists between vigour and heterozygosity.

This discussion on breeding of fruit plants involves different aspect of the species concerned is so essential as well as fundamental that discussion of them must procede any consideration of breeding methods themselves. The plant species are grouped into two-self-pollinated and cross-pollinated. These two groups have emerged on the basis of pollination mechanism which plays significant role in the method of breeding application. To emphasize the difference in the reproductive systems of these two groups one should know the details about floral biology, mechanism of pollination control, reproduction by asexual and sexual means and self and cross-pollinated plants.

Introduction

Stress is any unfavorable condition for a plant’s normal growth and development. In the case of crop plants, such adverse conditions are caused by biological (biotic) and non-biological (abiotic) environmental factors. Abiotic stress is the negative impact of non-living factors on living plants in a specific environment. Usually, abiotic stress is unavoidable, and we can only go for its management.

The most basic stresses include:

• Extreme (high/low) temperatures

• Soil-chemical properties

• Water deficiency

• Excessive moisture

• Element toxicity or deficiency

Diseases of plants are produced by a variety of organisms from plant and animal kingdoms viz., fungi, bacteria, viruses, nematodes and insects. The diseases reduce total biomass (dry matter) production and consequently yield of the crop by general stunting, damage to the leaf tissues, fruits and seeds or by killing the plants. The degree of damage would depend upon the intensity of infection but both need not be proportional. One serious effect of disease is the disappearance from cultivation of otherwise excellent but susceptible varieties.

Vegetable crops have been found to be highly susceptible to biotic stresses from the disease causing microorganisms and insects-pests. The ability of pathogen and insect-pests to attack and proliferate in the host plant is highly specific. There are wide differences in the host plants in response to the attack by pathogens and insects. Although control of the diseases and insects by the use of chemicals is possible to certain extent but indiscriminate use of fungicides or insecticides over the crop has several disadvantages. Besides increasing cost involved in chemical control, residual toxicity of the chemicals such as fungicides, antibiotics and insecticides in food chain and development of resistance against pathogens and insect-pests to different chemicals are serious problems.

Genetic improvement of host plants conferring resistance to diseases and insect-pests is considered to be the best approach in the management of diseases and insect-pests, and this is more particularly true in case of vegetable crops. Indiscriminate use of chemicals in the vegetable sector has led to health hazard. This has resulted in switching towards organic vegetables. However, cost of production of organic vegetables naturally will not permit the common people to consume these products. Therefore, the best option is to induce resistance in the host varieties. The resistant varieties could in turn be an important component in the organic vegetable farming, thereby reducing cost of production to certain extent.

Vegetable crops are highly susceptible to biotic stresses incited by different diseasecausing micro-organisms (fungi, bacteria, phytoplasma, virus), insect pests, nematodes, arachnids and weeds. In contrast to abiotic stresses caused by the environmental factors such as drought, heat, soil salinity, alkalinity, etc., biotic stress-causing agents directly deprive their host of its nutrients leading to reduced plant vigour and, in extreme cases, death of the host plant. In vegetable crops, different biotic stresses are the major cause of pre- and post-harvest losses.
Indiscriminate use of chemicals for the control of diseases, insect pests and nematodes has several disadvantages particularly, increasing cost involved in chemical control, residual toxicity of the chemicals (fungicides, antibiotics, insecticides) in food chain and development of resistance against pathogens and insect pests to different chemicals. Management of diseases and insect pests involve the use of resistant varieties and integration of cultural and chemical control measures.

High temperature stress
Abiotic stresses either individually or in combination cause morphological, physiological, biochemical and molecular changes that adversely affect plant growth and ultimately yield. The major forms of abiotic stress plants are exposed to in nature are heat, drought, cold and salinity. Of these abiotic stresses, heat stress has an independent mode of action on the physiology and metabolism of plant cells. High temperatures above optimal have generally damaging effects on plant development which has led to the prediction that Global warming have a negative effect on plant growth. High temperature regimes may cause severe yield reduction leading to even famine. High temperature stress has wide range of effects on plant in terms of physiology, biochemistry and gene regulation pathways. The susceptibility to high temperatures in plants varies with the stage of plant development and genotype.
Mechanisms of heat tolerance
Heat tolerance is generally defined as the ability of the plant to grow and produce economic yield under high temperature conditions. Several plant physiological parameters and mechanisms that contribute to heat tolerance in the field include:

Plant abiotic stresses are external and nonliving factors that have harmful effects on plants. A non-living factor must exert influence on the normal range of environmental variation to adversely and significantly affect the plant performance or the physiology of the organism. Abiotic stresses are the most harmful factors affecting the growth and productivity of crops worldwide, resulting in a yield reduction ranging from 10% to 100%. They are most harmful when occurring together with other abiotic stresses and their effect in yield will only worsen with the climatic changes experienced now and expected to be more severe in the future.

29.1 Introduction

An environmental factor that interferes with the complete expression of genotypic potential of a crop is called stress. The stresses may be biotic (pathogens, insect-pests, etc.) or abiotic. The main abiotic stresses are drought, mineral deficiency/toxicity and heat or cold. The losses due to abiotic stresses can be minimized by:

Crop management: The degree of stress can be reduced by suitable agronomic/soil management practices, e.g., irrigation to relieve drought stress, soil amendments to reduce salinity.

Development of resistant cultivars: This offers the cheapest, easiest to apply and most eco-friendly approach to reduce losses due to any stress.

Indirect breeding: Evaluation of materials under stress often helps in identification of a resistant line that may become an important commercial cultivar.

???????Direct breeding: It is deliberate breeding of materials for stress resistance. When a genetically variable material is grown under the stress environment, selection can be based on survival, yield and other traits contributing to stress resistance.

Biotic stresses include diseases and insect pests which cause serious damage to the crop plants and ultimately yield loss. Biotic stresses can be listed as follows:

• Diseases caused by pathogens which include fungi, bacteria, and viruses
• Insects
• Nematodes
• Parasitic weeds

Another category of stresses are called as abiotic stresses which are caused by environmental factors as:

• Water stresses (water logging, drought)

28.1 Introduction

The stress that is caused by biological agents or factors such as diseases, insect-pests and parasitic weeds is called biotic stress. The term disease can be broken into two words: “dis” (means negative, reverse or opposite) and “ease” (means comfort, or freedom from pain or discomfort). Hence, plant disease can be defined as any harmful alteration from the normal functioning of physiological processes. Diseases may be bacterial, fungal or viral. A wide range of insects infests various crop plants. The extent of damage caused to crop plants by various organisms is usually in the order fungi > bacteria > viruses > nematodes = insects. But the relative importance of these organisms varies to a great deal in different crops. Breeding of cultivars resistant to diseases and/or insect-pests is the cheapest, safest and most dependable means of limiting the losses due to them. Resistant cultivars form an important component of integrated management of diseases and insect-pests.

28.2 Breeding for Resistance to Biotic Stresses-Diseases

Agrios (1970) has defined disease as: “Disease is a series of invisible and visible responses of plant cells and tissues to a pathogenic microorganism or an environmental factor that result in adverse changes in form, function or integrity of plant and may lead to partial impairment or death of the plant or its parts.” The organism causing disease is called pathogen, while the plant affected by the disease is called host.

The principles underlying breeding for resistance to diseases are much the same as for other characters, except for one important difference, i.e., the diseases caused by pathogens are the product of interaction between two genetic systems, that of the host and that of the parasite. Both systems are capable of variation and evolution and affect the interaction between host and pathogen. Here the breeder is required to deal with the heritable traits of both the host plant and the pathogens invading it.

Vegetables are considered protective foods and play an important role in human nutrition. These help to combat malnutrition and also diversify diets with variety of colours. The compounds imparting various colors to the vegetables are important antioxidants that also help to combat degenerative diseases like cancer. Over the years, vegetable sector has made an appreciable progress in terms of production and productivity and emerged as the better option to diversify agriculture, generate employment and enhance farmers’ incomes. The worldwide production of vegetables has doubled over the past quarter century and the value of global trade in vegetables now exceeds that of cereals.

Globally, India ranked second in vegetable production and contributed 15.8 and 14% to global vegetable area and production, respectively. The production of vegetables in India is estimated to be 212.91 million tonnes in the year 2022-23 compared to 209.14 million tonnes in the year 2021-22. India ranked first in production of okra in the world (73% of world production) and second in brinjal (27.55%), cabbage (13%) and tomato (11%). The major vegetable growing states in India are West Bengal (14.1%), Uttar Pradesh (11.4%), Bihar (9.3%), Madhya Pradesh (8.0%) and Gujarat (7.1%). Vegetables are especially important crops for farmers with small holdings because an appreciably higher income per hectare can be generated by growing vegetables than from conventional staple crops (Genova et al, 2006). However, vegetables are generally considered more vulnerable than staple crops to stressful environmental conditions including extremes of temperatures, drought, salinity, alkalinity, water logging, mineral nutrient excesses and deficiency (Chinnusamy et al, 2005). These environmental stresses are likely to be exacerbated by the prevalent climatic changes in many parts of the world.
Among environmental factors, soil salinity stress is one of the main factor reducing production and productivity of vegetables in arid and semi-arid regions where irrigation water has excessive salt and annual rainfall is low. In India, about 6.73 million ha of land (~2.1% area of the country) is salt affected, out of which 2.96 million ha is saline and 3.77 million ha is sodic (Arora & Sharma 2017). About 75% of salt-affected areas exist in four states, i.e., Gujarat, Maharashtra, West Bengal, and Rajasthan (Mandal et al., 2018).

INTRODUCTION

India has emerged as second highest producer of potato in the world, after China. The crop has been identified as the most important crop for ensuring food security for the developing countries, and a highly nutritious food providing more calories, vitamins and nutrients per unit area of cropped land than any other staple food. The crop has witnessed phenomenal increase over the seven decades of potato research in India. For a crop which was introduced in the country only in the early 17^th century, and was neither adapted, nor its staple food, the remarkable increase in potato production and productivity is an exceptional achievement of breeding this temperate introduction into the present day potato cultivars.

BREEDING REQUIREMENTS

The table potatoes introduced in India were adapted to long photoperiods of up to 14 hours and crop durations of 140-180 days allowing them to be cultivated only in the hilly regions of India. The unique and diverse agro-climatic condition of the country, comprising of contrasting conditions in the Indian plains, where potato could be grown in the winter months necessitated breeding efforts to develop the potato varieties suitable for the sub-tropical plains and the other potato growing regions. The winters in sub-tropical plains have short photoperiod (with about 10-11 hours sunshine) and the crop duration is limited to 90-100 days because of short and mild winter. Further constraints on photosynthetic activity due to early morning fog, posing a strong limitation on tuber bulking. This is followed immediately by a long hot summer period, which coincides with the post-harvest storage period of potato, creating challenging storage problems. The rapid degeneration of seed stocks, with concomitant decrease in yield due to accumulation of viral diseases and tuber storage and utilization in hot and humid climate thus needed to be addressed, in priority. Besides, these southern, north Bengal and Sikkim hills and the plateau offer agro climatic area specific problems related to the biotic and abiotic stresses prevalent in the regions. Moreover, the unique reproductive biology of the plant made it possible to flower only under the long day conditions of the hills, where hybridization was initiated at Kufri (Shimla), Himachal Pradesh. However, during the initial years, it was not possible to evaluate the breeding progenies in the warmer sub-tropical plains due to the quick degeneration of hill bred progenies and dormancy of hill potatoes.

Important breeding methods can be classified as follows:
    1.    Introduction
    2.    Selection
    a.    Mass selection: Done in self pollinated crops, cross pollinated crops and dioecious crops.
    b.    Individual plant selection: Done in self pollinated crops, cross pollinated crops (line breeding) without control of pollination, artificially self pollinated lines, dioecious plants and clonally propagated lines.
    3.    Hybridization
    a.    Crossing in self pollinated crops.
    b.    Single crosses, double crosses and synthesized varieties.
    c.    Varietal crosses.

———————— is a thornless and seedless selection from Kagzi lime.

A. Pramalini            B. Vikram

C. Chakradhar        D. Jai devi

1. Quantitative characters are governed by

a) Monogene

c) Recessive gene

b) Bi-gene

 d) Polygene

2. Monohybrids are derived by hybridizing two individuals which differ for

a) Single-character

c) Quadruple character

b) Double character

 d) Multiple character