Production of Quality Planting Material of Horticultural Crops: Precautions and Opportunities
Author: A. K. Trivedi
ICAR - National Bureau of Plant Genetic Resources
Regional Station Bhowali - 263 132, District - Nainital (Uttarakhand)
India is endowed with rich diversity of flora which makes the country botanist's paradise. This is supported by ample diversity of agro-climatic conditions prevailing in the different regions of CHR. Vegetation in Himalayan Region is entirely different from vegetation available in Indo-Gangetic plains and peninsular India. In spite of recent developments in agricultural engineering and farm equipments mechanization of agriculture is still meagre in whole country with exception of certain regions. Farmers opt for subtropical fruits crops like mango, guava, banana, litchi in the northern plains, bael, ber, jackfruit, khejri in arid areas and almond, apple, apricot, peach, pear, plum, walnut etc., in temperate regions of Himalayan states. Although traditional fruit crops cultivation has been going on for centuries but commercial horticulture has been of recent origin. Emphasis has been shifting from bulk production to quality of produce and from total income to per unit return. Awareness among farmers and liberalisation of economy has given an impetus to the entrepreneurs for establishing export oriented horticulture. One of the most important factors contributing towards high productivity of fruit crops is quality planting material. Shortage of quality planting material is the major bottleneck in the production of horticultural crops. There is immense scope of employment and income generation through production and supply of quality planting material of horticultural crops. But lack of awareness and technical know-how for production of quality planting material hampers fruit production. Therefore, still farmers prefer to purchase planting material rather than producing their own. This can be overcome by increasing awareness and applying simple techniques which farmers can learn easily.
For easy transportation of inputs and plants a good transport network must be available to nursery site. The area should be levelled and protected from wind. The land must be reasonably well drained to avoid problems that arise from water logging. Soil of the site must be fertile and free of stones and diseases. Assured and reliable source of water for irrigation must be available. The propagation area should provide accurate growing conditions for the seedlings and plants. Every plant must be easily accessible for daily operations. There should be adequate store and tool sheds. Hardening sheds should be near the propagation area. Potting benches should be well positioned. A separate media preparation area should be available. In order to protect tender seedlings and plants from animals and to minimize unauthorized entry fencing is required. Footbaths should be placed at entrances to all propagation sites and facilities.
Stock plants or mother plants from which material for propagation (such as cuttings, suckers and bud wood for grafting and budding) can be obtained must be available near the propagation area. In this way a nurseryman will be able to supply enough and the appropriate type of planting material. Stock plants are required for producing many shoots quickly in order to get plenty of cuttings. It is beneficial to have them near so that cuttings can be collected and set on the same day. Rapid growth is desirable for production of plenty of shoots to give good cuttings and to replace nutrients lost by pruning. Stock plants need timely pruning to keep them producing shoots. These plants need frequent watering to ensure rapid and successful establishment and to encourage them to grow quickly and produce more cuttings. Stock plants need proper supply of nutrients or food to support fast growth. Nutrients are supplied by mulching; inter planting with nitrogen fixing plants and application of fertilizer and manure.
Furthermore, good nursery plant growth and development requires a soil substrate that may consist of several components such as site soil, forest soil, sand, well composted organic matter or certain materials like sawdust or vermiculite that may enhance the quality of the mixture. It should be light in weight to facilitate transport. It should holds cuttings and seedlings in place and does not shrink or swell in a way that damages the plant. Soil substrate should have a good water drainage capacity. It should retain water but allows proper drainage and aeration of the roots. It should contain essential nutrients to allow plant growth and development. It should be free from pathogens (weed seeds, fungi, bacteria and insects) and should be able to be sterilized without changing its characteristics.
Furthermore, nursery tools play crucial role in successful propagation of plants. Therefore, these should be simple but of good quality. Sometimes it is important to spend bit more on their purchase than having low quality tools. Their proper maintenance is one of the main activities of a good nurseryman. Knives, secateurs etc should be kept clean and sharpened at all times. Tool handles should not be too big or too small and that they are made from smooth material so that the nursery workers can work more comfortably and injuries minimized. Watering cans or hoses with nozzles or sprinklers should be used to apply water evenly to the plants.
In addition, for successful nursery operation proper planning is essential. When plants are needed at a specific time, all nursery operations need to be undertaken considering delivery period. If the number of plants required is known i.e., target is fixed, the amount of seeds or other stock, as well as the amount of nursery substrate can be calculated and planned properly. The most crucial event determining the right time for planting out is the availability of sufficient moisture. Another point of consideration is the use of seedlings or vegetative material. Cuttings often require less time in the nursery until they have the sufficient growth.
Many times plants prepared in the nursery cannot perform well in the farmer's field. However, nurseryman needs to have more interaction with persons who are using the plants so that they can see how the plants are performing in the field and how better plants can be produced. Therefore, feedback of farmer's is important for production of quality planting material.
Planting material can be produced by two methods
(i) Vegetative or asexual means and
(ii) Seeds or sexual methods.
Vegetative propagation refers to the propagation of new plants directly from existing ones and not from the seeds. There are many different methods used in vegetative propagation. By vegetative propagation plants of desired properties can be obtained quickly. These plants mature and fruit early. Grafting is an important method of vegetative propagation of plants. This involves the joining of a piece of stem of bud (the scion) to another plant (the rootstock) to provide root systems for detached pieces from a selected plant. Scion is a short piece of the shoot containing several dormant buds which when united to the rootstock will comprise the upper part of a grafted tree. Root stock is the lower part of the graft, which develops into the root system of the grafted tree. Grafting and budding methods are useful for the plants that cannot be readily propagated by other means as cuttings or layers. Moreover, it is useful for obtaining the benefits of the rootstock, hastening the reproductive maturity of a plant and repairing damaged parts of trees. Layering is another method of vegetative propagation where roots are caused to form on a stem which is still attached to the parent plant. The rooted stem is then detached to become an independent plant growing on its own roots. Layering is mainly used for the propagation of plants whose cuttings do not root easily, production of large sized plants in a short time, production of plants with the minimum propagation facilities. In addition, rooting of cuttings is usually done by encouraging roots to form on a piece of stem. The rooted cuttings will later become an independent plant. Cuttings can either be softwood or hardwood. Softwood cuttings are taken form softer shoots; these dry up faster and they need to be kept in a humid poly propagator or under mist until they root and can take up sufficient water. Hardwood cuttings or leafless cuttings are larger and of firmer wood, they do not dry up fast and can survive in moist soil till roots are formed. It is easier to root leafless cuttings. Pieces of stems are just pushed into holes dug in the ground, preferably in moist lightly shaded conditions. During hot dry weather simple temporary shading could be placed over them. Quick; rooting of cuttings depends on several factors, viz., turgid cuttings root better than wilted cuttings, rooting media must be moisture retaining but open and well drained, shade may be provided to reduce transpiration until rooting begins. Rooting hormones help in better establishment of cuttings.
Some precautions must be taken into account during sowing of seeds such as sterile soil or media should be used in seedbeds; pockets or trays. Trays or pockets must be filled and leveled. Lines should be marked in trays and seedbeds and the seeds should be sown thinly. If the seed is too small, it should be mixed with fine sand to ensure even distribution. Seed should be covered lightly but fine compost should not be used as this might cause caking surface. Grass mulch may be used to cover the trays, pockets or beds. Trays, pockets or beds should be irrigated regularly. Proper care must be taken when watering. Fine nozzle should be used. As seedlings begin to appear, grass covering should be removed. After germination prickling of seedlings is an important operation which must be done timely. Prickling out involves moving seedlings from a seedbed or containers where they have germinated in large numbers. The purpose of this operation is to have seedlings grow singly per container. This helps to produce healthy seedlings that grow vigorously because of the removal of competition. This operation has to be carried out under shade or in overcast weather conditions. As seedlings grow in seedbeds, pockets or trays they should be pricked out into larger pots in order to develop well. If delayed, plants become over crowded and lose vigour. Seedlings should be transplanted or pricked when the first two leaves are open. Day before pricking out, seedbed and pots should be thoroughly watered to facilitate the operation. Only healthy, well-developed seedlings should be pricked out and unsatisfactory ones should be discarded. Always hold the seedlings by their leaves and never by their stems, which are delicate. In case of long roots they should be cut using a sharp knife. A stick should be used to make hole in the soil in receiving containers.
It is advisable to keep the nursery neat and clean to facilitate operations and avoid the harboring of pests by weeds and other forms of rubbish. A firebreak against the risk of externally started fires should be maintained around nursery. It is advisable to wash nursery tools after use and store tem in cool dry place. A very important aspect of nursery management is the keeping of records on all activities of the nursery. This information helps in planning, monitoring and decision-making.
Some of the important records to be kept include
(i) Dates of planting
(ii) Operation or activity schedules
(iii) Products targets
(vii) Disease and pest control measures
(viii) Distribution of output etc.
After all successful marketing of plants is important and crucial for income generation. Therefore, for marketing general appearance of the plant in pots should be good. Consistency in quality and grade should be maintained and wilting of plants at the market should be avoided. All the plants should be properly labeled. Labels should show - botanical name and common name of the plant and the address of the producer.
Quality planting material requires quality nursery management. Most of the time farmers neglect this very important fact. Quality seedling production is necessary for quality plant production. Planting material produced under poor conditions will never perform too well when it is established in the field. The goal of a successful nurseryman is the timely and cost efficient production of healthy, uniform plants with a strong and fibrous root system that will enable the plant to get established quickly in the field.
About Author / Additional Info:
Senior Scientist, ICAR-National Bureau of Plant Genetic Resources, Regional Station Bhowali