Month: September 2023

Seeds are like tiny just-add-water kits for new life. They contain an embryo and starchy food, all kept safe inside a protective shell. Some seeds need special light or temperature conditions or a period of dormancy to spring into action.

Cecilia Zumajo and her colleagues are studying how seeds take that first step from dormancy to seedling. Their research is helping us understand gene networks that control seed development and evolution.

What is a seed?

A seed is a miniature plant in a state of arrested growth (called dormancy) with stored food for its future development. Its food is contained within a nutrient reserve called endosperm that can be made of starch, carbohydrates or proteins. It is protected by a seed coat and its outer shell.

A seed can also have a tiny hole, called the micropyle, through which water and nutrients enter the embryo. This allows for the process of imbibition, which reactivates enzymes in the seed that converts storage compounds into usable nutrients. This process is important to the plant’s germination. After germination, the seed can grow into a mature, reproducing plant that will produce more seeds and continue the cycle of life. Seeds vary in size, shape and color. They are often able to remain dormant, or inactive, for years until conditions are right for them to grow. This is one of the reasons gardeners can plant heirloom varieties, which tend to “grow true” or produce offspring that resemble the parent plants.

What are the parts of a seed?

A seed contains an embryo and food reserve enclosed in a protective outer covering. Under favorable conditions seeds give rise to a new plant. There are three main parts of a seed; the seed coat, the endosperm and the embryo.

The seed coat is typically hard, thick and brown in color. It consists of two layers; the outer layer is known as the testa and the inner layer as tegmen. The hard seed coats prevent germination of the embryo in unfavorable environmental conditions.

Inside the seed coat lies a soft, water-absorbent tissue called the endosperm. It stores carbohydrates, proteins and other nutrients for the embryo. The cotyledons, which can resemble tiny leaves or be fleshy, provide nourishment to different parts of the embryo during germination. There is a single cotyledon in monocots and two in dicots. The embryo contains the genetic instructions for the new plant. It is surrounded by the cotyledons and the endosperm.

How do seeds grow?

Seeds need a lot to grow into a plant: Water, the right temperature, and sunlight. They also need a food store–which most seeds have inside them, called endosperm. The food stores all the carbohydrates and protein the embryo needs to start growing.

Once a seed has the right conditions it can grow roots and become a tiny seedling. The process is called germination.

The seed coat lets water into the embryo, which then swells up and splits open. The embryo grows into a tiny plant, with one or more leaf-like parts, called cotyledons.

The cotyledons give the seedling nourishment until it can make its own food, using sunlight and water, through photosynthesis. The seed also has a food reserve, stored in the embryo, that it can use until its leaves are large enough to get food from outside the seed.

How do seeds disperse?

Seeds can’t move themselves, so they rely on external entities to hitchhike them around the landscape—wind, water and animals. Seeds dispersed further away from the parent plant are more likely to survive, as they have less competition with siblings and parents, better access to light conditions and avoidance of predators and pathogens.

Wind dispersal (anemochory) is the most common method of seed transport. For example, the feathery pappus that opens and catches the wind on a dandelion can transport its seeds far from its parent plant. Similarly, maples use winged fruits (samaras) that flutter to the ground on winds.

Some plants also make their seeds a bit more attractive to potential dispersers by enclosing them in fleshy fruit that is appealing to animals, such as squirrels. The seeds may have hooks or burs that catch on fur or feathers, or they might have structures designed to break open under the force of a bird’s beak.

As the popularity of feminized seeds grows, some growers are asking why Sensi Seeds still carries regular cannabis seeds. The simple answer is that we believe there are certain situations where regular seed will prove more advantageous than feminized.

Regular seed produces male and female plants in a natural ratio of 50/50. For breeders this is ideal because it preserves genetic stability and allows for phenotype variation.

Stability

Regular seeds preserve genetic stability, making them an ideal choice for breeders who want to explore new strains or maintain consistency in existing ones. Unlike feminized seeds, which are produced by forcing a female plant to produce male plants through artificial means, regular seeds allow the grower to select only the desired female plants for breeding.

The ability to select only female plants can lead to a higher yield than a typical feminized crop, as the grower will not have to cull the majority of her plants due to being male. This can be a major benefit to growers who wish to maximize the amount of buds they can harvest and recoup their growing costs.

However, because regular seeds can produce both male and female plants, growers must be sure to sex their crops promptly and remove any male plants. Failure to do so can result in cross-pollination, reducing the yield and quality of your crop.

Breeding

Regular cannabis seeds operate just as Mother Nature intended. They have a 50% chance of emerging as either male or female plants, which allows growers and breeders to create new cultivars and produce superior clones. During cultivation, growers can take advantage of hermaphroditism by brushing pollen from a male plant onto a female plant to fertilize it and create hybrids.

This method of breeding can yield great results. For example, growing a male plant with a female can accelerate flowering and increase the crop’s potency. You can also experiment with blending strains to create unique cultivars. For instance, mixing an indica and sativa can result in a balanced strain with unique terpene profiles. This can be a great way to explore the potential of a new strain or add extra flavor and aroma to an existing one. However, be careful not to overdo the breeding or you could end up with hermaphrodites or other undesirable traits.

Phenotype Variation

Regular seeds are a great option for experienced growers who want to preserve the genetics of their preferred strain. They offer a lot of flexibility in terms of plant size and flowering time, and can produce both male and female plants. However, they do have a higher chance of producing hermaphroditic plants, which can cause unwanted pollination and a decrease in overall crop quality. Therefore, careful monitoring is required to identify and remove hermaphroditic plants.

Variation in seed size and number is a key trait for crop fitness, but genetic factors influencing these traits remain largely unknown (Sadras 2007). The natural variation observed in both seed size and seed number in wild accessions of A. thaliana provides an ideal model for studying the genetic architecture of these traits. However, to date, most studies of gene-by-gene variation in seed traits have focused on mutant screens. In this study, we use a QTL mapping approach to explore genetic variation in both seed weight and seed number and their interaction with other life-history traits.

Cost

Unlike feminized seeds, regular seeds operate exactly how nature intended. This means every seed has a 50% chance of emerging as a male or female plant. The advantage of this is that cultivators can use the male plants for breeding.

Male plants are valuable because they contain pollen sacks that can fertilize the female colas and produce seeds. This process produces new cultivars and helps maintain the genetic integrity of a strain.

From a financial perspective, regular seeds are cheaper to produce than feminized ones. This makes them a popular choice for growers who prefer the challenge of culling male plants from their crop.

With a wide selection of high-quality regular cannabis seeds, you’ll find the perfect cultivar to suit your needs. Whether you’re looking for a citrusy sativa like Amnesia Lemon or a therapeutic indica such as Harlequin x Bubba Kush, our collection has something to suit every taste.

Before feminized seed became a reality, regular seeds were the preferred option for growers looking to cultivate new strains. Like their feminized counterparts they offer many advantages but do require careful sexing to ensure that all female plants are harvested.

This process requires time, effort and expertise to identify male plants and remove them. However, sexing plants becomes easier over time as they age.

Breeding

The frequency with which good seed years occur varies considerably. The occurrence of good seed crops can be improved by preventing deficient pollination, by thinning to improve vigour, by increasing foliar nutrition and by providing protection from climatic dangers, cone-destroying insects and animals and fruit-damaging fungi.

Comprehensive national certification schemes for tree seed and plants are now in operation in most countries. The object of these is to maintain and make available to practicing foresters seeds, plants and propagating materials of superior provenances or cultivars and to guarantee their quality.

These national schemes require large seed pools, and so can have a limited impact on the diversity of cultivated varieties. This is a constraint on breeding: both public and private breeders need to be able to multiply their new varieties with a reasonable amount of seed, while maintaining the high standard of seed quality. This requires that some phenotype variation is reduced by selection, cloning or other means.

Cloning

Clones are cuttings taken from a vegetative mother plant, which makes them an exact genetic copy of the original plant. While clones provide greater security with their genetics, they also require a more complicated growing process.

The cloning process begins with the selection of a healthy plant to take a cutting from. This mother can be purchased from a cannabis breeder or obtained from your current garden. It is important to select a sexless, or hermaphrodite, plant as male plants will produce pollen sacs, which detract from the bud yield.

Once the desired branch is selected, it is cut from the parent plant and immediately placed into a cup of water. Allowing air to reach the cut end for more than a few seconds can result in an irreparable air embolism and damage the clone.

Rooted clones are then planted into soil or a hydroponic medium. It is recommended that you use a balanced plant nutrition solution to help the clones establish roots.

Genetic Stability

Genetic stability is an important attribute required for the production of regular seed. Seeds age over time, resulting in a loss of viability and quality. This process is associated with different genetic modifications such as point mutations, DNA fragmentation and accumulation of reactive oxygen species (ROS).

A high level of genetic stability in a regular seed crop can be achieved by following strict genetic management practices. These practices include promoting fertility uniformity and synchronization.

In mammalian production cell lines that express a transgene, the genetic stability of the cells is essential. This is evaluated during the molecular characterization of the production cell bank. This is a requirement by regulatory bodies worldwide. Genetic instability results in mutations that may impact the final vaccine product. These mutations can result in the deletion, rearrangement or replacement of genomic sequences that are required for the correct expression of a gene. In addition, they can result in a change in the cell phenotype or expression profile that is not desired for the vaccine product.

Phenotype Variation

As with all living organisms, phenotype variation is the consequence of basic heritable genetic variance and environmental influence. Heritable variation is produced through mutation, gene flow, and sexual reproduction. Environmental influence occurs when individuals move into or out of a population and interact with others in new environments.

Phenotypic variation is an essential part of the evolutionary process. It enables natural selection to function. Without phenotypic variation, there can be no evolution through natural selection.

A good example of phenotypic variation is the coloration of Labrador Retrievers. Although labradors are genetically all the same, they can be any color from black to yellow to brown. This is a result of environmental influences such as food, water, shelter and exposure to the sun. Similarly, the growing conditions of cannabis plants can cause a variation in phenotype. For instance, hermaphroditis can occur if the plant is irrigated with salty water or exposed to intense heat and light.