eChapters

Introduction

Plant genetic resources management essentially consists of two phases; its conservation and utilization. Germplasm conservation includes acquisition, in which germplasm is safeguarded in situ (by establishing reserves) or ex situ (by assembling collections through exchange or exploration). It also involves maintenance, protecting germplasm in situ in reserves or storing it ex situ under controlled conditions, propagating it while preserving its original genetic profile with maximum fidelity, monitoring its viability and health in storage or in situ and maintaining associated passport information and other data. Germplasm conservation also involves characterization, assessing highly heritable morphological and molecular traits for taxonomic, genetic, quality assurance and other management purposes. The second phase of germplasm management, encouraging utilization, includes evaluation, assessing agronomically or horticulturally important traits with relatively low heritability and high components of environmental variance e.g. yield adaptation and host-plant resistance to certain abiotic/biotic stress. It also includes genetic enhancement, making particular genes more accessible and usable to breeders by adopting exotic germplasm to local environments without losing its essential exotic genetic profile and/or introgressing high value traits from exotic germplasm into adapted varieties. Genetic enhancement can be subdivided into introgression i.e. backcrossing a few genes controlling desired characters into adapted stocks and incorporation i.e. the large scale development of locally adapted populations good enough to enter the adapted genetic bases of the crops concerned.

Molecular markers may be a short DNA sequence that flanks base pairs like SNP, a Single Nucleotude Polymorphism, small fragment or SSR Single Sequence Repeat or an extended site as in the case of microsatellites. Schematic representation of the SSR assay is shown in Fig. 1. Genetic markers have to be easily identified, linked to a specific locus and polymorphic. Molecular markers are subdivided into codominant monolocus and polyallelic markers and the second group contains dominant, polyallelic and biallelic markers. 

ABSTRACT

Genetic improvement of crop plants through conventional plant breeding has made tremendous contributions to the breakthrough in the global agricultural production. Recently, an array tools and techniques in the field of molecular biology has become available for supplementing the conventional genetic approaches. Consequently, new integrated approaches are being designed. One of the approaches employs molecular markers for genome mapping, gene tagging and marker assisted selection (MAS). With the complete sequencing of whole plant-genomes and a large number of random cDNAs in many different crop species, newer opportunities are emerging. This presentation is an attempt to briefly describe the current applications of molecular markers and to highlight their future prospects.

Molecular markers

Molecular markers are heritable differences in nucleotide sequences of DNA at corresponding position on homologous chromosomes of two different individuals, which follow a simple Mendelian pattern of inheritance. These differences are detected employing two basic techniques: (a) Southern blot hybridization and (b) Polymerase chain reaction (PCR). Restriction Fragment Length Polymorphism (RFLP) is the first molecular marker system to be conceived and developed. It is based on the southern blot technique. Markers such as random amplified polymorphic DNA (RAPD), sequence tagged site (STS) and amplified fragment length polymorphism (AFLP) are generated by enzymatic amplification of DNA by extension of oligo nucleotide primers and therefore, are based on PCR. Single/simple nucleotide polymorphism (SNP) markers are based on DNA sequence differences as revealed by sequencing and assayed by various techniques.

The harmony between human beings and plants is one of the evergreen reasons that maintains and supports life on earth. This fact clearly explains why any hazard to the life of plants prominently affects man. One important feature distinguishing plants from other complex multicellular organisms is that plants are sessile and thus have to endure environmental challenges (Zhu, 2001).

Crop productivity is limited by stress factors. The stresses which pose major threats to survival of plants belong to two categories- abiotic and biotic stress. Drought, salinity, high or low temperatures, light, deficient or excess nutrients, heavy metals, pollutants etc., either individually or in combination causes abiotic stresses. Biotic stress refers to any stress provided by living organisms, be it unicellular or multicellular. Plants facing a variety of biotic and abiotic stresses are able to protect themselves by means of tolerance mechanisms which result from changes at the molecular level. They are often confronted by a multitude of stresses in their natural environment. To overcome this, plants have evolved various defence strategies, which involve comprehensive reprogramming of the cellular metabolism.

Use of morphological markers has continued till today for characterization of several crops including horticultural crops with the Mendel’s principles of inheritance by following visible traits in the progenies of sexual crosses. Genetic markers play an essential role  in the study of variability and diversity, in the construction of linkage maps, and in the diagnosis of individuals or lines carrying certain linked genes. Within this context, the limitations of morphological markers became quickly apparent. They tend to be restricted to relatively a few traits, display a low degree of polymorphism, are often environmentally variable in their manifestation, and can depend on the expression of several unlinked genes. Furthermore, some may affect plant viability or seed set, distorting gene frequencies in the progeny. Morphological markers were largely supplemented by biochemical markers, particularly isoenzymes that could be easily scored by electrophoresis (Ganapathy and Scandalios 1973; Tanksley 1983). The limitations of isoenzmyes as markers, in particular both the limited number of polymorphic enzymes that can be conveniently stained and the environmental effects on expression pattern, were apparent already twenty years ago (Tanksley 1983).

Vegetables have always been looked upon as an essential part of diet and are necessary for human health and well-being. Vegetables supply many kinds of nutrients, e.g., carbohydrates, proteins, minerals, vitamins, fibers, phytochemicals, etc. and also add flavour, colour and crispness to foodstuffs. For developing modern day vegetables, breeders have utilized an understanding of genetic principles and applied them for the improvement of these crops. They often make crosses (hybridization) between a crop plant and a related or wild species (a wide cross) enabling valuable genes to be used for genetic improvement of the crops. Over the last few decades, molecular breeding is supplementing plant breeder’s efforts for accelerated genetic enhancement bringing about a revolution in this area. This approach demands efficient procedures for the routine introduction of foreign DNA into plant genomes and utilizing them for the production of novel types of vegetable. In this chapter, attempts have been made to review most of the available molecular breeding techniques, which can routinely be employed in various aspects of vegetable improvement.

Cultivars are developed by selecting for desired traits or by removing undesirable traits that are controlled by genes (the blueprint for all characteristics in living organisms) from existing varieties or breeding lines. The plant species, varieties and clones are identified or selected by their physical features since olden times. However, these traits would change with respect to environmental and climatic conditions. The biochemical parameters like enzymes, proteins, alkaloids, etc. are also likely to change due to the stages of development of plant tissue. Successful selection strategies are dependent on the breeder’s ability to distinguish genetic effects from environmental effects on a visible or measurable trait. Therefore, the scientists resorted to use ‘genetic marker’, i.e., any stable and inheritable variation that can be measured or detected by a suitable method and can be used subsequently to detect the presence of a specific genotype or phenotype, which otherwise is very difficult to detect. Presently, the breeders and scientists all over the world are pursuing mostly DNA or molecular markers.

Monitoring the microclimate inside protected cultivation systems—such as greenhouses, polyhouses, net houses, and other semi-controlled environments— plays a crucial role in modern agricultural practices that aim to enhance crop productivity, quality, and resource efficiency. As global demand for high-quality and high-yield crops continues to rise, protected agriculture has become a key solution for mitigating the effects of climate variability, pest infestations, and limited available land. However, the effectiveness of these systems largely depends on the ability to continuously monitor and regulate the essential microclimatic factors that directly influence plant health, disease resistance, and overall productivity. Microclimate refers to the localized climate conditions within a specific area— in this case, within the protected structure—that can differ significantly from external environmental conditions. Key parameters typically monitored include temperature, relative humidity, solar radiation or light intensity, carbon dioxide (CO?) concentration, vapor pressure deficit (VPD), and air movement or circulation. These factors are interrelated, and even minor fluctuations can greatly impact plant health, photosynthesis, transpiration, and reproduction. Thus, accurate and continuous monitoring of these variables is essential for effective climate control and optimal crop growth.
Temperature is arguably the most critical variable, as it controls metabolic processes, enzyme function, flowering time, and fruit development. A deviation from the ideal temperature range can either accelerate or stunt plant growth, leading to reduced yields or even crop failure. In tropical or semi-arid climates, temperature spikes inside protected structures can result in heat stress, while in temperate or mountainous regions, low temperatures can hinder growth. To mitigate this, temperature sensors—such as thermistors, RTDs, or thermocouples— are placed at different heights and zones within the structure to ensure uniform monitoring. These sensors typically transmit real-time data to centralized systems that control heating, cooling, and ventilation systems. Along with temperature,

Botany

The plant is highly cross pollinated due to heteromorphism and bees being the major pollinators.

Varieties: PKM 1 & PKM 2

Method of seed production : Seed to Seed.

Land requirement : Uproot all the wild and non specific moringa trees if any near the field within a radius of 1500ft. Good drainage facility is must for moringa.

Isolation requirement : A distance of at least 500 M is necessary for seed production.

Season : Early season (July August), Mid season (September), Late season (October -November). Best season is September October, so that flowering starts during summer which facilities better pollination and seed set.

Most of the DNA of an living organism is packaged and organized in a chromosome as well as in mitochondria and cell organelles (Feulgen and Rossenbeck 1924). DNA is not found on its own but rather is structured in long strands wrapped around protein complex called nucleosome consisted of a protein called histone. During most of the duration of cell cycle a chromosome consists of long double helix DNA molecule (with associated proteins)During S phase the chromosome gets replicated resulting in X –shaped structure (chromatids) and still attached to a single centromere. The basic role of the chromosome is to provide a frame work which allows each linear segment of the genome to replicate and segregate efficiently. Failure in either of processes cause chromosome imbalance in daughter cells. Three specific cis-acting sites are required for stable chromosome maintenance, i.e., an origin of replication, a centromere and telomeres.

Classical studies of the morphologyof individual chromosomesof the plant species begun by S. Nawaschin 1910-16 and continued by Taylor (1925), Sharp (1929) and Mc Clintock (1929-30). And eventually it was possible to set up working models which account for the internal structure and chemistry of the chromosome and the genetic material as well as genetical facts. The use of aceto-carmine with iron (Belling, 1921) and application of heat greatly improved the staining differentiation of chromosomes. Smears have practically replaced the paraffin techniques of studying chromosome. The gross morphology of chromosomes is generally worked out either at prophase stages of meiosis or metaphase in somatic tissues. The chromosomes may differ in thickness, total length, position of centromere or spindle fiber attachment region, chromomere pattern and number and position of secondary constriction. The total length of chromosomes at metaphase also differs in different tissues of a species and also in certain tissues chromosome present may be very different in appearance. Figure 1 shows various morphological features of a eukaryotic chromosome

Purpose: In propagation of fruit plants by any vegetative methods such as cuttings, budding and in to the selection of ‘mother plants” and “bud-wood”. Use of bud-wood or any other propagation material from high yielding, true to-type, disease free trees (mother plant) will ensure uniform behaviour of trees in the orchard. If possible, propagation material from a single source is used.

Bud-wood used for budding purpose from high yielding, true-to-type and disease free trees certified for the above character by a certifying agency is referred as ‘certified bud’

Procedure: By adopting the flow sheet given below, clean scion from healthy, productive plants, can be selected for vegetative propagation.

Mulching is a practice of covering the surface of soil with plastics, organic and non-organic materials like straw, grasses, sands, stones (boulders), synthetic plastics, etc. to reduce evaporation and to moderate wide fluctuations in diurnal soil temperature, especially in the root zone environment. It controls external evaporability and reduces energy supply to the evaporating site by cutting off solar radiation falling on the ground. Its main function is limited to control first stage of drying, which helps in improving moisture status and reducing soil temperature (Loy and Wells, 1975), besides checking seedling mortality and improving crop stand. It also suppresses weed-flora and reduces weed competition with crop for water and nutrients making them available in greater quantities for crop plants. Moreover, mulching helps in increasing downward movement of water, and its storage deep in the profiles escapes evaporation due to reduction in thermal gradients and exchange of vapours. The effectiveness of mulches in conserving moisture has generally been found to be higher under more frequency of rainfall, drought conditions and also during early period of plant growth when canopy cover remains scanty.

Abstract

Three mulch materials (black polyethylene, white polyethylene, and paddy straw) were evaluated to reduce albinism  in five cultivars of strawberry.  The incidence of albinism was the highest (38.60%), with black polyethylene and the lowest with paddy straw (22.45%). Among cultivars, Etna had the highest incidence of albinism (50.60%), followed by Chandler (41.60%), where as  Sweet Charlie had the least (22.50%).

Mulching

It means covering of soil surface by some organic or inorganic materials for conserving the soil moisture besides covering on the soil moisture several other advantage of mulching. The materials which are used in mulching called mulch.

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.

16.1 INTRODUCTION

Mulch, a technical term, means ‘covering of soil’. A mulch is a layer of material applied to the surface of soil. It may be applied to bare soil or around existing plants. Mulches of manure or compost will be incorporated naturally into the soil by the activity of worms and other organisms. Mulching is the process or practice of covering the soil/ground to make more favourable conditions for plant growth, development and efficient crop production. While natural mulches such as leaf, straw, dead leaves and compost have been used for centuries, during the last 60 years the advent of synthetic materials has altered the methods and benefits of mulching. The research as well as field data available on effect of synthetic mulches make a vast volume of useful literature. In this manner it plays a positive role in water conservation. The suppression of evaporation also has a supplementary effect; it prevents the rise of water containing salt, which is important in countries with high salt content water resources.

Genotype × environment interaction underlies the efforts of crop ecologists, agronomists, and plant breeders to define ecological regions, mega-environments, and ecotypes and to specify the adaptation and yield stability of individual cultivars. Multi-location testing or multiple year testing gives rise to an important term, genotype x environment interaction. “Interaction” is a statistical term signifying differential response of genotypes over the environments. The environments could be in terms of more numbers of diverse locations or years. Multi-location trials (MLTs) are also called as multiple environment trials (METs) and these have been adequately reviewed by Yan and Hunt (1998) and Kang et al. (2004). The following sections of this chapter derive extensive information on MLT/MET from these two sources.

Introduction

The genotype-environment-interaction (GEI) is a complex phenomenon that undermines the repeatability of experimental results and consequently reduces the selection efficiency. Agricultural researchers have long been concerned of the various implications of GEI in plant breeding programmes. Understanding of the implications of GEI structure/nature is important in crop breeding programmes as a significant GEI can seriously impair selection of superior genotypes in new crop introduction and cultivar/hybrid development programmes. Crop breeders of field and vegetable crops, etc. are in better position to decide whether crop cultivars should be developed for all the environments of interest or if the breeders should develop specific cultivars for specific target/mega environments. Variation among genotypes in phenotypic sensitivity to the environment may require the development of locally adapted varieties.

Genotype-by-environment is widely observed and reported issue. Large numbers of publications both on GEI and stability parameters are pointers to the facts that it is a complex and intriguing issue and these are expected to be more relevant in the light of the fact that greater emphasis is going to be placed on sustainability of agricultural systems.

1. Introduction

A combination of art and science had been used for a longer but due to the exponential increase in human population and reduction in operational land holdings its practices became narrow. Nowadays, gardening has gained much popularity among people, as the Covid-19 pandemic has forced them to lock themselves in their houses. These days Mass population is involved in gardening for growing their own food, resulting in a more personal approach to more economical, better-tasting, and healthier products (Pawelek et al., 2009). Gardens have grown increasingly significant for producing nutrient-dense food, protecting biodiversity, and conducting biological and ecological research and education. Biological communities, which are interacting groups of numerous species in the same place, can also be found in gardens. Pollinators and other visitors to flowers eat nectar and pollen from flowers, and some may use floral volatile oils, lipids, or resins for their food, shelter, and mating locations (Simpson and Neff, 1983).

ABSTRACT

Multiple shoot induction from the cotyledonary node explants of Leucaena leucocephala was studied in presence of various concentrations of TDZ. With the increase in concentration of TDZ from 0.045 μM to 0.227 μM the number of regenerated shoots increased. However, the length of individual shoot decreased. Further increase in TDZ concentration upto 22.71 μM resulted in the formation shoot clusters. Presence of TDZ in the medium inhibited shoot elongation. Transfer of the regenerated shoots to ½ x MS medium supplemented with 0.54 μM NAA ensured elongation of the shoots, which also developed roots. Rooted plantlets were transferred to coco peat for further development and hardening. This highly efficient regeneration protocol may find application in the genetic transformation of this leguminous tree species.

1. INTRODUCTION

Mushrooms are edible fungi of commercial importance and their cultivation has emerged as a promising agro-based land-independent enterprise. There are about 20 varieties of mushrooms being cultivated throughout the world for food. In India, only white button mushroom (Agaricus bisporus J.E. Lange Imbach), oyster mushroom (Pleurotus spp. [Fr.] P. Kumm) and paddy straw mushroom (Volvariella volvacea [Bul.] Singer) are grown commercially. Of these, white button mushroom contributes ~90% of the total production. Mushrooms have been recognized as an alternate source of good quality protein and produce the highest quantity of protein per unit area from agro-wastes. Besides, they provide potentiality for generating employment, improving economic status of growers, help in checking pollution and earn foreign exchange.

Out of the total production about 45% of mushrooms produced are consumed in the fresh form while the other 55% are processed, with 5% in dehydrated form and 50% in canned form. This is because their shelf-life in the fresh form is very short and hence mushrooms are traded in the world market mostly in the processed form. Fruiting bodies (reproductive phase) of Agaricus are appreciated not only for texture and flavour but also for their chemical and nutritional characteristics.