merlubroza
Member
I improvement methods, mass selection
Greetings, we will try to explain the first and simplest method of improving plant called mass selection. this method requires a single variety and what is intended in general to improve a characteristic of an ecotype by selection and crossing of the best individuals.
It should first of all take a look at the post of genes and characters of this forum as this type of improvement is used for quantitative traits (which are measured by a number). In particular it increases in such genes are improved additives of a character.
A quantitative trait is controlled by many genes. if for example the height we immediately understood that there are many genes that influence this character.Well the effect is additive to tell us that the greatest amount of additive genes will give us a larger plant.
If a gene is heterozygous additive will give the plant size, if in homozygous plant will give us an even bigger and so for the large number of genes that may regulate the character height for example.
Well the goal of mass selection is to obtain a plant containing the highest number of additive genes for improving the character.
And we are coming more rolls:
The first thing we think is that character that we want to improve and how we will measure it in order to select plants with certain criteria.
In this example we will make a higher plant selection and the variable we will use is the height in centimeters.
the next step is to choose the plant that we want to improve. would be cool if possible a stable ecotype in this case we choose a thai for example.
We planted 125 plants in the same conditions and let them grow up that start to bloom. we measure all the data and pass them to a frequency histogram will give us the typical Gaussian bell. these data we took the mean and standard deviation. (with Excel is a fart).
For example we have a population of plants thai between males and females with an average height of 200cm and a standard deviation of 50cm.
Here we set the selection criteria, remove all plants not exceeding 230 cm and those that do leave to exceed that cross between them.
Once the seeds ripen pick and choose at random 125.
plant them again in the same conditions as the first generation plant and measured when they start to bloom. We put the data into a histogram and took the mean and standard deviation of this new generation. For example in this new generation have an average height of 220cm and a standard deviation of 20 cm.
Well if you get this is that plants are being improved and so this character has what is called heritability. followed as in the first case, selecting plants exceeding 230cm and eliminate those that do not exceed.
allowed to cross and we were with 125 random seeds obtained cycles and so on who want to keep going to slowly fixing the additive genes.
This enhancement method is simple and convenient to do so in ecotype before getting into another method of improving the formation of hybrids. if they were transported to human would select the highest to cross themselves and so prove to expect the highest seed.
Also seen from a different point of view what we are doing is eliminating the lowest.
well then this can be applied to all types of characters: yield, THC, days of flowering, pest resistance, a narrow water ... it all depends on the variable to select, measure and selection criteria.
The selection criteria is important to stay with at least 10% of the total plants because if we were to say 5% (eg if we select taller than 250cm in the example), we are left with very few individuals and we problems of low genetic variability and other hand problems of inbreeding.
Greetings, we will try to explain the first and simplest method of improving plant called mass selection. this method requires a single variety and what is intended in general to improve a characteristic of an ecotype by selection and crossing of the best individuals.
It should first of all take a look at the post of genes and characters of this forum as this type of improvement is used for quantitative traits (which are measured by a number). In particular it increases in such genes are improved additives of a character.
A quantitative trait is controlled by many genes. if for example the height we immediately understood that there are many genes that influence this character.Well the effect is additive to tell us that the greatest amount of additive genes will give us a larger plant.
If a gene is heterozygous additive will give the plant size, if in homozygous plant will give us an even bigger and so for the large number of genes that may regulate the character height for example.
Well the goal of mass selection is to obtain a plant containing the highest number of additive genes for improving the character.
And we are coming more rolls:
The first thing we think is that character that we want to improve and how we will measure it in order to select plants with certain criteria.
In this example we will make a higher plant selection and the variable we will use is the height in centimeters.
the next step is to choose the plant that we want to improve. would be cool if possible a stable ecotype in this case we choose a thai for example.
We planted 125 plants in the same conditions and let them grow up that start to bloom. we measure all the data and pass them to a frequency histogram will give us the typical Gaussian bell. these data we took the mean and standard deviation. (with Excel is a fart).
For example we have a population of plants thai between males and females with an average height of 200cm and a standard deviation of 50cm.
Here we set the selection criteria, remove all plants not exceeding 230 cm and those that do leave to exceed that cross between them.
Once the seeds ripen pick and choose at random 125.
plant them again in the same conditions as the first generation plant and measured when they start to bloom. We put the data into a histogram and took the mean and standard deviation of this new generation. For example in this new generation have an average height of 220cm and a standard deviation of 20 cm.
Well if you get this is that plants are being improved and so this character has what is called heritability. followed as in the first case, selecting plants exceeding 230cm and eliminate those that do not exceed.
allowed to cross and we were with 125 random seeds obtained cycles and so on who want to keep going to slowly fixing the additive genes.
This enhancement method is simple and convenient to do so in ecotype before getting into another method of improving the formation of hybrids. if they were transported to human would select the highest to cross themselves and so prove to expect the highest seed.
Also seen from a different point of view what we are doing is eliminating the lowest.
well then this can be applied to all types of characters: yield, THC, days of flowering, pest resistance, a narrow water ... it all depends on the variable to select, measure and selection criteria.
The selection criteria is important to stay with at least 10% of the total plants because if we were to say 5% (eg if we select taller than 250cm in the example), we are left with very few individuals and we problems of low genetic variability and other hand problems of inbreeding.