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Seed and different methods of sowing
- 1. Shoolini University Dr. Arshdeep Singh Department of Agronomy
- 2. (A) Seed and different methods of sowing
- 4. Definition- Seed is a fertilized ripened ovule consisting of three main parts namely seed coat, endosperm and embryo, which in due course gives raise to a new plant. Endosperm is the storage organ for food substance that nourishes the embryo during its development. Seed coat is the outer cover that protects or shields the embryo and endosperm. • Seed is a fertilized ovule consisting of intact embryo, stored food (endosperm) and seed coat which is viable & has got the capacity to germinate. • Seed is any material used for propagation whether it is in the form of seed (grain) of food, fodder, fiber or vegetable crop or seedlings, tubers, bulbs, rhizomes, roots, cuttings, grafts or other vegetatively propagated material. • The formation of the seed completes the process of reproduction in seed plants (started with the development of flowers and pollination), with the embryo developed from the zygote and the seed coat from the integuments of the ovule.
- 7. Characteristics of good quality seed Seed is the basic input in the crop production which should be of good quality. 1. Seed should be genetically pure & should exhibit true morphological & genetical characters of the particular strain (True to type). 2. It should be free from admixture of seeds of other strains of the same crop or other crop, weeds, dirt and inert material. 3. It should have a very high & assured germination percentage and give vigorous seedlings. 4. It should be healthy, well developed & uniform in size. 5. It should be free from any disease bearing organisms i.e. pathogens. 6. It should be dry and should contain 12-14% moisture.
- 8. Seed germination • Epigeal Germination – Cotyledons are exposed above ground – Epicotyl and hypocotyls are also visible – Cherry, soybean, radish • Hypogeal Germination – Cotyledons are buried in the ground – Only epicotyl are visible – Peach, pea, apricot Two Different Types of Germination
- 11. SEED RATE Seed rate is the quantity of seed required for sowing or planting in an unit area. The seed rate for a particular crop would depend not only on its seed size/test weight, but also on its desired population, germination percentage and purity percentage of seed.
- 12. Sowing Time:Sowing is the placing of a specific quantity of seeds in the soil for germination and growth while planting is the placing of plant propagules (may be seedlings, cuttings, rhizomes, clones, tubers etc.) in the soil to grow as plants. .Follow recommended sowing dates. 1. Optimum time of sowing for Kharif crop – June or July 2. Optimum time for Rabi crop - last week of October to first week of November Any fluctuation in optimum sowing time results in drastic yield reduction. E.g. Wheat. Depth of Sowing: It influences the germination & emergence of seed. Bigger seeds may be sown at a greater depth while small sized seeds at shallow. Seed should be dropped in the moist zone. In Kharif, sowing should be shallow and in Rabi deeper except pre-sowing irrigation. The optimum depth of sowing for most of field crops ranges between 3-5 cm. • Shallow depth of sowing of 3-5 cm is enough for small seeds like sesame, finger millet and pearl millet. • Very small seeds like tobacco are placed at a depth of one cm. Bold seeded crops like castor, groundnut, cotton, and maize etc. are sown at 6-7 cm depth.
- 13. Sowing methods 1.Broadcasting 2.Dibbling 3.Drilling 4.Sowing behind the country plough 5.Planting 6.Transplanting
- 14. Broad casting - Broad casting is the scattering or spreading of the seeds on the soil, which may or may not be incorporated into the soil. Broadcasting of seeds may be done by hand, mechanical spreader or aeroplane. Broadcasting is the easy, quick and cheap method of seeding. The difficulties observed in broadcasting are uneven distribution, improper placement of seeds and less soil cover and compaction. As all the seeds are not placed in uniform density and depth, there is no uniformity of germination, seedling vigour and establishment. It is mostly suited for closely spaced and small seeded crops. Eg. Sesamum, methi, coriander, etc. are sown by this method.
- 15. Dibbling - It is the placing of seeds in a hole or pit made at a predetermined spacing and depth with a dibbler or planter or very often by hand. Dibbling is laborious, time consuming and expensive compared to broadcasting, but it requires less seeds and, gives rapid and uniform germination with good seedling vigour. eg. Castor, and Hy. Cotton
- 16. Drilling - It is a practice of dropping seeds in a definite depth, covered with soil and compacted. Sowing implements like seed drill or seed cum fertilizer drill are used. Manures, fertilizers, soil amendments, pesticides, etc. may be applied along with seeds. Seeds are drilled continuously or at regular intervals in rows. It requires more time, energy and cost compared to broadcasting, but maintains uniform population per unit area. Rows are set according to the requirements
- 17. Sowing behind the country plough - It is an operation in which seeds are placed in the plough furrow either continuously or at required spacing by a man working behind a plough. When the plough takes the next adjacent furrow, the seeds in the previous furrow are closed by the soil closing the furrow. Depth of sowing is adjusted by adjusting the depth of the plough furrow. e.g., ground nut sowing in dry land areas of Tamil Nadu.
- 18. Planting Placing of vegetative part of crops which are vegetatively propagated in the laid out field Tubers of Potato, mother sets of ginger & turmeric, cuttings of sweet potato & grapes, sets of sugarcane
- 19. Transplanting - Planting seedlings in the main field after pulling out from the nursery. It is done to reduce the main field duration of the crops facilitating to grow more number of crops in an year. It is easy to give extra care for tender seedlings. For small seeded crops like rice and ragi which require shallow sowing and frequent irrigation for proper germination, raising nursery is the easiest way. eg. Paddy, vegetable, crops, tobacco, etc.
- 20. Vegetative propagation in field crops
- 21. Plant propagation: Plant propagation is the process of creating new plants from a variety of sources: seeds, cuttings, bulbs and other plant parts. Sexual propagation Asexual propagation Seeds and spores can be used for reproduction Vegetative reproduction uses plants parts such as roots, stems and leaves Seeds are typically produced from sexual reproduction within a species, because genetic recombination has occurred. A plant grown from seeds may have different characteristics from its parents Plants are produced using material from a single parent and as such there is no exchange of genetic material, therefore vegetative propagation methods almost always produce plants that are identical to the parent.
- 22. Advantages and disadvantages of Sexual and Asexual propagation Sexual Propagation Advantages Less Expensive Many parts can be produced quickly Crosses result in hybrid vigor Avoids passing on some diseases Disadvantages Not true to type to mother plants Take more time to come to bearing Pose problems for efficient management Asexual Propagation Advantages Less time is required to produce a saleable (fit for sale) plant Plants are genetically identical The only way to produce some plant varieties Disadvantages No, new variety can be evolved Transmit viral diseases from plant to plant. Plants are comparatively short lived Requires technical skill
- 23. Techniques for vegetative propagation include: 1. Air or ground layering 2. Grafting 3. Micropropagation 4. Stolon's or runners 5. Storage organs such as bulbs, corms, tubers and rhizomes 6. Striking or cuttings
- 24. Layering is a means of plant propagation in which a portion of an aerial stem grows roots while still attached to the parent plant and then detaches as an independent plant. Layering has evolved as a common means of vegetative propagation of numerous species in natural environments. Layering is also utilized by horticulturists to propagate desirable plants. Ground layering- Ground layering or mound layering is the typical propagation technique for the popular Malling-Merton series of clonal apple rootstocks, in which the original plants are set in the ground with the stem nearly horizontal, which forces side buds to grow upward. eg. Guava Air layering- In air layering , the target region is wounded, or a strip of bark is removed and then encased in a moisture-retaining medium such as sphagnum moss, which is further surrounded in a moisture barrier such as plastic film. eg. pomegranate
- 25. Grafting is a horticultural technique whereby tissues from one plant are inserted into those of another so that the two sets of vascular tissues may join together. This vascular joining is called inoculation. The technique is most commonly used in asexual propagation of commercially grown plants for the horticultural and agricultural trades. In most cases, one plant is selected for its roots and this is called the stock or rootstock. The other plant is selected for its stems, leaves, flowers, or fruits and is called the scion or cion. The scion contains the desired genes to be duplicated in future production by the stock/scion plant Eg. Mango, Sapota
- 26. Stolon: A Creeping, Aboveground Stem: A stolon or runner of Bermuda grass (Cynodon dactylon). The stolon is an above-ground, trailing stem that typically produces roots at the nodes where leaves and stems arise. Perennial grass also produces creeping, underground stems called rhizomes. Another plant that spreads by means of stolons is the strawberry.
- 27. Micropropagation is the practice of rapidly multiplying stock plant material to produce a large number of progeny plants, using modern plant tissue culture methods. Micropropagation is used to multiply novel plants, such as those that have been genetically modified or bred through conventional plant breeding methods. It is also used to provide a sufficient number of plantlets for planting from a stock plant which does not produce seeds, or does not respond well to vegetative reproduction
- 28. By Storage organs such as bulbs, corms, tubers and rhizomes a) bulbs Eg. Onion Eg. Garlic b) By Tubers Potato
- 29. c) By Rhizome in Ginger(Zingiber officinale) d) By corm in Gladiolus
- 30. Plant Propagation by Stem Cuttings Propagation by stem cuttings is the most commonly used method to propagate many woody ornamental plants. Stem cuttings of many favorite shrubs are quite easy to root. Typically, stem cuttings of tree species are more difficult to root.
- 31. Leaf cuttings- Vegetative reproduction in Kalanchoe pinnata
- 32. (B) Crop density and different crop geometries
- 33. Plant density is the number of plants per unit area in a cropped field. It indicates the size of the area available for individual plant. Crop geometry is the pattern of distribution of plant over the ground or the shape of the area available to the individual plant, in a crop field Importance (a) Plant Density and Yield: Biological yield increases with increases in plant density up to a point and reaches a plateau with further increase in density, thus no additional biological yield can be obtained. On the other hand, the economic yield increases with increase in plant density up to a point and subsequently decreases with increased in density. (b) Plant Density and Growth: Plant height increase with increase in plant density due to competition for light. Dense plant stands leads to reduction in leaf thickness and alters leaf orientation. Dry matter production per unit area increase with increase in plant density up to a limit, as in biological yield.
- 34. CROP GEOMETRY Crop geometry refers to the shape of the space available for individual plants. It influences crop yield through its influence on light interception, rooting pattern and moisture extraction pattern. Crop geometry is altered by changing inter and intra-row spacing (Planting pattern). Wider spaced crops have advantage under this geometry • Plants which requires no restriction in all directions are given square geometry • Usually perennial vegetations like trees/shrubs are under this arrangements
- 35. (i) Square planting - Square arrangements of plants will be more efficient in the utilization of light, water and nutrients available to the individual plants than in a rectangular arrangement.
- 36. (ii) Rectangular planting - Sowing the crop with seed drill, wider inter-row and closer intra-row spacing leads to rectangularity. Rectangular arrangement facilitates easy inter cultivation. Rectangular planting mainly suits annual crops, crops with closer spacing etc., the wider section (row) is given for irrigation, intercultural operation etc. • It is an arrangement to restrict the endless growth habit in order to switch over from vegetation to the productive phase. • This method accommodate high density planting • It can facilitate intercropping also.
- 37. (iii) Triangular planting - It is a method to accommodate plant density under perennial/tree crops. (iv) Miscellaneous planting - In rice and ragi transplanting is done either in rows or at random. Skipping of every alternate row is known as skip row planting.