Bamboo and Rattan/Bamboo/Course-1 Unit-5

Block 3. Production of planting stock

BLOCK 3. PRODUCTION OF PLANTING STOCK OF BAMBOOS

Objectives: In this block we study different methods for production of planting stock of bamboos.

Introduction We have several programmes to promote bamboo industries. For any such programme whether it is small or large scale industries, it requires bamboo raw material. To have sufficient bamboo raw material we require bamboo resources. To develop bamboo resources we have to raise bamboo plantations.

Have you ever planted bamboos? If so what have you planted? Seedlings? Cuttings? Tissue cultured plants?. All these are generally known as planting stocks. From where you get your planting stock? You made it yourself or you purchased it from the nurseries in your village/city? How much you paid for it? Must be costlier than your ordinary garden plants and plantation species! You know why it is costly? Let us examine.

Did you study bamboo morphology? Do you recollect the type of growth of bamboo?. How is it? Bamboo grows for many years vegetatively by putting up of a fresh set of new shoots every year. And then what?. At the end of the flowering cycle all the bamboo flowers simultaneously. I hope you have already come across the term flowering cycle. Flowering cycle, physiological cycle, inter-mast period, all these terms refer to the duration taken for one bamboo plant from seedling to flowering stage. A seedling continues to grow vegetatively, say for about 50 years and all the seedlings originated from the same mother plant (same seed source) flower together. In short, the time taken from seed to produce seedling, grow vegetatively for the time specific to that species, flower and produce seeds is known as flowering cycle.

Have you understood that most of the bamboo flower at long interval of 40-50 years. After flowering and seed set they die. This means what? You don’t get seeds of bamboos every year and when you get seeds, the bamboos, which produced seeds, die and decay. Now you may be thinking that you have plenty of seeds and you can use it until next flowering. Sorry! Not in bamboos. Seeds can be used for seedling production only for short duration of maximum 6 months. Listen! One more shock! there are bamboos, which have not produced seeds yet. So, production of planting stock in bamboo is difficult due to absence of regular seeding and short viability of seeds. Viability is the capacity of seeds to germinate and produce normal plantable seedlings.

But we raise plantations of many species without using their seeds. Can you name some of them? How do we raise banana? By suckers. Sugar cane and Roses? By planting their cuttings. Orchids? by tissue cultured plantlets. Is it not? All these methods can be used for raising bamboo when seeds are not available. In this block, I will explain to you how we produce planting stock of bamboos, by using seeds if seeds are available and if not using other methods of propagation known as vegetative propagation. The block consists of two units – unit 1. production of planting stock using seeds and unit 2- Production of planting stock using vegetative propagation methods. The method of production of planting stock using tissue culture techniques will be dealt separately in another block.

Unit 5. Planting stock production using seeds

Objective: to study seed collection, characteristics, handling, storage and seedling production in bamboos.

Introduction You have already learned that bamboo seeds are not regularly available. To have an idea about duration of seeding, let me tell you the flowering cycle of some of the important bamboo species.

Sl. No. Species Flowering cycle (years) 1 Bambusa balcooa 35-45 2 B. bambos 45 3 B. tulda 30-60 4 Dendrocalamus giganteus 40 5 D. hamiltonii 30-40 6 D. longispathus 30-32 7 D. strictus 25-45 8 Melocanna baccifera 40-45 9 Ochlandra ebracteata 7 10 Phyllostachys bambusoides 120 11 Sinarundinaria wightiana 01 12 Thyrsostachys oliveri 48-50

Now you have seen that flowering cycle varies from one year to 120 years in different species. If you know which year the species you want to collect seeds flowered earlier, you can plan in advance to collect seeds. Otherwise when you see the onset of flowering you have to do it quickly.

I hope you have learned about sporadic flowering and gregarious flowering in previous block. Although we say about flowering cycle which is gregarious flowering, there are some out of phase flowering in bamboos which is known as sporadic flowering during which a part of the bamboo clump or some of the clumps in an area flowers . Limited quantity of seeds, which is generally inferior in quality is also available in some of the species like D. strictus, D. hamiltonii etc.

In this Unit you will be learning about type of bamboo seeds, how to collect different types of seeds i.e. different methods of seed collection, how to handle collect seeds, possible methods of seed storage, how test the viability of seeds and production of seedlings.

Types of Bamboo Seeds Do you know that there are about 110 genera and more than 1500 species of bamboos in the world. Luckily there are only three types of bamboo seeds. These types are recognized by the external appearance (morphologically). The first type is known as caryopsis. Just see the picture below. In caryopsis, the pericarp is membraneous, thin, soft and adhered to the seed coat. What it means? Pericarp is the outer covering of the seed. It is thin like a membrane and stuck to the seed coat which is the next structure below. The fruit has an apparent ventral suture, which is nearly as long as the whole fruit. Suture is a depression on one side and it is on the ventral side.

The second type of seed is known as Glans. It has hard, smooth, crustaceous pericarp separated from seed coat and no ventral suture. See the picture below.

The third type is known as Bacca. In bacca, the pericarp is fleshy and thick and separated from seed coat. Seeds of bacca type are large and below is the picture of largest bamboo seed, seed of Muli bamboo (Melocanna baccifera)

Methods of Seed collection

Have you seen any bamboo seeds?. Have you got any idea how to collect them especially from forest areas? Just think! How we collect the seeds of plants around us?. We collect fruits first, process them like drying, thrashing etc to separate seeds, which are inside the fruit. Is it not? Or we simply eat the fruit and take the seeds. But here fruits and seeds are same. One fruit has only one seed and that is the fruit itself. 

Bamboo seeds can be collected by different methods. The method you chose will depend on the type of bamboo, the area where it is grown, i.e., the terrain and the type of seed. The common methods for seed collection are given below.

Shaking of culms

How you pluck mangoes if you have a tall mango tree in your house?. Suppose the mangoes are ripe and started falling. Have you used a long pole with a hook at one end and shaken the branches?. When you do that “pada pada pado”. The ripe mangoes and even some unripe mangoes will fall on the ground. If the mango tree is small and branchy you may climb and shake the branches with your hands using all the force. The same method can be used for collection of bamboo seeds also. In species like thorny bamboo (Bambusa bambos), that are tall, 15-30 m, a long pole with a hook is needed for shaking the culms. But, manual shaking is good enough and successful in species with small sized (less than 15 m) culms like Dendrocalamus strictus. See! Mangoes are big and you can hand pick them from the ground. But if you have some seeds very small like paddy or wheat grains what will you do?. You have to clean the ground before shaking and sweep the floor to get fallen seeds. To save your energy and to get clean seeds, before shaking the culms, it is ideal to spread a tarpaulin or canvas sheet on the floor beneath the flowered clump so that collection is made easy.

Collection of fallen seeds

When bamboo seeds mature they fall near to the mother clumps. If seeds have to be collected from natural forests, clearing of the dead leaves and other debris beneath the flowered bamboo clump is essential. As mentioned earlier a plastic sheet, canvas or tarpaulin can be spread over the ground under the clumps to make collection easy. One more advantage. Seeds will not come in contact with soil which harbours lot of soil fungi that will infect seeds. Now you may ask that any way you have to put the seeds in soil to produce seedlings? Why to keep them away from soil now?. Soil fungi if they infect seed they damage the embryo and later when you saw seeds they will not germinate. Fallen seeds may preferably be collected in the afternoon. You know why? In the morning higher moisture content due to condensation of the dew drops in the previous night will be there and it will make seeds more susceptible to fungal infection.

Do you know that bamboo seeds are just like paddy or wheat and eaten by animals including man. The animals, birds etc. that eat seeds are known as seed predators. Bamboo has several seed predators. What can we do? We can protect the area with wire nets if possible. If the area is large and the bamboo is large it is not workable. Then what? Seeds should be collected in 3-5 days interval and never be left in the field for a longer period.

Another method of collection of seeds from the top portions of the clumps is usually by cutting the seed bearing culms. This method is suitable for bamboos growing on slopes and in steep undulating terrain. It should be attempted only if the quantity of mature seeds is abundant, otherwise wastage will be much higher. Anyway you don’t have to worry about the damage to the culm since the flowered clumps will die after seed set.

Please see the picture below and tell me what you see there?

This is a flowered clump of B. tulda and a green net is spread below to collect the fallen seeds as I have already described to you. Seed handling Just have a look at the seeds you have collected from the ground!. What you see. The seeds collected by sweeping the floor contain inert materials such as soil, stones, leaves, twigs of bamboos, etc. More than seeds what you are looking for you have other materials which you don’t want. Now how do you separate them? How do you clean paddy, wheat after harvest?. Do you know what is a Winnow? A bamboo mat with rim woven in particular form and using that you can separate light particles from the dense one and it is called winnowing.. Impurities like stones and seeds of other species are separated by hand picking.

(we need a hand drawn illustration or photograph of winnowing)

Now you got the seeds! What will you do? In the beginning I have already told you that bamboo seeds will germinate only for a short period. So it is better to sow the seeds soon after collection.

Suppose you have tones of seeds and you need only a small quantity now. You want to preserve them. Is it possible?. The answer is partly yes and partly no. Why it is so? Because, the preservation or storage of seeds depend on the type of seeds. You have learned in the beginning that there are three types of bamboo seeds – caryopsis, glans and bacca. Of these, the caryopsis and glans type of seeds can be stored for about 4-5 years using scientific methods of seed storage. You may be wondering why these two and why not the bacca type. Conventional methods of seed storage is by storing the seeds in controlled low temperature and low humidity for which the moisture content of the seeds need to be reduced. In short, the seeds needs to be dried. The bacca type of seeds if dried gets damaged and it can not be stored. Processing of seeds for storage Suppose you buy fruits and vegetables from market for one week and you are going to store it in your fridge. How will you do it?. You will first remove the damaged ones, next you will take the vegetables and fruits, which are easily perishable, and finally you will take the good ones. The same method is used for processing the seeds for storage. Here you cannot differentiate the good ones by simply looking at it. They all will look same. So there are some indirect methods to know the quality and the first one is viability testing. That is to test the percentage of germination of seed lot you have received.

Viability testing of seeds

Do you know how to test viability of seeds?

For testing viability four samples of 25 –100 seeds (25 seeds of bacca type and 100 seeds of caryopsis and glans types) each from each of the seed lot are to be used for sowing. You can sow the seeds in soil or use the simple method shown below.

A tray is taken and a small piece of sponge which is soaked in water (the sponge is about 0.5 cm thick and porous). The sponge is placed in the center of the tray as shown above and water is poured in such a way that the sponge is not floating on water. Seeds are placed on the sponge and the germination is observed daily and number of seeds germinated is counted. The seeds will be eaten away by rats if not protected by a wire mesh as shown below.

The percentage of germination of seeds is calculated by counting the number of seeds germinated out of 100 seeds sown. Similarly the moisture content of the seeds also needs to be determined. For this fresh weight and dry weight of seeds are determined and the difference is converted to percentage. The moisture content before storage should be around 8 per cent and the seed should have about 80 % germination for storing. The seed lots should be free from insect and fungi.

Seed storage

Two methods – using desiccants and keeping in deep freeze can be used for bamboo seed storage

Using desiccants

Seed lots initially dried to 8 % moisture content are filled in airtight plastic containers with a suitable desiccant. Anhydrous silica gel and calcium chloride are some of the commonly used desiccants. About 100 g of desiccant kept in an airtight container would be sufficient to store 1 kg seed. Some of the desiccants like anhydrous silica gel are self-indicative of their freshness and purity. It is blue in anhydrous condition and turns white with absorption of moisture. It can be reused after heating (till the blue colour is regained). Large quantities of seed can be stored in specially designed storage rooms with dehumidifiers. Keeping the seeds in relatively lower humidity condition will help to maintain the equilibrium moisture content of the seeds low. Reduction of moisture content slows down respiration and prolongs aging.

(photos of desiccants anhydrous and hydrous stage and desiccator with seeds)

In deep-freezer

A deep-freeze or cold room can be used to store seeds at lower temperature. Seeds, probably with moisture content of 8-% can be stored for about 4 years at -14 to – 10oC. Continuous power supply to the storage unit needs to be ensured at all time. Like moisture, temperature also affects seed viability. At lower temperature, rate of respiration is low and the life span of seeds increases.

Production of seedlings Now let us see how we can produce planting stock of bamboo from seeds.

Seed sowing in nurseries A site near to proposed plantation area with facilities for irrigation is the best site for nursery. There should be good drainage and availability of sun light. As already mentioned fresh seeds are the best. Direct sowing of seeds on nursery bed or dibbling of seeds in polybags can be done for raising seedlings. Though direct sowing in lines are often liable to fail due to relatively uneven germination, slow growth of resultant plants, exposure to animal damage, etc. the more usual practice is to broadcast seeds and raise the plants in nursery beds and transplant them to polybags after 30-45 days of growth in nursery beds. Then young seedlings of 3-5 leaf stage are transplanted in polybags (24 cm x 18 cm), containing about 2 kg of a mixture of sieved soil, sand and farmyard manure in the ratio 2:1:1. Usually, one to two month-old seedlings give good survival when transplanted to polybags. One to two month-old seedlings will be about 15 to 45 cm height. The seedlings are maintained in the nursery for one year before transplanting to the field.

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A view of a nursery bed spread with seeds of Muli bamboo. The seeds need to be topped with a layer of soil sand mixture.

Seedlings after poly- potting ( two weeks after sowing)

Seedling nursery of Melocanna after one- year.

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Unit 5. Through seeds

5.1. Objectives

5.2. Introduction

• Life cycle and Seeding period
• Seed types

5.3. Seed collection

• Methods of seed collection
• Shaking of culms
• Collection of fallen seeds

5.4. Seed handling

• Cleaning of seeds
• Germination test

5.5. Seed storage

• Dry storage with control of humidity
• Cold storage with control of temperature

5.6. Seed pre-treatments

5.7 Seed sowing

• Assessment of quantity of seeds
• Dibbling in poly bags
• Direct sowing in nursery beds