抗丝黑穗病、抗败育高粱A_2细胞质雄性不育系A_2Sx3197的选育

Development of Cytoplasmic Male Sterile Line A_2Sx3197 with Resistance to Head Smut (Sphacetheca reliana Clint) and Pollen Abortion in Sorghum vulara

A1Tx3197曾经是我国广泛应用的高粱细胞质雄性不育系,20世纪70年代末,由于高粱丝黑穗病病菌生理小种分化,该不育系以及用其配制的杂交种逐渐失去了对高粱丝黑穗病菌的抗性。同时该不育系小花败育日渐严重,制种产量极低,甚至造成绝收。为了改良A1Tx3197的抗病性及抗败育性,本研究利用A2保持系在A1位点含有A1育性恢复基因MS1MS1和在A1细胞质背景下表现恢复的特点,以不育系A1Tx3197为轮回亲本,以含有抗丝黑穗病、抗败育基因的BV4为供体,通过杂交和多代回交,得到含有双抗基因的A2类型细胞质雄性不育的保持系BSx3197(MS1ms1ms2ms2),在该材料自交的同时,用其对A2细胞质雄性不育系进行细胞核代换,经过多代回交和自交,最终育成了抗丝黑穗病、抗败育的A2细胞质雄性不育系A2Sx3197和保持系BSx3197(MS1MS1ms2ms2)。结果表明,新选育的不育系A2Sx3197在A1和A5细胞质背景下表现恢复,在A2、A3、A4、A6和9E细胞质背景下表现不育,丝黑穗平均发病率为0～0.8%,败育率为0～8.4%,抗丝黑穗病性、抗败育性明显优于被改良不育系,接近或达到抗源供体BV4水平;而在抽穗期、株高、穗长、穗宽、千粒重、穗粒重、粒色、壳色、穗形、穗型等主要性状方面与A1Tx3197差异不显著。

The sorghum cytoplasmic male sterile （CMS） line A1Tx3197 was used widely in China. At the end of 1970s, this line and its hybrids gradually lost resistance to sorghum head smut because of race shift. Meanwhile, the floret abortion of this line led to low yield. Since the maintainer of A2 type CMS can restore the fertility of A1 type CMS, to improve the head smut resistance and floret fertility of A1Tx3197, BV4 with the genes conferring the head smut and floret abortion resistances was used as a donor, and A1Tx3197 was used as a recurrent parent. After five generation backcrossing, an intermediate material BSx3197 carrying head smut and floret abortion resistance genes, a maintainer for A2-CMS, was acquired. Then BSx3197 was used to replace the karyon of A2 type CMS line. Finally, a novel A2 type CMS line AaSx3197 with its maintainer BSx3197 （MS1MS1m2ms2） was bred. The line A2Sx3197 was restorable in Al and As cytoplasmic background, but sterile in A2, A3, A4, A6, 9E cytoplasmic background. The average disease incidence of A2Sx3197 was 0-0.8%, and the average abortion incidence was 0-8.4%. AESX3197 had significantly higher resistance to the head smut and floret abortion than A1Sx3197, which was similar with BV4. The main agronomic traits of AESX3197 and A1Tx3197 were not significantly different, such as days of heading, plant height, spike length, spike width, 1000-grain weight, grain weight per spike, grain color, shell color, spike shape, and spike type.