Preface The Fifth Deans’ Committee of Indian Council of Agricultural Research has recently revised the syllabus of B.Sc. (Hons.) Horticulture which is uniform throughout the country. The course ’Plant Propagation and Nursery Management’ is taught in the second semester. The present textbook covers the entire syllabus in 10 chapters. Simple and lucid language has been used for easy understanding of the beginners. The information contained in the book has been gathered from various published sources and internet websites which are mentioned at the end of each chapter under references. Attempts have been made to provide latest information; still some valuable information might have been missed. Questions are set at the end of each chapter to assess the understanding of the students. We have tried our best to remove the errors, typographical or otherwise, from the text; still there might be some. We would highly appreciate if it is brought to our notice for rectification in next edition. We cherish the encouragement and cooperation received from our family members during preparation of the manuscript. We congratulate M/S New India Publishing Agency, New Delhi for their support and publishing in a short time. Though the book is primarily written for B.Sc. (Hons.) Horticulture students, the counterparts of B.Sc. (Hons.) Agriculture also may be benefitted. It may serve as a help book for post-graduate students.

1.1 WHAT IS PLANT PROPAGATION? Propagation of plant is defined as multiplication and perpetuation of new individuals from a selected plant having all the characters of the original one. It is the process of increasing the number of plants of a particular species or cultivar. It refers to the multiplication of an individual plant or group of plants, which have specific value to mankind. New plants or new individuals are required for establishing new plantings/new gardens/new orchards.

2.1 INTRODUCTION Several propagation structures are helpful in propagation of horticultural crops. These structures are helpful for seed germination, rooting of cuttings, layering, grafting etc. and other hardening operations. The structures which facilitate propagation of plants are called propagation structures. Propagation structures are required for propagating plants by seed, cuttings and grafting.2.2 GREENHOUSE Greenhouse is a structure covered with glass or polythene for protection against adverse climatic conditions as well as to provide optimum environment for growth of the plants. Greenhouse has been used long back by horticulturists as a means of forcing rapid growth of plants and extending the growing season particularly in colder areas. Plants are grown or cuttings are rooted in a greenhouse when the atmospheric condition does not permit for raising them in outdoor conditions. Modern greenhouses are equipped with regulatory mechanisms for controlling temperature, light intensity, air, humidity etc. Plants in green house are grown in the ground bed or bench type raised beds. The size of the greenhouses and dimensions of beds vary according to the need of propagators. Glass covered greenhouses are expensive but they have long life. However, for short-term benefits, plastic covered greenhouses can also be made. Plastic covered greenhouses are lighter than glass covered ones but there is increase in humidity is such houses, especially in winters, which results in undesirable water drops on the plants. It can however be overcome by making adequate ventilation. Polyvinyl chloride (PVC) has also been used in construction of greenhouses but it tends to darken pre-maturely in sunlight. In India, construction of temporarily low-cost poly houses is in fashion for raising nursery of fruit plant in off-season. Such low-cost greenhouses are constructed either on wood or metal framework and are covered with polyethylene sheet of 0.10 to 0.15mm thickness, which is resistant to ultra-violet rays. These houses are equipped with thermostat, cooler or an air conditioner or humidifier etc for rigid control on temperature and humidity. Greenhouses made from fibre glass sheet are more durable than the polythene houses, but are quite expensive. In greenhouses, two types of beds are used for raising seedlings. In greenhouses, the beds may either be prepared on ground itself or raised beds or bench type beds are used. Greenhouse structures vary from elementary home constructed to elaborate commercial installations.

3.1 INTRODUCTION A nursery is a place, where seedlings, saplings, trees, shrubs and other plant materials are grown under intensive care and maintained until they are ready for final transplanting in the main field. The importance of the best quality planting material as an initial investment is a well-realized factor for persons engaged in horticulture field. So, nurseries have great demand for the production of plants, bulbs, rhizomes, suckers and grafts. But in general, good quality and assured planting material at reasonable price is not available in most of the cases. Nursery is the basic need of horticulture. Plant propagation techniques and practices is the core of horticulture nurseries. The planting materials for horticultural plantations are raised from seeds and vegetative parts. The difficulty of procuring seeds and their rising cost makes it necessary to find means to increase seedling survival and growth.

4.1 INTRODUCTION The method of propagation in plants may be sexual or asexual. In sexual method of propagation, specialized reproductive cells called gametes are formed by the process of gametogenesis. Fusion of the male and female gametes leads to the development of an embryo and eventually the seed. 4.2 GAMETOGENESIS The production of male and female gametes is known as gametogenesis. It occurs within microspores and megaspores. It involves only mitosis. It is of two types: (1) microgametogenesis and (2) megagametogenesis.

5.1 APOMIXIS Apomixis is derived from two Greek words “Apo” (away from) and “mixis” (the act of mixing or mingling). It refers to the occurrence of an asexual reproductive process in the place of normal sexual processes involving reduction division and fertilization. During sexual reproduction, developmental steps occurring inside the ovule produce the female gametophyte (embryo sac) and following a double fertilization event give rise to embryo and endosperm structures. Apomixis can be best described as the reference to the asexual process. In some species, embryo sac is produced not as a result of meiosis and fertilization but by certain asexual processes. The occurrence of such asexual reproductive process in the place of normal seed reproductive processes of reduction division and fertilization is known as Apomixis. Such seedling plants produced in this manner is known as apomicts. ’’Apomixis’’ is used synonymously with ’’agamospermy’’ (Stebbins 1950), referring to the asexual production of seed. Apomixis (asexual seed formation) is a phenomenon in which a plant bypasses the most fundamental aspects of sexual reproduction—meiosis and fertilization—to form a viable seed. Plants can form seeds without fertilization, and the seed genotype is consistent with the female parent. The development of apomictic technology would be revolutionary for agriculture and for food production as it would reduce costs and breeding times and also avoid many complications typical of sexual reproduction (e.g., incompatibility barriers) and of vegetative propagation (e.g., viral transfer). The application of apomictic reproductive technology has the potential to revolutionize crop breeding. Apomixis is widely distributed among higher plants. More than 300 species belonging to 35 families are apomictic. It is most common in Gramineae, Compositae, Rosaceae and Rutaceae. Among the major cereals maize, wheat and pearl millet have apomictic relatives. Apomixis is reproduction where only one parent passes genes to the offspring (King, 2006). Apomictically produced offspring are genetically identical to the parent (clones).The method is mostly seen in plants, especially flowering plants. Apomixis was defined by Hans Winkler (2008) as the replacement of the normal sexual reproduction by asexual reproduction, without fertilization. Propagation from cuttings or leaves, is not apomixis. Natural replacement of the seed by an asexual method is apomixis.

6.1 INTRODUCTION The ultimate success of an orchard enterprise largely depends upon the quality and genuineness of planting materials as nursery plants are the foundation of the orchard. Fruit crops, mostly being perennial in nature, call for utmost care in selection of cultivar, quality planting material and adoption of right technology for mass multiplication of planting material. Mistakes committed during the initial establishment of orchards cannot be corrected and will cause serious damage to production and productivity. The variation of scion-wood and rootstock has great bearing on the productivity of an orchard. Thus, it is of immense importance having all plants carefully labelled or otherwise marked. Cuttings taken from the mother plant will grow to have the same genetic qualities as the original plant. This is why the plants resulting from these cuttings are called “clones”. When a stem cutting is taken from a mother plant, the piece of stem will produce new roots if it is properly hydrated. Additionally, some plants can be grown from leaf pieces, or leaf cuttings and these will produce both stems and roots. Thus, the progeny trees are the basic component for the multiplication of fruit plants and ultimately deciding the quality and productivity of the fruit crops. Hence, it is necessary to stock the true to type and best quality progeny trees. In asexual methods of plant propagation, plant parts are being used as propagating materials. The plant from which the plant parts are collected is known as mother plant. There is every possibility of transmission of disease or pest which is present in the mother plant to the progeny. The mother plants have to be maintained properly to obtain disease free planting materials so that multiplication of disease/pest can be prevented. Thus, there is a need for the establishment of mother plant block/scion banks.

7.1 INTRODUCTION Grafting and budding are horticultural techniques used to join parts from two or more plants so that they appear to grow as a single plant. In grafting, the upper part (scion) of one plant grows on the root system (rootstock) of another plant. In the budding process, a bud is taken from one plant and grown on another. The practice of grafting can be traced back 4,000 years to ancient China and Mesopotamia. As early as 2,000 years ago, people recognized the incompatibility problems that may occur when grafting olives and other fruiting trees. 7.2 ROOT STOCK The part of the graft that provides root system to the grafted plant is known as rootstock. It is, normally, raised by seeds in the seedbed and then, transplanted in the nursery bed for budding and grafting. Rootstocks are also raised in pots and polythene bags.

8.1 INTRODUCTION Natural methods of vegetative propagation include strategies that the plants have developed for self-multiplication or perpetuation. Natural vegetative propagation is mostly a process found in herbaceous and woody perennial plants, and typically involves structural modifications of the stem, although any horizontal, underground part of a plant (whether stem, leaf, or root) can contribute to vegetative reproduction of a plant. In crops like ginger, turmeric, onion, garlic, gladioli, and dahlia etc. they continue to grow from buds that are present on the surface of the stem. In some plants, like sweet potato adventitious roots can give rise to new plants. In Bryophyllum and Kalanchoe, the leaves have small buds on their margins. On detachment from the plant, they are able to grow into independent plants and they may also start growing into free plants if their leaves were made to grow in the soil. In nature, vegetative reproduction occurs through underground stems, sub-aerial stems, bulbils, leaves and even roots.

9.1 INTRODUCTION When a new individual arises from a somatic cell without formation of a seed, it is called vegetative propagation. Vegetative propagation occurs naturally (i.e., natural vegetative propagation) in many crops, and profitably exploited in horticulture using either conventional or biotechnological artificial techniques. We shall discuss conventional artificial vegetative propagation in this chapter including cuttings, grafting, budding, layering, suckering, etc. They have been widely used for commercial propagation of fruit trees and ornamental shrubs.

10.1 INTRODUCTION ‘Tissue culture’ is commonly used as a blanket term to describe all types of plant cultures, viz., callus, cell, protoplast, anther, meristem, embryo and organ cultures (George, 1993). It relies on the phenomenon of cell totipotency. The different techniques of culturing plant tissues may offer certain advantages over traditional methods of propagation. Growing plants in vitro in a controlled environment, with in-depth knowledge of the culture conditions and the nature of the plant material, ensures effective clonal propagation of genetically superior genotypes of economically important plants. Micropropagation has become an important part of the commercial propagation of many plants (George and Sherrington, 1983; and Zimmerman et al., 1986) because of its advantages as a multiplication system (Pierik, 1997 and Razdan, 2003). Several techniques for in vitro plant propagation have been devised, including the induction of axillary and adventitious shoots, the culture of isolated meristems and plant regeneration by organogenesis and/or somatic embryogenesis (Williams and Maheswaran, 1986; and Gautheret, 1985). Tissue Culture is becoming as an alternative means to vegetative propagation of plants. In vitro growing plants are usually free from bacterial and fungal diseases. Virus eradication and maintenance of plants in virus free stage can also be rapidly achieved in cultures (Sharma, 2016).

Index A Acclimatization, 14, 152 Adventitious Shoot, 5, 148, 158, 159 After-Care, 21, 26 Air Layering, 3, 108, 110, 111 Anthesis, 37 Apomixis, 3, 4, 7, 52, 53, 54, 55, 56, 58 Artificial Vegetative Propagation, 4, 5, 104 Asexual, 1, 3, 6, 30, 36, 52, 54, 55, 57, 58, 66 Asexual Plant Propagation, 3, 6 Attached Methods Of Grafting, 117, 118 Auxin, 59, 80, 81, 82, 138, 139, 140, 142, 148, 150, 156, 159, 160 Axenic Cultures, 151