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close this bookAbstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)
close this folderAbstracts on seed production
View the documentAcknowledgements
View the document1. Good quality bean seed.
View the document2. A pocket directory of trees and seeds in Kenya.
View the document3. Seed production of agricultural crops.
View the document4. Seed potato systems in the Philippines: a case study.
View the document5. Seed enrichment with trace elements.
View the document6. Current practices in the production of cassava planting material.
View the document7. Alternative approaches and perspectives in breeding for higher yields.

Acknowledgements

1187 92 - 9/34

Seed production

Review, study, guide, audiotutorial unit, handbook, CIAT, developing countries, tropics, subtropics, bean seed, management, ecology, production, harvest, standards, activities, evaluation

DOUGLAS, J. et al.

1. Good quality bean seed.

Study Guide, CIAT, Apartado A_reo 6713, Cali, Colombia; Series 04eB-12.03, 1981, 36 pp.

An effective seed program comprises many and diverse elements and activities which must be coordinated to attain the principal objective: produce and distribute good quality seed of improved varieties.

Therefore, the success of a seed program is founded on producing and providing a sufficient quantity of good quality seed, at the required time, at a reasonable cost, and at a location where it is needed, so that the majority of the farmers can enjoy the benefits provided by using this seed.

This study guide is complementary material to the audiotutorial unit "Good-Quality Bean Seed". Its principal objective is to provide useful information relating to the practices of production, quality control and processing of bean seed.

The audiotutorial unit is a translation of the Spanish unit entitled "Semilla de Frijol de Buena Calidad" which was produced by CIAT through a special project on the development and utilization of training materials on improved agricultural production technology.

The handbook contains the following chapters:

- Objectives
- Introduction
- What is Good Quality Seed?
- Varietal purity
- Physical purity
- Good germination
- Freedom from seed-borne diseases
- What is needed to produce Good Quality Bean Seed?
- Varietal pure seed
- Freedom from seed-borne diseases
- A site that provides an unsuitable environment for development of pathogenic organisms
- A suitable field
- Special management of the crop
- Removal of foreign, off-type and diseased plants
- Harvest of the seed
- Steps to follow after harvesting Good Quality Seed
- Drying
- Cleaning
- Treatment
- Sampling
- Evaluation
- Storage
- Transport
- Activities of Different Groups in Obtaining Good Quality Seed
- Seed certification authorities
- Research programs
- Seed growers, seed enterprises and marketing groups
- Evaluation
- Bibliography

This handbook together with the audiotutorial unit provides useful information for the practice of quality bean production.

1188 92 - 9/35

Seed production

Review, book, Africa, Kenya, directory, seeds, trees

TEEL, W.

2. A pocket directory of trees and seeds in Kenya.

Publ. of Kenya Energy Non-Governmental Organizations (KENGO) P.O.B. 48197, Nairobi, Kenya, Repr. 1988, 142 pp.

There was a time, not so long ago, when trees were taken for granted in Kenya. There were so many, often so thick with dense undergrowth that walking through was a hard task. Today that time has gone. Trees no longer dominate Kenya's high potential land. In areas of lower rainfall and less agricultural potential, trees are disappearing rapidly, being cut for timber, charcoal, or just to clear the land. As they become more scarce, the awareness of just how important trees are, grows.

In the recent past, seed collection and distribution had been centralized through the government's relevant ministries. This continues to be the case for certain species of timber trees, such as Cypress and Pine, to ensure the best provenance selection. These government sources are not always able to deal with the wide variety and extent of today's locally rising demand. To meet this demand, it has been found that a decentralized approach to seed collection and distribution is essential.

Advice is increasingly available f.e., that is part of the function of directories like this one.

This directory is divided into six chapters:

Chapter 1: Questions and answers

A list of questions which are normally asked about species selection and seed collection is compiled. The answers given provide some basic information about choosing which trees to grow, how to collect seeds and briefly, how trees propagate. The section also includes some general information on how to store and treat seeds before sowing.

Chapter 2: Local climate type list

The range within which a tree can be planted is determined primarily by rainfall and temperature. Rainfall and temperature zones overlap but can be differentiated into a total of 33 zones in Kenya, according to the

Agroclimatic Zone map published by the Kenya Soil Survey. For purposes of simplicity, some temperature zones have been combined in the list.

The climatic types are identified with the name of the most representative town found within that type.

Chapter 3: Climate type/tree species list

For each of the climate types, this chapter provides a list of all the trees which grow, or could grow in that area. This is only a selection of trees which may be recommended with priority. It may be possible that some of these trees will grow in areas for which they are not listed.

It is almost certain that all the trees listed under a given climate type can grow in that area, but some will perform better than others.

For this reason an asterik has been placed after those species known to grow best in this climate type which is recognized as the climate zone for these species.

Chapter 4: Individual tree species profiles

This chapter provides information about each of the recommended tree species. It contains a choice of 90 tree species; indigenous, exotical and fruit, listed in alphabetical order by botanical name. Following this, for both indigenous and exotic trees, is a brief look at their uses and even briefer description of the tree itself. The preferred climatic type of the tree is then given and, if known, the most common growing sites. Next, information about the seed is provided. This includes approximate size and weight, estimated seeding time, length of viability and best germinating techniques. Last comes the list of potential seed sources to contact if seed cannot be found in the local area.

Fruit trees, because of their importance as a food source, are listed separately. The information on fruit trees is also treated in a slightly different manner. Seeds and seedling suppliers are listed by province at the end of the section. The list of fruit trees available as seedlings from these suppliers follows the provincial listing.

Chapter 5: References and resource people

This chapter is a list of sources used for the information in this book, as well as others which could be relied upon to provide further information about growing these trees. For most of the indigenous trees information is scarce, limited generally to botanical literature. There is considerable information available about fruit trees.

Chapter 6: Information exchange

This chapter gives information where to go, or whom to ask for answers.

The idea is to help spread knowledge around and this chapter suggests how to do it.

1189 92 - 9/36

Seed production

Review, developing countries, book, practical guide, agricultural crops, varieties, crop production

KELLY, A.F.

3. Seed production of agricultural crops.

Longman House, Burnt Mill, Harlow, Essex CM20 2JE, UK, ISBN 0582-40410, £27.42

It is now recognized that crop production is limited by genetic potential and that improved varieties must be the foundation of any attempts to improve yield. However, not only must seed be of high genetic potential, it must also be harvested, cleaned and stored correctly if it is to retain good germination ability and vigour for seedling growth. Seed testing may also be necessary to determine germination, vigour and presence of disease and seed treatments may be considered to protect seeds from seed - and/or soil-borne diseases.

In 'Seed Production of Agricultural Crops' A. Fenwick Kelly has written a practical guide to the basic requirements for the correct production of seed for agricultural crops and the book contains enough fundamental information to enable readers to understand the reasoning behind the management practices discussed.

The author was Deputy Director of the National Institute for Agricultural Botany in England from 1970-83, since when he has been active in international organizations dealing with seed matters and has worked as a consultant with the FAO. Although he assumes knowledge of the basic principles of crop production, his book is largely self-explanatory on all major points and will be useful to all those responsible for developing seed production in the Third World.

1190 92 - 9/37

Seed production

Asia, Philippines, case study, seed potato, physiology, pathology, production systems, CIP, GTZ

CRISSMAN, C.C.

4. Seed potato systems in the Philippines: a case study.

International Potato Center, Lima, Peru; ISBN 92-9060-136-1, 1989, 82 p.

This report is one of a series of case studies on seed potato systems in selected countries. The main objective of the individual case studies is to identify strengths and weaknesses in organized seed potato programs.

To do this effectively, the organized potato program must be examined in the context of its environment. Thus a systems approach is adopted in these studies to categorize and evaluate the role of an organized program within the larger seed system.

Potato production in the Philippines is centered in the high and mid-elevation areas of Benguet and Mountain Provinces in the agricultural region of Ilocos in Northern Luzon.

The data show a rapid expansion in production during the last ten years at an average annual rate of 8.3%. Most of that growth is explained by expansion in area and the rest is due to changes in yield.

The government efforts have centered on a cooperative project with the German government to establish a seed production scheme in the highlands of northern Luzon.

The concept of system used in this study stresses function rather than structure as the basic device by which to classify the system parts.

Special attention is paid to linkages between the different agencies which have roles in the organized seed programs and the linkages between these agencies and the informal farmer-based seed system.

The format of the report proceeds from the general to the specific.

First there is a brief discussion of trends in the potato sector and the potato in the Philippine food system in terms of production, consumption and marketing. Next is a presentation of the larger elements which influence the seed system, the physical and socio-economic environment and the government. An overview of the RP German seed potato project is presented in the discussion of government activities.

After this overview the discussion follows the chain of activities found in the Philippine seed system. These steps are:

- provision of adequate varieties

- the initial creation of seed supplies, a step crucial for overcoming the slow rate of reproduction while moving from foundation material to sufficient quantities of basic seed, and

- the building of seed supplies, which includes the organization of farmer cooperators for bulk multiplication but also for quality control.

- Next the work of the private sector is discussed, the components of crop protection and storage are introduced, and an overview and discussion of results are presented.

The gradual build up of diseases in seed stocks obliges farmers to replace their seed stock periodically. In the absence of widespread certified seed, the source of the replacement seed requires careful consideration. In developing countries this usually means that seed from higher altitude zones would be preferred. Thus there often exists a distinctive flow of seed from one location to another. Once on the farm, the farmer can use various methods to slow the rate of degeneration of the seed. These methods include proper post-harvest handling and storage, field or post-harvest selection, and pre-planting treatment.

1191 92 - 9/38

Seed production

Latin America, Brazil, study, field trials, maize, field bean, trace elements

PRIMAVESI, A.

5. Seed enrichment with trace elements.

In: Proc. of the 8th Int. IFOAM Conference, Budapest, Hungary, 1990, pp.131-133

Little or no attention is given to seed nutrition. It is considered that, automatically, seeds, produced by plant breeding, may give rise to healthy, vigorous plants. If this does not occur, soil is improved by heavy NPK application, and agro-toxics have to protect the high yielding crops attacked by pests and diseases.

The author worked with copper enrichment to paddy seeds and found that only plants of treated seed responded to a copper fertilization; seeds of plants fertilized with copper did not respond to enrichment. Paddy with copper gave higher yields, had a better grain quality, breaking on seldom when husked, and had a strong resistance to Pirucularia oryzae.

Even in fields infected with Piricularia oryzae and planted with infected seeds, no diseased plant appeared.

Seed treatment of maize and beans was very efficient. The soil roots of maize, given boron to seeds, are deeper. Spodoptera frugiperda attack was reduced to 2% instead of 55% on the test plots. Nearly all plants had two to three ears. Ears were greater and grains heavier. During storage of six months, no worm attacked. With zinc sulphate there was no attack of Elasmopalpus, which killed 20% of the seedlings on the testplot. Zinc additionally to the soil made the plants more drought resistant.

Seed enrichment to field beans protected them against parasites when followed by two leave applications, whilst the test plants had to be sprayed with pesticides five times. Those plants with seed enrichment and leave fertilization did not need to be protected.

It is assumed that plant protection against parasites by seed enrichment and trace element fertilization may be due to the nutritive effect.

Micronutrients are enzyme activators or part of the prosthetic group or incorporated in the enzyme itself. A stronger enzymatic activity may be assumed as facilitating the formation of organic substances improving the biological value of plants.

The seeds could be treated with a surprisingly high concentration of multi saline solution. It may be supposed that trace elements in balanced proportion with others, like iron-manganese or copper-molybdenum may be used in much higher concentrations without a toxic reaction. On the other hand, even potash is toxic in mono saline solution.

It may be concluded that well-nourished or enriched seeds are more resistant against parasites. Plant health may be improved by seed enrichment and micronutrient fertilization. At the same time this increases yield and biological quality. Crop production with enriched seeds is less expensive and risky than conventional agricultural technology.

1192 92 - 9/39

Seed production

Review, tropics, cassava, planting material, production methods, stakes, cutting methods, mukibat system, handling, chemical treatment, CIAT,

CIP, IITA,UNDP

LEIHNER, D.E.

6. Current practices in the production of cassava planting material.

In: Proc. of a Reg. Workshop, Cali, Colombia, 1983, pp. 41-45

This paper reviews some of the current practices in stake production and points out some elements necessary for improvement.

Selection of stakes:

A conscientious selection of mother plants according to nutritional and health status, followed by a careful selection of stakes from these plants, is hardly ever done in traditional production systems.

In traditional systems, hardly any selection is made with regard to the maturity of the stake. This means that along with stakes of adequate maturity (recognized by a relation of total to-pith diameter of between 2:1 and 3:1), a large number of either too young, i.e., succulent stakes, or too old, i.e., very lignified stakes, are selected. This leads to plant loss and a patchy, uneven sprouting of stakes.

Cutting and preparation:

- Cutting methods:

A great variety of cutting methods are presently practiced worldwide. In one of the common methods, the long stem is placed on a base.

- Stake length:

As with cutting methods, farmers use a great variety of stake lengths in commercial plantings. Stakes as short as 10 cm with only two to four buds may be used by some, whereas others cut and plant stakes of 40 cm or more.

- Mukibat system:

The traditional and rudimentary methods of selecting and preparing cassava planting material stand in contrast to a very careful and elaborate system known as the Mukibat system. A well-selected Manihot esculenta stake is used as a stock onto which a Manihot glaziovii scion is grafted.

Handling before planting:

- Transport:

The majority of cassava planting material is transported in the form of long stems to facilitate handling and reduce moisture loss.

- Chemical treatment:

Chemical treatment of stakes for pest control and protection against soil-and air-borne fungi after planting is not a common practice among cassava producers. Many farmers simply do not know about this way of stake protection.

Concluding cassava planting material is obtained in a very simple manner from low-value raw material and probably for this reason no refined stake production technology has developed among farmers. It is suggested that in order to improve stake production technology, the primary considerations are selection of stakes for healthiness and adequate maturity, non-damaging cutting practices and the use of appropriate stake lengths.

1193 92 - 9/40

Seed production

Review, ideotype breeding, Australia, alternative yield improvement

MARSHALL, D.R.

7. Alternative approaches and perspectives in breeding for higher yields.

Field Crops Res., 26, 1991, pp. 171-190

This paper considers strategies for increasing commercial yields of crops by plant breeding, both directly by increasing yield potential, and indirectly by improving the expression of yield potential in practice.

Little attention was given to crop improvement by considering morphological or physiological traits which could directly contribute to higher yields. Whilst his ideotype approach has generated considerable interest, there has been limited adoption of ideotypes in breeding programmes, and limited success in terms of yield improvement.

The development of model plants or ideotypes has been adopted as a major breeding philosophy by relatively few programmes. The reason for this is that most breeders have formed the view that the ideotype approach offers no advantage over the available alternatives, in terms of yield improvement in their crops. Breeders may have reached this conclusion either because of perceived difficulties or disadvantages with the ideotype approach, or perceived advantages of alternative approaches.

This is discussed in this paper in relation to conceptual and practical difficulties in the implementation of ideotype breeding, including the difficulty of identifying yield-enhancing traits, and the lack of genetic diversity for such traits in some agricultural crops.

Alternative strategies for yield improvement include using techniques such as heterosis in FI hybrids, and the identification and manipulation of individual 'yield' genes (particularly using the recombinant DNA technology of restriction fragment length polymorphisms (RFLP). However, an emphasis on the 'defect elimination' approach to plant improvement will continue to be relevant, as many Australian farm crops yield well below their genetic potential. Substantial progress is likely to be made by addressing the control of air- and soil-borne pathogens, mineral deficiencies and toxicities, appropriate phenology, and resistance to frost damage during heading in cereals.

Increased yield is regarded by most plant breeders as an important, high-priority objective. There are two ways commercial yields can be increased by plant breeding:

- Directly, by increasing yield potential per se above that of standard varieties in the same environment. This may be done by increasing total dry-matter production, or by increasing the proportion of the total dry-matter converted to economic yield, or both; or

- Indirectly, by improving the extent to which the true yield potential of a crop is realized in practice. This may be done by genetically removing or overcoming biotic (e.g. diseases and pests) or abiotic (e.g. frost, drought, salinity, mineral deficiencies or toxicities) constraints on crop production.