8 results about "Directional selection" patented technology

The invention discloses a breeding method and application of fragrant soft rice two-line hybrid rice with an off-white anti-counterfeiting mark, and belongs to the technical field of rice breeding. According to the method, soft rice genes with recessive grey white endosperm markers, genic male sterility character genes and the like are subjected to synchronous phenotype aggregation directional selection for the first time, the problem that the genic male sterility character and excellent taste quality character are difficult to synchronously select in the earliest segregation generation is solved for the first time, and in addition, the technical link of taste quality detection and identification can be saved; the selection efficiency is improved; meanwhile, the problem that the taste quality and control genes thereof need to be detected and identified for multiple times during mating and parent selection of high-quality hybrid rice is solved for the first time; besides, the soft rice character gene with the recessive grey white endosperm marker is synchronously introduced into a two-line hybrid rice parent, through main target character aggregation response identification, the fragrant soft rice two-line hybrid rice with the grey white marker and the aromatic flavor is successfully created for the first time, the yield is increased, and infringement and loss of independent brand fragrant rice products can be prevented.

The invention discloses a wheat haploid accurate identification and breeding method based on molecular markers, and belongs to the technical field of agricultural biology. The method comprises the following steps: hybridizing a created multifunctional haploid induction line HIP-Plus serving as a male parent with a target female parent, and saving immature embryos to obtain seedlings; a three-stage identification system comprising visual preliminary screening, molecular confirmation and early selection is adopted to carry out accurate screening on seedlings: firstly, preliminary screening is carried out based on embryo color, then haploid confirmation and transgenic component detection are carried out by utilizing TaMTL allele specific markers, and finally genetic typing is carried out through important character function markers to screen out elite haploids; and carrying out chromosome doubling to obtain a double haploid homozygous line. According to the method, the haploid identification accuracy is improved, the breeding period is shortened, the early directional selection of the target agronomic traits in the haploid stage is realized, and the breeding efficiency and accuracy are greatly improved.

Provided are a high-stability recombinant type I collagen and a use thereof, relating to the technical field of collagens. By means of the directional selection of existing amino acid sequences, potential enzyme cutting sites and unstable sequence fragments are avoided during sequence design, enabling efficient expression in Pichia pastoris; and in addition, after being purified, the recombinant type I collagen still has high stability. The recombinant type I collagen takes into account factors such as related biological active sites and hydrophilicity, has related biological activity while maintaining high stability, and has good practicability.

The invention provides a breeding method of a drought-resistant and high-temperature-resistant millet variety. The breeding method comprises the steps of parent selection, cross pollination, F planting and screening, F and offspring planting and multi-generation screening, stable strain identification and the like. According to the method, parents with obvious drought resistance and high temperature resistance are selected for hybridization, drought stress and high temperature treatment are set in different growth stages, quality screening is combined, and the millet strain with stable characters is bred in multiple generations. The method can accurately and directionally select, accelerates character stability and shortens the breeding period. The bred millet variety has the characteristics of drought resistance and high temperature resistance, the yield reduction range is small under the high-temperature drought condition, and the quality is good. According to the method, the breeding efficiency is improved, the grain yield and quality are guaranteed, agricultural sustainable development is promoted, and the requirement of the market for the high-quality stress-resistant millet variety is met.

The invention discloses a directional breeding method for high-temperature-resistant offspring seeds of crassostrea sikamea. The directional breeding method comprises the following steps: determining a medial lethal temperature LT50 and selecting parents. According to the directional breeding method for the high-temperature-resistant offspring seeds of the crassostrea sikamea, the semi-lethal temperature LT50 of the crassostrea sikamea is measured, the high-temperature-resistant parents are screened at the semi-lethal temperature LT50 and used for breeding high-temperature-resistant strains of the crassostrea sikamea, and the method has the advantages of being simple, efficient, scientific and reliable. According to the method disclosed by the invention, a mode of combining multi-gradient temperature stress and an SPSS logistic regression model is adopted, the median lethal temperature LT50 is accurately positioned as a key screening temperature, and individuals which still can survive at the median lethal temperature LT50 are directly screened as breeding parents, so that a technical support is provided for directionally breeding the crassostrea sikamea high-temperature-resistant strain; according to the method, genetic improvement of the heat resistance character of the crassostrea sikamea can be more accurately achieved, high-temperature-resistant fries are obtained, and therefore the survival rate of the crassostrea sikamea at the high temperature frequently occurring in summer is increased.

The invention relates to the technical field of crop breeding, and discloses an efficient breeding method for directionally improving comprehensive characters of winter wheat, which comprises the following steps: step (1) cross parent selection and preliminary gene polymerization; (2) early generation gene pool construction and high-pressure disease resistance screening; (3) high generation selection and homozygous acceleration; (4) identifying the eurytopic adaptability of multiple ecological regions; and (5) carrying out directional selection on agronomic characters in the whole growth period. According to the method, a single-spike continuous selection strategy is adopted in F2-F4 generations, compared with traditional single plant selection, more inter-plant variation can be contained, gene differences in the same plant can be reserved, a breeding material gene pool is enriched, recessive excellent gene loss caused by only paying attention to external forms is avoided through collaborative screening of agronomic phenotypic characters, early stress resistance and quality preliminary screening, and the breeding quality is improved. The polymerization probability of high-yield, high-quality, disease-resistant and other target genes is remarkably improved, the pain point of waste of early generation gene resources in the traditional breeding technology is effectively solved, and a solid gene foundation is laid for multi-character collaborative improvement; f5 and above ear row / single plant rapid homozygous stable new materials and guarantee the uniformity of offspring, the breeding efficiency can be improved, and provincial and above regional tests can be participated 2-3 years in advance.

The invention relates to the technical field of cotton variety breeding, and particularly discloses a saline-alkaline-tolerant, high-quality and high-yield cotton variety breeding method which comprises the following steps: S1, parent selection and hybridization: taking an upland cotton germplasm A with outstanding saline-alkaline tolerance as a female parent and an upland cotton variety B with excellent fiber quality and good yield as a male parent, and performing hybridization to obtain F1-generation seeds; s2, early-stage multi-dimensional comprehensive screening: adopting a multi-stage screening system integrating genotype, phenotype and physiological indexes from F2 to F4 generations, and directionally selecting and polymerizing single plants with saline-alkaline tolerance and high-quality and high-yield potential. According to the breeding method of the saline-alkali-tolerant, high-quality and high-yield cotton variety, through organic combination of strategic parent selection and matching and a multi-dimensional early screening system, excellent genes can be directionally polymerized, and breakthrough varieties which are excellent in both saline-alkali soil and non-saline-alkali soil are stably bred.

This invention provides a method, apparatus, device, and medium for medical feature selection, relating to the field of medical data processing technology. It addresses the technical problem of insufficient accuracy in selecting optimal feature subsets. The method comprises: constructing an improved aurora optimization algorithm that includes an archive-driven population evolution strategy and a directional selection mechanism based on a reference feature subset. The former uses a search mode with the centroid of failed archives as the reference feature subset in the early stages of iteration, guiding the population away from the centroid of failed archives to avoid inferior feature regions; in the later stages of iteration, it uses a search mode with the centroid of successful archives as the reference feature subset, guiding the population to converge towards the centroid of successful archives. The latter constructs a directional update direction vector based on the difference between the reference feature subset selected by the archive-driven population evolution strategy and the current feature subset, guiding the directional update of the feature subset. This can select the optimal feature subset that better meets the data analysis needs of the target medical dataset.