Types of Seeds
The Wonderful World of Seeds
With delicate care provided by farmers, seeds germinate and grow from seedlings to mature plants gradually. Some seeds eventually turn into delicious vegetables dishes. Meanwhile, some of them go through flowering and fruiting, producing a new batch of seeds. Seed is not only the origin of our food, but also the way that plants start and complete their life cycles. Seed have been fulfilling our daily needs. They have a wide variety of shape and colour. The followings are some of the popular vegetable seeds:
Family: Brassicaceae
Examples: Chinese Cabbage, Chinese White Cabbage, Chinese Kale, Broccoli
Seed characteristics: small and round, dark colour (black, reddish-brown, dark brown, etc.)
Family: Asteraceae
Examples: Lettuce, Indian Lettuce
Seed characteristics: flat, elongated oval with pointed ends, brownish grey or greyish white
Family: Solanaceae
Examples: Tomato, Eggplant, Chilli, Bell Pepper
Seed characteristics: small and flat, kidney-shaped or round; yellowish brown, pale yellow or beige; some varieties have hairs
Family: Cucurbitaceae
Examples: Wax Gourd, Water Melon, Pumpkin, Bitter Melon
Seed characteristics: large and flat, ovoid, hard seed coat, a variety of colours (beige, black, brown, white, etc.)
Family: Fabaceae
Examples: Soybean, Asparagus Bean
Seed characteristics: visible hilum on the side, hard; round, kidney-shaped or ovoid; a variety of colours (pale yellow, pale green, black, reddish brown, etc.)
Remarks: The above information is for reference only. Morphology of seeds varies from species to species.
Seed Reproduction
There are different modes of reproduction in plants – asexual reproduction (making use of tuberous root, rhizome, leaves, etc.), and sexual reproduction (production of seeds). Prior to seeds saving, it is crucial for farmers to understand clearly the types of pollination of crops. This could reduce the risk of pollen contamination and hence ensure the quality of seeds.
Self-pollination:
Pollen is transferred from the anther to the stigma of the same flower, or another flower on the same plant. Species with self-pollination has a low natural crossing rate. This would lead to the production of offspring with lower genetic variation that the characteristics or traits of parents could be retained effectively. Farmers are not required to take any management measure on isolation when growing the crop.
Examples: Lettuce, Tomato, Asparagus Bean, Okra, Roselle
Cross-pollination:
Pollen is transferred from the anther to the stigma of another plant of the same species. Species with cross-pollination is unable to accept pollen from the same plant. Insects and wind are the major pollinating agents. Since higher genetic diversity could be resulted from cross-pollination, adaptability of the crop to environmental variation could be enhanced. Isolation measures must be taken by farmers when planting, such as keeping a certain distance between species of the same Family, separating the flowering season of different species, planting the crops inside net houses with the aid of artificial pollination, etc.
Examples: (Insect pollination) Chinese Cabbage, Watercress, Radish, Cucumber, Spring Onion; (Wind pollination) Corn, Spinach
Types of Seed
Mode of Production
Commercial Variety
Landraces
Introduction
The variety is selected and produced by the seed companies. Seeds have high distinctiveness, uniformity and stability. A universal name of the variety is required.
Landraces are formed by a long-term grower selection and natural selection. Seeds are saved by farmers for several generations and have not subjected to formal plant breeding. Landraces are often closely related to traditional culture or customs.
Characteristics
✔ high quality of seed (yield, germination rate, purity, etc.), which is suitable for commercial production
✔ high consistency of the variety
✘ Farmers could not save seeds from hybrid crop and need to purchase hybrid seeds from seed companies every year
✘ Seed companies tend to concentrate resources on developing core crop products, reducing the number of varieties available in the market
✘ Seed companies may apply for patents on traits of crops for certain products, limiting the seed saving work conducted by farmers
✔ Higher genetic diversity, thus greater resistance to stress (diseases, pests, drought, flooding, etc.)
✘ Lower yield, difficult to meet market demand
✘ Lower uniformity, difficult to be commercial products
Commercial Variety
Introduction
The variety is selected and produced by the seed companies. Seeds have high distinctiveness, uniformity and stability. A universal name of the variety is required.
Characteristics
✔ high quality of seed (yield, germination rate, purity, etc.), which is suitable for commercial production
✔ high consistency of the variety
✘ Farmers could not save seeds from hybrid crop and need to purchase hybrid seeds from seed companies every year
✘ Seed companies tend to concentrate resources on developing core crop products, reducing the number of varieties available in the market
✘ Seed companies may apply for patents on traits of crops for certain products, limiting the seed saving work conducted by farmers
Landraces
Introduction
Landraces are formed by a long-term grower selection and natural selection. Seeds are saved by farmers for several generations and have not subjected to formal plant breeding. Landraces are often closely related to traditional culture or customs. /p>
Characteristics
✔ Higher genetic diversity, thus greater resistance to stress (diseases, pests, drought, flooding, etc.)
✘ Lower yield, difficult to meet market demand
✘ Lower uniformity, difficult to be commercial products
Mode of Reproduction
Hybrid Variety
Open Pollinated Variety
Introduction
It is also known as “F1 Hybrid”. They are produced by the crossing of two different parents with stable inbred lines.
Variety could be produced from self-pollination or cross-pollination. Traits of parents and offspring are consistent.
Characteristics
✔unique combination of desirable traits inherited from both parents
✘ Desirable traits start to dimmish starting from the second generation. Seed quality would be greatly reduced.
✘ F1 Hybrids are commercial varieties. Farmers need to purchase hybrid seeds from seed companies every year.
✔ Farmers could save seeds on their own
✘ Since species with cross-pollination has a higher genetic diversity, different isolation measures must be taken when saving seeds
Hybrid Variety
Introduction
It is also known as “F1 Hybrid”. They are produced by the crossing of two different parents with stable inbred lines.
Characteristics
✔unique combination of desirable traits inherited from both parents
✘ Desirable traits start to dimmish starting from the second generation. Seed quality would be greatly reduced.
✘ F1 Hybrids are commercial varieties. Farmers need to purchase hybrid seeds from seed companies every year.
Open Pollinated Variety
Introduction
Variety could be produced from self-pollination or cross-pollination. Traits of parents and offspring are consistent.
Characteristics
✔ Farmers could save seeds on their own
✘ Since species with cross-pollination has a higher genetic diversity, different isolation measures must be taken when saving seeds
Why should we conserve landraces?
- In the past, Hong Kong produced a number of famous crop products, such as “Hok Tau Chinese White Cabbage”, “Yuen Long See Mew Rice”, “Chuen Lung Watercress, etc. However, most of them have been lost.
- Increase crop diversity, and provide consumers with diversified agricultural products
- Higher genetic diversity and higher adaptability to local environment. Farmers could reduce the use of pesticides and fertilizers. More environmentally-friendly
- Greater resistance to stress could help adapt to climate change, ensuring food safety
- Enhance farmers’ breeding and seed savings techniques
- Conserving landraces contribute to inheritance of local traditional culture, customs and agricultural techniques
- Promoting Locally saved seeds could help promote the development of local agriculture