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Seed is the primary input for any productive forestry and afforestation programme. The global communities around the world are looking for increasing forest tree cover for both environmental amelioration and livelihood purpose. These both issues are possible when we have quality seed and planting material. Larg quantities of seeds are needed every year to raise the nursery stock for propagating the desired plant material. Hence a plentiful supply of quality seed is therefore one of the prerequisites to make such activities successful. Seeds are also one of the important sources of germplasm conservation and methods of harvesting, collection, storage and other properties need to assessed on scientific grounds. Seed viability varies from species to species and is affected by various locality factors and physiology. Seed testing and certification is important for quality seed production and storage. In view of the increasing demand for quality seed production of various afforestation programmes and the numerous challenges in various seed processing steps, the present book is very important for the students to learn the basic concepts of seed science. The present volume deals with the basic concepts of forest seed science including testing.

Seed bearing plants Seed-bearing plants are broadly categorized in two major types: the gymnosperms and the angiosperms which are together grouped in Division Spermatophyta in the older system of classification for the plant kingdom. Consequently, seed plants are presently classified into multiple phyla. Still, for the purpose of learning basic concepts, it is convenient to group plants informally as spermatophytes (sperm "seed" + phyte "plant"). The spermatophytes are the most complex and evolutionarily advanced plants. Unlike ferns and bryophytes which reproduce and disperse by unicellular spores, spermatophytes reproduce and disperse by means of multi-cellular seeds which consist a protective seed coat surrounding an embryonic sporophyte and its food supply. This group of seed plants exhibits an alternation of generations in which the sporophyte is dominant. Furthermore, the gametophyte is microscopic and heterosporous with the latter term meaning that these seed plants produce two types of spores: microspores and megaspores that give rise to separate male gametophytes (micro-gametophytes) and female gametophytes (mega-gametophytes) respectively. The megaspore is never released from the sporangium; thus, the female gametophyte develops within the sporangium while being still attached to the sporophyte.

The collection of cones/fruits and seeds is the first step in the harvest, processing, and storage of seed in which man interacts with nature in determining ultimate seed quality. Successful collection, therefore, depends on understanding seed maturation and dispersal characteristics of each species, knowing local weather trends, and evaluating crop quality. Collection of propagating material is an expensive process and it is therefore also important that areas wherein cones and seeds are to be collected are evaluated to determine whether a sufficiently heavy crop to permit economic collection of seeds is present and whether the seed zone and elevation represented by the candidate area is appropriate for the production of seedlings needed in the reforestation program. Remember that properly collected, processed, and stored seeds may remain viable for a decade, so evaluation of seed needs may be projected well in advance of current harvest schedules through proper planning and organization of seed collection.

The decision whether to extract the seed from the fruit at a central seed processing depot or close to the site of, and soon after, collection must be made in the light of local conditions. The reduction in bulk and weight of the collected material greatly facilitates transport and for this reason the extraction of the seed from relatively bulky fruits may be desirable at the site close to the collection area. In some cases it has also been found that early extraction of the seed is essential to maintain maximum viability. The use of the sun drying to speed extraction of the seed is common for many conifers and trees with woody dehiscent fruits. However, too rapid drying of fruits may sometimes cause them to remain closed and prevent later extraction, a condition known as “case-hardening” of cones. This is true for the cones of some pines if they are collected before peak maturity. In such cases it is necessary to keep the fruits under cover, with a good circulation of air, for one or two weeks before more rapid drying is attempted.

Seed dormancy Plants evolve many mechanisms that ensure their survival. For instance, some species produce prodigious number of seeds so that even if only a small proportion germinate and grow, some seedlings will survive. Alternately, dormancy can be defined as: a seed characteristic, the degree of which defines what conditions should be met to make the seed germinate. This definition may be more useful in understanding dormancy because it suggests that dormancy is variable, rather than constant, which is the situation that we generally encounter in the native populations of many species. The staggering of germination (dormancy) is an advantage for seeds that mature in late summer to early fall, since immediate germination would leave vulnerable seedlings exposed to harsh winter conditions.

Seed testing No matter how good processed seed may look, the actual value is the number of seedlings it will produce. Testing of seeds is therefore imperative to determine and identify the changes that have occurred from the time of collection until the seeds are sold or sown at one time. The critical step in evaluating a seed lot is the drawing of representative sample. Place all the test samples in a bucket, mix them thoroughly and subdivide to obtain sample size. Improvements in seed processing can only be obtained with quality control. These evaluations should be made in the processing plant and at a seed testing laboratory. The National Tree Seed Laboratories offers a free service to evaluate processing machinery. You need only collect a small sample of seed after it has been processed by each machine and send it to the laboratory. Be sure all the seed comes from the same lot so all samples are related. Each machine must be adjusted for efficient operation, and proper adjustment requires monitoring of the operation.

Need for certification Forest restoration and reforestation experts know the effect the right seed source can have on the long-term economic and ecological success of tree planting efforts. However, unlike stock quality (such as size and health), genetic quality (seed source) cannot be observed by the consumer at the time of stock purchase. Where once the provincial government controlled the source of seed and its destination through the provincial nursery system, seed supply is now in the private sector, and the source is unknown or a matter of trust. Tree planting in general needs help, and the wrong seed source is only one of the many reasons that your planting project may not be successful. Besides, the identity of the source will be tracked throughout the chain of custody until it is presented, as a labeled, certified product to the consumer. The seed source may be from a single parent tree or preferably from a large healthy stand of trees. But if seed is bulked from many locations, the label on the resulting seedlings can only indicate the greater area. For example if a nursery bulked its seed from many counties across a specific place, they can only certify and market that crop as? specific place? not as one from a specific county that may have been a source for the seed. For this reason we will have to encourage collectors and growers to bulk only by tree seed zones to promote certification program for the context of successful tree planting.

A Angiosperm 2, 6 Acanthaceae 2 Archegonia 6, 7, 8 Abscission 13 Apical 20 Artificial 28, 41, 62, 63 Aqueous 79, 80, 81, 83