Breeding method of crop fungal disease permanent disease-resistant compound train

Abstract

A breeding method of crop fungal disease permanent disease-resistant compound train includes: firstly acquiring the etiology strain of the target crop diseases and the corresponding disease-resistant genetic resources; switching disease-resistant gene in each disease-resistant genetic resource in the skeleton parent, for breeding complemented anti- spectrum breeding intermediate material; using the breeding intermediate material to breed conventional breed near isogenic line or hybrid female parent and male parent near isogenic line with complemented anti- spectrum and identical other characteristics, distributing the disease-resistant genes to each near isogenic line; mixing the near isogenic line conventional breed with complemented anti- spectrum for production, or mixing the female parent near isogenic line with complemented anti- spectrum as the female parent, the male parent near isogenic line with complemented anti- spectrum as the male parent, and then producing the cross-fertilize seeds according to the usual cross-fertilize seed production method. Compound train breed prepared by the invention is applied in the production, which can improve the flexible degree of the crop resistance, realize the crop permanence resistance, meet the scale, standardization and commercialization requirements of the modern agriculture and extend the service life of the breed.

Description

technical field [0001] The invention belongs to the selection and breeding of plant varieties, in particular to the cultivation of crop varieties with long-lasting resistance to fungal diseases. Background technique [0002] After long-term evolution and variation, the types of pathogenic physiological races of crop fungal diseases are abundant, and the number of pathogenic genes is huge. For example, there are 8 groups of rice blast and hundreds of physiological races. 16 races have been found, which is one of the most common diseases on corn. Therefore, it is of great significance to carry out research on new methods of fungal disease-resistant breeding. [0003] The theory of gene-to-gene vertical resistance is the genetic theory of fungal disease resistance generally accepted by academic circles. First, crop resistance genes or defense response genes can resist the infection and expansion of pathogens in the process of crop resistance response. There is also a correspon...

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Problems solved by technology

Third, the functional units of disease resistance are equally important, function in parallel, and cannot replace each other

[0005] However, at present, the improvement of crop varieties resistant to fungal diseases faces two outstanding problems. First, the adaptability is too poor

The current promotion varieties do not have the ability to resist the attack of multiple physiological races, and it is difficult to promote the varieties cultivated in one rice area to another rice area

For example, Chuanxiangyou 3 was approved as a new variety with high resistance in Sichuan, but it became a high-susceptibility variety after it was introduced into Fuling, Chongqing, causing disasters and epidemics with huge losses

Second, the resistance is not durable

There are four main reasons for this result: first, few antigens, narrow resistance spectrum, differences in resistance gene resources, breeding time, financial investment, technical support, and the difficulty and speed of biological evolution of crops and pathogenic bacteria Restricted by factors such as rice blast, it is very difficult to introduce all resistance genes into the same variety. So far, no variety resistant to all rice blast physiological races has been bred.

Second, the systematic improvement of crop resistance is lagging behind. In the farmland ecosystem, systematic improvement of crop resistance is required objectively. The disease-resistant gene must fully cover the disease-causing gene, and all functional units must be of the disease-resistant type. Otherwise, As long as one functional unit belongs to the disease-susceptible nature, the overall resistance of the crop will become a disease-susceptible type; however, the past disease-resistant breeding work is just the opposite. We increase some disease-resistant functional units to solve the problem of disease resistance in dominant races. The main goal is that most of the functional units are still susceptible, and the resistance spectrum is always narrower than that of the disease nursery; the large-scale planting of such varieties will inevitably produce differential selection pressure on the pathogenic bacteria, and the internal population structure balance of the pathogenic bacteria will be broken. Susceptible functional unit—secondary physiological race develops rapidly and evolves into a dominant physiological race, and variety resistance fails

Fourth, the resistance ecosystem is single. The resistance spectrum of the individual plants of the existing vertical resistant varieties is homogeneous. The resistance spectrum of the ecosystem composed of individual plants is single and unstable, and the resistance intensity is rigid. Yes, either resistant or susceptible, no intermediate levels of resistance at all

However, its resistance breeding is aimed at the dominant physiological race of pathogenic microorganisms at the time of breeding, and uses specific plant genes that can resist the dominant race. High resistance level, once the variety is popularized on a large scale, under the strong selection pressure of vertical resistance of resistant varieties, the mutation speed of pathogenic microorganisms will be accelerated, some inferior races will be transformed into dominant races, and the emergence of new physiological races will be accelerated, so that Rapid conversion of resistant varieties into susceptible varieties causes huge losses to crops; therefore, varieties bred using this method of disease-resistant breeding lack persistence of disease resistance

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