What are traditional breeding techniques like?

1. Live breeding

Through the fruit tree seed propagation, produce natural variation, to select it, in order to improve the genetic composition of the fruit tree population (or individual), so as to get the favorable horticultural traits of the population varieties (or nutrient varieties) of the breeding method is the live breeding, the oldest history of a variety of breeding methods, suitable for a variety of fruit tree crops.

From the history of live seed selection, its specific methods can be divided into: the original live seed selection and modern live seed selection. The former does not pay attention to parental traits before selection, but only pay attention to the performance of the live offspring, from the methodological point of view, it lacks the necessary theoretical guidance, blindness, randomness, the method itself is simple and easy to implement, in the history of human seed selection can not be erased.

Modern live-breeding selection, guided by the theory of genetics (especially population genetics), has a strong purpose and predictability. In essence, it is through live breeding to select different generations, so that favorable genetic traits genes accumulate in individuals, so as to obtain advantageous individuals (or advantageous individuals composed of advantageous groups). The most useful and simple selection method in fruit trees is to select multiple individuals with known favorable traits as parents based on their phenotypes, let them randomly mate with each other, and then select the superior types among the progeny, a method also known as group selection (Mass selection).

From today's fruit tree genetic breeding point of view, some long to live breeding rough management of fruit trees, such as walnut, chestnut, mountain apricot, etc., live breeding technology is still a very valuable method of application. In other fruit trees, can be borrowed from the live breeding technology to obtain new germplasm resources. Especially in the utilization of some wild resources, seeds can be collected first and then useful individual types can be selected among their sown progeny. Of course, it is also a necessary path in the future development of emerging wild fruit trees, as in the history of human resource utilization.

2. Natural mutation seed selection

Nature in the bud meristem organization body cell mutation, mutated cells form mutated tissue (chimeras), which further formed bud change (mutated bud), and when the mutated bud sprouting into branches, until the flowering and fruiting, the performance of the new traits, and is also known as the branching change. According to this characteristic, people consolidate the good somatic cell variants through asexual reproduction (such as grafting), and then pass on the expansion to form new asexual varieties, this breeding technique is called bud variation selection.

The genetic basis of bud mutation is limited to mutations at individual gene loci, so the basis of variation is small, and the role of local improvement for the promoted varieties is large. Such as the U.S. red compact marshal line of new varieties, are obtained through the marshal of the bud variation selection.

3. Cross-breeding

With known traits of different species as parents, through artificial control of pollination and fertilization, to obtain hybrid offspring, and then select the best varieties (or strains) of cross-breeding methods, is the biggest breakthrough in human breeding achievements. Crossbreeding of fruit trees began in the 19th century, and the method has been used as the mainstay of breeding methods for hundreds of years.

The genetic basis of crossbreeding lies in: on the one hand, it can concentrate the favorable genes of both parents, i.e., the additive effect produced by gene recombination; on the other hand, it can use the ecological and geographic origins of the more distant species (or varieties) interbreeding, and its progeny of the accumulation of the number of loci of compound alleles, and the non-additive effect produced by gene recombination and so on. This gene exchange and recombination brings about a wide range of genetic variation and ample opportunities for breeding selection. From the point of view of resource utilization, this method has a very important role in creating new types of resistance by importing favorable genes from wild relatives into cultivars, in addition to using cultivars for further improvement. It is this characteristic of cross-breeding methods, so that breeders have been holding an optimistic idea, that is, any cultivation problems caused by varieties can be solved through breeding methods.