A plant breeding technique in which the
The bagging technique involves covering the stigma with bags. This process ensures pollination with pollens from the preferred male parent.
The removal of the bag from flowers is not known as rebagging. When pollen are dusted on the stigma of flowers, they are again covered by bags till fertilization occurs, this step is known as rebagging.
Bagging is a process used in plant breeding to prevent self pollination in bisexual flowers . Anthers from bisexual flowers are removed and this act of removing anther is called emasculation and then flower is covered with a paper bag to prevent contamination from unwanted pollens .
Emasculation – Emasculation is the process of artificial hybridization where the pollen and anthers of the flower are separated to prevent self-pollination. Bagging – Bagging involves covering the emasculated flower with a bag to prevent pollinating agents from reaching it.
Bagging offers the advantage of allowing many weak learners to combine efforts to outdo a single strong learner. It also helps in the reduction of variance, hence eliminating the overfitting of models in the procedure. One disadvantage of bagging is that it introduces a loss of interpretability of a model.
Bagging of the emasculated flowers during hybridisation experiments is essential to prevent contamination of its stigma by undesired pollen grains.
Bagging is also a technique of covering the stigma with bags to prevent contamination of stigma from pollens. This technique is mainly practiced to ensure pollination with pollen from the desired male parents during the breeding program.
Bagging is usually applied where the classifier is unstable and has a high variance. Boosting is usually applied where the classifier is stable and simple and has high bias.
Bagging as Mechanical Isolation
So, bagging is exactly what it sounds like; the female flower is covered with a bag so that pollinators such as insects can't get to her and do the pollination dance. In the case of tomatoes and peppers, the flowers are “complete”, so you'd cover any flower.
Bagging is a physical protection method which not only improves the visual quality of fruit by promoting skin colouration and reducing blemishes, but can also change the micro-environment for fruit development, which can have several beneficial effects on internal fruit quality.
In artificial hybridisation procedures, stigma has to be protected from any unwanted pollen, so it is covered with bags made of butter paper.
Ambu. [edit on Wikidata] Use of manual resuscitators to ventilate a patient is frequently called "bagging" the patient and is regularly necessary in medical emergencies when the patient's breathing is insufficient (respiratory failure) or has ceased completely (respiratory arrest).
Reduce the occurrence of fruit diseases and insect pests: bagging can effectively reduce the occurrence of fruit diseases and insect pests. This reduces pesticide use and prevents birds from stealing the fruit once it is ripe.
The key idea of the proposed method is that bagging is combined with feature selection to improve the accuracy and diversity of a set of learnt classifiers. The underlying reason is that to construct a set of classifiers, bagging repeatedly resamples the training dataset to build a set of training resampled datasets.
Bagging attempts to reduce the chance of overfitting complex models. It trains a large number of “strong” learners in parallel. A strong learner is a model that's relatively unconstrained. Bagging then combines all the strong learners together in order to “smooth out” their predictions.
Bagging is classified into two types, i.e., bootstrapping and aggregation. Bootstrapping is a sampling technique where samples are derived from the whole population (set) using the replacement procedure. The sampling with replacement method helps make the selection procedure randomized.
Reducing Variance with Bagging
Bagging aims to produce a model with lower variance than the individual weak models. These weak learners are homogenous, meaning they are of the same type. Bagging is also known as Bootstrap aggregating. It consists of two steps: bootstrapping and aggregation.
Bagging gives equal weight to each model, whereas in Boosting technique, the new models are weighted based on their results. In boosting, new subsets of data used for training contain observations that the previous model misclassified. Bagging uses randomly generated training data subsets.
Breiman developed the concept of bagging in 1994 to improve classification by combining classifications of randomly generated training sets.
Advantages of Bagging
Reduces variance, so has a strong beneficial effect on high variance classifiers. As the prediction is an average of many classifiers, you obtain a mean score and variance. Latter can be interpreted as the uncertainty of the prediction.
Hint: Emasculation is the process of removal of male reproductive organ of a flower. It is mainly done in bisexual or monoecious plants.
Emasculation is done during early morning between 6 and 8 AM in spikelets, due to open on the same day. Emasculation should be over well ahead of the time of anthesis. Crossing techniques in rice differ based on the method of emasculation.
The anthesis, emasculation and actual crossing are preferably done early in the morning or late afternoon because blooming occurs early in morning & stigma receptivity is high & it is also done during evening because most of the anther dehisce during evening.