小麦-簇毛麦端体附加系中6V端体的细胞遗传学行为及其在Moisson 6M^v/6B中的传递

Transmission of Chromosome 6V Telomere Through Gametes in Moisson 6M^v/6B and Cytogenetic Behaviour of 6VS in Wheat-D D.Villosum Telosomic Addition Line

簇毛麦6V染色体上携有抗白粉病基因Pm21.本研究利用抗白粉病小麦-簇毛麦单端体和双端体附加系(2n=42+1t和2n=42+2t)为材料,通过自交,观察后代植株6V端体出现频率,以评价外源染色体在小麦背景中的遗传平衡程度及稳定性,为利用培育小麦-簇毛麦导入系提供理论依据.通过对自交群体植株根尖细胞染色体数观察,发现在双端体附加系(2n=42+2t)自交群体(F2)中,2n=42+2t,2n=42+1t,2n=42的出现频率分别为51.92%,40.38%和7.7%;在单端体附加系(2n=42+1t)的F2群体中,2n=42+2t,2n=42+1t,2n=42的出现频率分别为1.85%,17.59%和80.56%.χ2检验表明(χ20.01=0.000),两自交群体间6V端体传递能力存在显著差异,6V端体的传递能力与亲本携带的端体数密切相关,双端体附加系在减数分裂时主要形成n+t配子,而单端体附加系则形成n和n+t两种配子,n+t配子参与受精的竞争能力主要取决于6V端体的遗传平衡程度,单端体附加系自交群体中的6V端体出现频率较低.这表明6V端体可能携有较多的不利基因导致n+t配子竞争能力较差.小麦-簇毛麦6V双端体附加系Pana(2n=42+2t)6VS在Moisson 6Mv/6B中通过雌雄配子传递频率研究发现,6VS通过雌配子的传递频率(33.33%)远高于通过雄配子的传递频率(4.87%).这也与其抗病性鉴定结果一致.此外,还发现以Pana(2n=42+2t)为母本获得了小麦-偏凸山羊草-簇毛麦三属杂种,而以Pana(2n=42+2t)为父本却未能获得小麦-偏凸山羊草-簇毛麦三属杂种,暗示Pana(2n=42+2t)附加端体可能对花粉育性有一定不利影响.

Chromosome 6V of D. Villosum carrys powdery mildew resistant gene Pm21. The monotelocentric addition line and ditelosomic addition line （2n =42 ＋ 1t and 2n = 42 ＋ 2t） were inbreded and we observed the occurrence frequency of 6V telomere to evaluate the genetic equilibrium level and stability of alien chromosome in the genetic background of common wheat, which would provide theoretical basis for the utilization and creation of Wheat - D. Villosum introgression line. The result of cytological observations of root-tips showed, in the inbreeding population （ F2 ） of ditelosomic addition line （2n = 42 ＋ 2t）, the occurence frequencies of 2n = 42 ＋ 2t,2n = 42 ＋ 1 t,2n = 42 were 51.92% ,40.38 % and 7.7% respectively; in the F2 population of mono -telocentric addition line （2n =42 ＋ 1t）, the occurence frequencies of 2n =42 ＋ 2t,2n =42 ＋ 1t,2n =42 were 1.85% ,17.59% and 80.56%. χ^2 test showed there was singnificant difference of transimission ability of 6V telomere between the two inbreeding populations, which indicated the transmission rate of telomere was related to the number of telomere carried by parents. Ditelosomic addition line mainly formed n ＋ t gametes in meiosis, while mono - telocentric addition line forms two gamete types, n and n ＋ 1. The ability for fertilisation of n ＋ 1 gametes depended on the genetic equilibrium level of 6V telomere. , and the 6V telomere occurence frequency in inbreeding population of mono - telocentric ad- dition line was lower, which indicated the competition power of n ＋ 1 gametes was lower for 6V telomere carrying some unfavorable genes probably. The results of study on the transimission rate of 6VS through male and female gametes of Wheat-D. Villosum 6V ditelosomic addition line of Pana（2n =42 ＋2t）in the genetic background of Moisson 6M^V/6B showed, the transmission rate of 6VS through female gametes （33.33%） was significantly higher than that （4.87%） through male gametes. This result was concordant with the result of disease resistance. Additionally, we obtained three genera of Wheat - Ae. Ventrieosa - D. Viliosum based on the utilization of Pana as female parent, while failed to obtain the three genera based on the utilization of Pana as male parent. This result implied that telomere in Pana（2n = 42 ＋ 2t）might have negetive effect on fertility of pollen.