芥菜抗蕪菁嵌紋病毒與同功異構酶伴連之研究

Associated Analysis of Isozymes and Turnip Mosaic Virus (TuMV) Resistance in Mustard (Brassica juncea (L.) Czerniak.)

以抗蕪菁嵌紋病毒（TuMV）的苗栗芥菜（R型）和感病的新竹、竹北芥菜（S型）進行七種酵素比較分析；三品種間GOT酵素個體間條帶型均一致沒有差異，其酶圖呈單態型。SkDH和PRX在抗病品系（R）與感病品系（S） 有一處不一樣的條帶型，而ACP-α-5群有二處相異的條帶型。後裔檢定以抗病品系（苗栗）感病品系（竹北）的雜交F₁及F₂代族群，分析ACP，PRX和SkDH之變異性，在雜交F₁代各個體中三種酵素表現型（F₁型）皆很一致，具表現兩親本型的共顯性現象。F₂子代在差異區ACP-α-5F、ACP- α-5S、SkDH-1及PRX-1的分離顯示這些異型酶為單元體，由後裔分析，知四個相異區為單一因子遺傳；其基因座分別命名為Acp-α-5F、Acp-α-5S、Skdh-1和prx-l，可提供作為遺傳指標。兩參試品系經接種調查F₁、F₂代之發病情形，並分析病徵與四個酵素基因表現型之關係；F₁代大都均呈現抗、耐病性，顯示抗病性有顯性基因參予；F₂分離族群依病徵分四群：無病徵（抗病）、脈透明化（耐病）、嵌紋狀（感病）和嚴重嵌紋狀（嚴重感病），並分析ACP-α，PRX和SkDH的表現型顯示ACP-α-F，ACP-α-S，SkDH-1和抗病性無相關性，而PRX-1之抗病型（R型），出現40%的抗病株和55%的耐病株，初步顯示，PRX-1和抗病性有關。Prx-l和抗病基因有伴連作用。

The inheritance of ACP- α, GOT, PRX and SkDH isozymes between 'Chu -Pei', 'Shin-Chu' (susceptible ot TuMV) and 'Miau-Li' (resistant to TuMV) mustard were analyzed through progeny testing. Monomorphism of GOT phenotype in three mustards were detected. Since 'Chu-Pei' and 'Shin-Chu' have same band pattern of four isozymes, the progeny test only involved two varieties (Miau- Li and Chu-Pei). The F₁ from of ACP- α, PRX and SkDH were characterized by the codominance expression of parental types. Two Parental types were recovered in F₂ population. The segregation of phenotypes fit a 3 : 1 ratio, demonstrating a monofactor inheritance. It is suggested that null allele of PRX-1 was existing in 'Miau-Li' (R type), and that of ACP- α -5S and SkDH-1 in 'Chu-pei' (S type) mustard. Three isozymes are tentatively assigned to be controlled by Acp- α -5F, Acp- α -5S, Prx-l and Skdh-1 loci respectively. The result to TuMV was evaluated in 'Miau-Li', 'Chu-Pei' and their progenies by inoculated test and it is relationship with 4 loci were also analysed. Resistance seem to be specified by dominant genes throug F₁ generation expression. In F₂'s judged were by divided into 4 groups including symptomless(resistant), vein clearing (tolerant), mosaic (susceptible) and severe mosaic (serious susceptible). Analysis result from phenotypes of 4 isozymes loci indicated the relationship of resistance (or tolerance) with PRX -1 only. More than 95% of PRX-1 'R type' was detected in F₂ population. It is postalated that Prx-l loci is association TuMV resistant gene, can be used as genetic marker for TuMV reistance.