Screening Of Excellent Hybrid Combinations Of Root Mustard And Study On The Genetic Rules Of Late Bolting Traits

Root mustard,or turnip,is a mustard vegetable in the Brassica genus of the Brassicaceae family.The root mustard studied in this experiment is a local specialty vegetable in Hubei,Xiangyang turnip,which is not suitable for raw consumption and is often used as salted vegetables.In this experiment,eight high generation kohlrabi inbred lines were selected as parents after multiple generations of self crossing separation by the research team.Combinations were made according to the complete diallel crossing method.Correlation analyses on the most important agronomic traits,yield traits and quality components of the F₁hybrid generation and the parents as well as heterosis analyses and grey correlation analyses on the most important traits were performed to provide a theoretical basis for the use of heterosis and the breeding of new kohlrabi varieties.In addition,the late twitch material was crossed with early twitch material to obtain F₁generation seeds.The F₁was self-crossed to obtain the F₂generation seeds to construct the F₂genetic segregation population.Simultaneously using parental and F₁materials for backcrossing,obtaining B₁and B₂backcrossing populations.Under natural cultivation in the field,the genetic performance of bolting traits in the G6 population of Chinese cabbage was investigated,and the genetic law of late bolting traits was preliminarily studied.The conclusions are as follows:1.Genetic variation in the main traits.In addition to plant height,plant width,leaf length and leaf width,the main traits such as total weight per plant and fresh weight per root showed significant differences of varying degrees,indicating that the material in this trial is rich in genetic diversity.The coefficients of genetic variation were higher for fresh weight,total weight,protein content,nitrate content and vitamin C content,reaching29.25%,27.64%,33.87%,25.11%and 22.60%respectively.2.Heterosis analysis.The main characters of kohlrabi were divided into agronomic characters,yield characters and quality characters for heterosis analysis.The results showed that heterosis could significantly improve the total weight per plant,fresh weight per root,yield per mu and other characters of offspring,greatly improve the yield of kohlrabi,and achieve the breeding goal of high yield.In addition,it also shows that heterosis can reduce plant height,plant width,leaf width and other traits.It improves the marketable appearance of turnips by reducing the growth potential of the above-ground portion and concentrating nutrients in the thicker,underground roots.3.Organoleptic evaluation of fresh dahlrabi.The hybrid combinations 8-5×19-3and 16-2×13-2 had the highest total score of 42.5（out of 60）,followed by 9-1×4-3,2-2×9-1 and 3-2×2-2,indicating that the fresh sensory quality of these hybrid combinations was the best.Taken together,the greater sweetness,lower bitterness and astringency,and higher crispness and retention of some mustard spiciness were more popular among the dasheen.The results also indirectly suggest that the hybrid advantage of dasheen improves its fresh eating taste.4.Grey correlation analysis.Using the correlation degree analysis method in grey system theory to conduct comprehensive fuzzy evaluation on 56 test combinations,the result closest to the reference variety is X₁₀（3-2×8-5）(R₁₀’=0.7338),followed by X₂₇（9-1×2-2）、X₂₆（8-5×19-3）、X₂₁（4-3×19-3）,indicating that these hybrid combinations of turnip have excellent comprehensive traits and are closest to the reference variety.5.Analysis of the Genetic Law of Late Bolting Traits.By constructing a G6population with late bolting traits and recording the bolting period data of each generation in the field,using the R software package SEA v2.0 and the plant quantitative trait analysis method,the optimal genetic model for the bolting trait of Chinese cabbage was analyzed as E-0（MX2-ADI-ADI）,which is 2 pairs of additive-dominant-supernatural primary genes+additive-dominant-supernatural polygenic inheritance model.