eChapters

11.1 Introduction

In chapter 10, we have discussed the different types of variation, namely, genetic, environmental and genotype × environment interaction variations. We have also learnt how to estimate the phenotypic variance and its components including genotypic (also called genetic), environmental and g × e interaction variances from trial data. Now in this chapter, we shall discuss on the genetic components of polygenic (quantitative) variation and its implications on breeding strategies.

11.2 Genetic Components of Polygenic Variation

In this chapter whenever we call genetic variation, we mean polygenic (quantitative) variation, and we know that variation is usually measured in term of variance. However, variation, variability and variance are almost used synonymously. The genetic variance has been classified into different components by various workers. Fisher (1918) divided genetic variance into three components: additive, dominance and epistatic (interaction) variances. Wright (1935) classified genetic variance into two components: additive variance and non-additive variance (dominance and epistatic variances). Mather (1949) classified genetic variance into two components: heritable fixable variance (additive variance and additive × additive epistatic variance) and heritable non-fixable variance (dominance variance, and additive × dominance and dominance × dominance epistatic variances). Later, Hayman and Mather further divided the epistatic variance into three categories: additive × additive, additive × dominance and dominance × dominance.

ABSTRACT

India is the largest producer of banana, contributing to 17.3 per cent of the global production. In Kerala, it is the leading fruit crop, being cultivated in an area of 99,412 ha with an annual production of 7,31,650 tonnes. Biodiversity in the cultivars of banana, which consist of triploids, is complex especially in Nendran. Nendran belonging to Musa AAB plantain subgroup is the leading banana cultivar of the Kerala. in Kerala, several landraces are available, cultivated in different parts, known in different local names. Twelve Nendran ecotypes of banana belonging to AAB genomic group were collected from Banana Research Station, Kannara, Banana Nursery Farm, Palode and Instructional Farm, College of Agriculture, Vellayani to ana lyse genetic divergence using RAPD marker and morphological traits. Out of the forty one decamer primers screened for RAPD analysis, 34 could produce amplification. Twenty five primers showed high level of polymorphism. Finally, six of the most promising primers viz., OPA-01, OPA-03, OPA-13, OPB-04, OPB-10 and OPB-12 were used for RAPD analysis. Statistical analysis for the morphological traits and RAPD marker were conducted using the software programme NTSYS pc version 2.02e. The matrix average taxonomical distances (similarity coefficient) among the ecotypes ranged from 0.59 to 1.00 in RAPD profiles and morphological profiles (dissimilarity coefficient) ranged from 2.82 to 11.21. In the dendrogram (RAPD profiles), Koonoor Ethan showed the maximum genetic divergence. Quintal banana and Zanzibar came under a single clusters at a distance of 0.79 and clustered together at a distance of 0.82. Both the ecotypes showed next higher genetic divergence among the Nendran ecotypes. In the case of morphological traits, the same trend could be observed. Koonoor Ethan showed the maximum genetic divergence at a distance of 11.21 and Quintal banana showed next higher genetic divergence at a distance of 9.11. Koonoor Ethan, Quintal banana and Zanzibar were distinct ecotypes among the Nendran ecotypes of Kerala

ABSTRACT

The investigation aimed at to examine the diversity among nineteen wild and cultivated germplasms of the genus Vigna namely, V. trichuriensis, V. hainiana, V. radiata, V. aconitifolia, V. minima, V. sinensis, V. radiata var. sublobata, V. radiata var.setulosa, V. umbellata, and allopolyploid of BR3x T9 at DNA level follwing Random Amplified Polymorphic DNA (RAPD) technique. Ten random decamer primers were used in amplification reactions, five of that were reproducible and clear. The five primers constituted 55 bands of, which 9 are polymorphic. The similarity index based on 0 and 1 matrix of banding was calculated and dendrogram following UPGMA was constructed. The germplasms formed altogether 4 clusters on the basis of 0.375 linkage distance. The first and second cluster consisted of single genotype of V. hainiana. and V. minima respectively. The third cluster comprised wild and cultivated types of V. sinensis. The 4th cluster on the otherhand, consisted of genotypes belonging to V. radiata, V. radiata var. sublobata, V. mungo, V. radiata var. setulosa, V. trichuriensis and allopolyploid of BR3 and T9. The wild forms of different species were found to exist in the same cluster as their cultivated form. The three mungbean genotypes namely B105 (V. radiata), B1 (V. radiata) and BR3 (V. radiata )are crossable within themselves and they belonged to the cluster -IV.The intercluster cross between different clusters would like to generate new genotypes with wide variability. Based on limited range of accessions tasted in the present investigation, the approach holds promise for the classification of Vigna germplasm, identification of Vigna and marker assisted breeding in Vigna.

Vegetables are of short duration, have higher productivity and give more return per unit area, besides giving nutritious food to human being and can be fitted in different farming systems. They also play a major role in balancing human diet, thereby helping in alleviating hunger, poverty and malnutrition. Because of the public awareness for the significance of vegetable consumption, the demand of vegetables in the global market has increased immensely. Thus, vegetable farming is becoming profitable venture globally, opening avenues of self employment and revenue generation (Anon., 2009). At global level, India holds second position, next only to China in vegetables production with a share of about 14%. The present annual vegetables production of country is about 175 million tons from an area about 10.3 million ha with a productivity of 17.1 t/ha. India grows largest number of vegetables in the world, as having a spectrum of wide range of agro-climatic situations, ranging from dry temperate to humid tropics between the altitudes from sea level to snow line.

The Indian hot arid region is one of the most important arid ecosystems of the world in terms of biodiversity it possesses. This arid region spreads over 31.7 mha, occupies major part of north western India including Rajasthan, Gujarat, Punjab and Haryana, which together contribute 73% of arid region. High temperature, wind velocity, low humidity, low and erratic rainfall and high potential evapotranspiration are important characteristics of this region which narrowed down the choice for vegetables, besides permit their low productivity.

ABSTRACT

Of the several PCR techniques developed during the last two decades, random amplified polymorphic DNA (RAPD) offers a simple and economical means of genotype characterization. The information obtained through RAPD characterization is extensively used for the identification of genotypes, screening of duplicates, assessing genetic diversity and monitoring the genetic stability of conserved germplasm. The present study is a report on the DNA fingerprinting of P. nigrum and P. longum cultivars. Fourteen land races and three advanced cultivars of P. nigrum and eleven land races and one advanced cultivar of P.longum were used in the present study. Forty decamer primers from Operon Tech were screened using two representative genomic DNA samples of black pepper. Of these, 10 primers that yielded clear and dominant band patterns were selected for the final analysis of the 29 accessions. These generated 119 amplification products. The total number of markers per primer varied with respect to both P. nigrum and P. longum. Cultivar specific single bands were obtained for a few land races and accessions of both the Piper species.

ABSTRACT

Plant tissue culture is an important and efficient technique for the production of desired plant products with different and improved variety in aseptic conditions. Plant tissue culture methods have a wide scope for the creation, conservation, and utilization of genetic variability for the genetic improvement of field, fruit, vegetable, forest crops, medicinal and aromatic plants. The main objective of this communication were to collects the information and techniques of tissue culture to genetic improvement of the medicinal plants. Tissue culture technique in combination with molecular techniques has been successively used to incorporate specific traits through gene transfer. Modified varieties of medicinal plants is mostly required, as some compounds like alkaloids, terpenoids, steroids, saponins, phenolics, flavanoids, and amino acids etc are extracted from these plants. From the ancient time up to 20th century, most of the human-being are dependent on the medicinal plant for basic healthcare needs and improving such a crop is the most important for this billionaire world. As far conventional methods of genetic improvements the tissue culture techniques takes cheap and lesser time required for traits specific improvements in the MAPs.

The Cucurbitaceae family is characterized by long training viny stems. There is variation for flower size and colour among the species but all of them have similar general morphology. The species are open pollinated and self compatible. Most of them are either monoecious (eg. Cucurbita spp.) Or andromonoecious (e.g. common in melon). Other species show gynomonoecy, androgynomonoecy, androecy, gynoecy, hermaphrodite or dioecy. Chow-chow is the only member of the Cucurbitaceae that is viviparous, contains single seed and propagated by planting whole fruit. The Indian gene centre has rich diversity in genetic resources of ridgegourd (Luffa acutangula), bottlegourd (Lagenaria siceraria), bittergourd (Momordica charantia), ashgourd (Benincasa hispida), snakegourd (Trichosanthes anguina), pointed gourd- parval (Trichosanthes dioica), pumpkin (Cucurbita spp.) and roundgourd (Praecitrullus vulgaris). Cucurbits are of tremendous economic importance and are cultivated throughout the world from tropical to sub-temperate zones. China, Turkey, India and Iran are important cucurbit growing countries. In India, this diversity is concentrated in Indo-Gangatic plains, north eastern region, north western Himalayas, the Western and Eastern Ghats and sporadically in the tribal dominant belts of central India.  More diversity occurs in Cucurbita spp. in the north east as also for ashgourd, bottlegourd while for Luffa, it is more concentrated in the eastern peninsular tract.

Tripura is situated between 22º 56’to 240 32’ N latitude and 91010’ to 92021’E longitude with tropic of cancer passing through it. The total geographical area of state is about 10,491 km2 of which 57.98 % area is under forest cover.  Agriculture is an important sector in the state, which contributes 26 % of the State GDP of which the major contribution is from horticultural crops like fruits (pineapple, litchi and oranges), vegetables (potato TPS), plantation crops (cashew nut, coconut, rubber and tea) and spices (ginger, turmeric and black pepper). More than 75 % of the population either directly or indirectly depends on agriculture. The small and marginal farmers constitute about 90 % of total farming community and the average size of land holding is 0.97 ha (1990-91) in comparison to 1.25 ha (1976-77), which is the lowest among the seven other North Eastern states.

With the advent of clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein9 (CRISPR/Cas9) genome editing, a fast and efficient new breeding technology, precision breeding in vegetable crops has become possible now. Several genes have been edited and functionally characterized using CRISPR/Cas9 in tomato for multiple traits such as plant type, floral morphology, fruit traits, disease resistance, and abiotic stress tolerance. The CRISPR/Cas9 has been proven in successful introgression of de novo domestication of elite traits from wild relatives to cultivated tomato. The progress in CRISPR/Cas9 based improvement in vegetable improvement, has been discussed.
Vegetables are an important source of healthy diet, as they provide essential nutrients including vitamins, minerals, dietary fibre, antioxidants and other phytochemicals. Dietary fiber-rich vegetables improve digestion, while also lowering the risk of obesity, diabetes, high cholesterol and heart disease (Behera et al., 2021). A world vegetable survey showed that around 392 vegetable crops are cultivated worldwide, representing 70 families and 225 genera. Over 97 species of higher plants are being cultivated and consumed as vegetables in India. These crops belong to 20 different families such as Cucurbitaceae (25 crops), Fabaceae (16 crops), Brassicaceae (12 crop) and Solanaceae (6 crops). The world’s total vegetables production was 1,155 million tonnes in 2021 where China ranks first with a total production of 600 million tonnes, accounting for 52.18% of the total world production. The top 5 countries (China, India, the United States of America, Turkey and Vietnam) account for 70.36% of total world’s production. As far as India is concerned,  it is the largest producer of ginger (2.23 million tonnes) and okra (6.47 million tonnes) in the world, while ranking 2nd in potato (54.23 million tonnes), dry onion (26.64 million tonnes), cauliflower and broccoli (9.25 million tonnes), brinjal (12.87 million tonnes) and cabbage (9.56 million tonnes) (FAO 2023).

1. Introduction

Fenugreek (Trigonella sp.) is one among the world’s oldest seed spice crops and has gained a supreme importance due to its extensive pharmacological properties (Basu and Prasad, 2011; Maloo et al., 2020). In ancient time’s fenugreek plant was well known and used as a medicinal drug by Egyptians (Rouk and Mangesha 1963). The Ebers Papyrus (one of the oldest preserved pharmaceutical documents) detailed therapeutic advantages and descriptions in Egypt circa 1500 BC (Betty, 2008). It has gained great importance due to its multifaceted uses which are being exploited by farmer’s and industrialist for different purposes.

In this era of molecular markers in genetic studies, genome analysis encompasses several stages of increasing resolution and sophistication, leading to the generation of high resolution chromosome maps. Since the entire plant kingdom cannot be covered under sequencing projects, molecular markers and their correlation to phenotypes provide us with requisite landmarks for elucidation of genetic variation.

A molecular marker is a site of heterozygosity for some type of DNA variation. Such a DNA marker in mapping analysis is analogous to a conventional heterozygous allelic pair. When they are used for mapping the genome, the identity of this DNA fragment is not important, but is simply used as a reference point to arrange and order the genetic information along the length of a chromosome. The molecular markers provide landmarks along the length of chromosome that facilitate the manipulation of chromosome segments in breeding and chromosome engineering programs.

Fruits contribute to nutritional security and thus are an important part of food system. To meet the future demand, development of varieties with improved yield and quality is the focus of researchers involved in fruit breeding. Though conventional breeding has resulted in the development of improved commercial varieties of different fruit crops, however conventional breeding is time consuming and faces several challenges due to long juvenile phase, highly heterozygous nature of most of the fruit crops. Challenges like changing climate, consumer preference, socio-economic conditions like reduced availability of land, labour and increasing cost of inputs, require fast and efficient methods to develop the varieties to meet the demands, which is not feasible with conventional breeding. Marker assisted breeding has given impetus to breeding efforts in several fruit crops, however it’s use is limited only for the traits controlled by a few major QTLs.
During last few years, enormous genomic resources have been developed for fruit crops using next generation sequencing technology. Such advances in genomic research in many fruit crops have paved the way for precision breeding using genomic assisted breeding (GAB) tools. GAB has helped in characterisation and utilisation of genome resources and using allele variation for cultivar development (Varshney et al. 2021). Advances in sequencing technology and affordability has allowed the genome wide analysis (GWAS) on diversity panels of different fruits resulting in identification of allelic variation associated with the traits of interest. Also, identification of superior alleles of candidate genes makes them amenable to genome editing based precision breeding. Genome wide genotyping and phenotyping offers tools for developing strategy for genomic selection (GS). Genomic selection relies on the prediction of breeding values of tested genotypes based on the large number of markers spread over entire genome. These tools promise to further improve breeding efficiency in fruit crops.

Safety is a prime concern for humans and animals. Without evaluating the safety of a chemical, no regulatory authority in the world allows the chemical to be used by humans. There are stipulated guidelines for toxicity evaluations. Among the toxicity assays genotoxicity assays are important and have occupied centre stage due to increase in understanding of the genome.

Genotoxicity describes the property of chemical agents to damage the genetic information within a cell to cause mutations, which may even lead to cancer. While genotoxicity is often confused with mutagenicity, all mutagens are genotoxic; however, not all genotoxic substances are mutagenic. Generally and depending on the agent, a cytotoxic agent may be genotoxic (causing DNA damage), mutagenic (causing gene mutation) or it may be harmful for cell organelles (e.g. cell membrane) or it may even be teratogenic. Therefore, every cytotoxic agent is not genotoxic.

Why we Need to Evaluate Genotoxicity?

Toxicity can be at any level according to the nature of chemicals and type of exposure. Duration of toxicity can also be short lived or long lived within a generation or continue to next generation. Genotoxicity effects are able to continue in next generation(s), in which the exposed population may not suffer seriously but the next generation may suffer without being exposed to the same chemicals. Therefore, genotoxicity evaluations need serious attention.

Abstract

Genus Artemisia L. (Asteraceae) has a long history of use in herbal medicine, owing to the presence of rich bioactive phytochemical diversity of it constituent species. Himalaya is hub of several species and species under this genus have been traditionally used in different ways for curing ailments by inhabitants of the areas where their populations sprawl. Few species such as A. annua and A. maritima are cultivated for their use in medicine. In addition, the species of the genus have found wide usage in matters connected to digestive system especially for treatment of worms and for preparation of herbal teas. Artemisnin, a potent source of anti-malarial drug extracted from some species, is most valuable bioactive phytochemical of this genus. Other important chemical constituents include santonin and scoparine. Reported studies suggest that the bioactive constituents present in this genus shows several biological activities such as antimicrobial, anti-inflammatory, anticancerous and other allied ones activities. Expansion of range and acclimatization in new habitats is exemplary in this genus. Present work reports the ways of range expansion, economic importance, conservation strategies and future prospects of this genus.

World Trade Organisation

The World Trade Organisation (WTO) was the result of years of painstaking efforts on the part of governments and other bodies to establish a globally acceptable basis for a new economic order. It was established to correct the imbalances and disparities in international trade and bring about an evenly balanced world trade order that equally benefits the developed, developing and least developed nations. While there are several agreements under the WTO, the Agreement on Trade Related Aspects of Intellectual Property Rights (TRIPS Agreement) specifically represents the resolve of all member countries to use intellectual property as one of the means for achieving economic balance and diminishing the trade barriers.

The term Geographical Indications (GIs) attained significant status in trade agreement negotiations after the establishment of World Trade Organization (WTO).Under WTO, Agreement on the Trade Related aspects of Intellectual Property Rights (TRIPs) sets forth standards to regulate international intellectual property protection and enforcement and establishes international minimum standards for GIs. Geographical Indications identify goods that have a specific geographical origin and possess a quality, reputation or other characteristics which are due to that place of origin. Geographical Indications are now widely accepted as valuable marketing tools in the global economy and are useful to protect rights of communities. Geographical Indications are not granted to individuals but are granted to the group/association of producers as the symbol of collective ownership.

Introduction
Geranium is also known as cranesbill, scented geranium/rose geranium. It is adaptable over a wide range of soil conditions and drought tolerant. Being perennial aromatic herb, it is cultivated for rose scented essential oil extracted from leaves and tender shoots. The oil thus obtained is also called pelargonium oil or rose-geranium oil. The oil is of varied colour from colourless to pale yellowbrown or greenish. The genus Pelargonium belongs to the family Geraniaceae.
Origin
Geranium is native to sub-tropical southern Africa, and the most popular of bedding and green-house plants. The genus Pelargonium consists of about 600 species, which are annual, biennial, and perennials found in Cape province of South Africa.
Botany
The cultivated geraniums may belong to herbaceous to woody with thick fleshy leaves of round to lobed shape and deep cut. The flowers are present in terminal clusters with varying colours from white to pink, deep red and violet. Cultivated species are hybrids, having double flowers of mixed colours.

.1. Origin and distribution

• Native of the Cape Province in South Africa.

• Grown in India, South Africa, Belgium, China, Congo, Egypt, France, Madagascar, Morocco, Reunion Islands, Spain, former USSR countries.

• Commercially cultivated mainly in Nilgiris and Kodaikanal hills of Tamil Nadu, and in and around Bangalore in Karnataka.

5.2. Economic importance

• Very profound and strong rose like odour.

• Also known as rose geranium.

• Chief constituent of oil - geraniol and citronellol.

Scientific name: Pelargonium graveolens L. Herit
Family: Geraniaceae
Geranium, scientifically known as Pelargonium graveolens L. Herit, belongs to the Geraniaceae family. This aromatic plant is highly valued for its essential oil, which boasts an intense rose-like fragrance. Geraniol and citronellol are the primary constituents of this oil. There are approximately 600 species within the genus Pelargonium, many of which possess a pleasant odor, although only a few have attained commercial significance.
Types of Geranium
There are two primary types of geranium: Algerian or Tunisian Type: Characterized by slender, erect plants with dark pink flowers. This variety contains 0.3% oil, with 57% 1-citronellol. It is commonly grown in the Nilgiris and is unsuitable for wet conditions. Reunion or Bourbon Type: Produces more bushy growth with light-pink flowers. The oil has a higher 1-citronellol content (59.4%). This variety is grown in the Nilgiris and Anamalais and is more suitable for wet conditions.

Plant genetic resources are the key components of crop improvement because of development of precision breeding system through biotechnological approaches as well as conventional system of breeding like selection and hybridization. Breeding system of hybridization is replaced by cybrid technology that facilitates transferring more qualitative and quantitative traits rapidly within incompatible genotypes. Aonla is mainly recognized for its high nutritive, medicinal and therapeutic properties. It contains high amount of vitamin-C (500-1500mg/100g), it is also rich in pectin, iron, calcium and phosphorus. Dried fruits of aonla can be used in curing haemorrhage, diarrhea, chronic dysentery, diabetes, jaundice, dyspepsia and cough. Recently, aonla gained more popularity in arid and semi- arid region of the country because of its hardy nature, prolific bearing capacity and ability to grow under various adversities as a remunerative crop (Shukla et al.2002). Aonla is the main ingredient of Chavanprash and Triphala powder, used for curing different   human ailments. Fruit contains a chemical substance gallic acid and leucoanthocyanin, having antioxidant property.