Improving Blast Resistance of a Thermo-Sensitive Genic Male Sterile Rice Line GD-8S by Molecular Marker-Assisted Selection

The broad-spectrum blast resistance gene Pi-1, from donor line BL122, was introduced into a thermo-sensitive genic male sterile rice line GD-8S, which possessed good grain quality but high susceptibility to rice blast, by using backcross breeding and molecular marker-assisted selection. Five elite improved male sterile lines, RGD8S-1, RGD8S-2, RGD8S-3, RGD8S-4 and RGD8S-5, were selected based on the results of molecular marker analysis, spikelet sterility, recovery rate of genetic background and agronomic traits. Thirty-three representative blast isolates collected from Guangdong Province, China were used to inoculate the improved lines and the original line GD-8S artificially. The resistance frequencies of the improved lines ranged from 76.47% to 100%, much higher than that of the original line GD-8S （9.09%）. On the agronomic characters, there were no significant differences between the improved lines and GD-8S except for flag leaf length and panicle number per plant. The improved lines could be used for breeding hybrid rice with high blast resistance.

Inheritance of the Male Sterility in a New Photo/Thermo-Sensitive Genie Male Sterile Line B06S of Rice

The major male sterile genes in a new photo/thermo-sensitive genie male sterile (PTGMS) line B06S of rice were analyzed by the manipulation of mixture distribution theory. The results indicated that a pair of major male sterile nuclear genes with large effects were responsible for controlling the male sterility of B06S.

Selection of Submergence Tolerant Homozygous Line by STS Marker and Twice Submergence Stress

One sequence tagged site marker Subl-1 and twice submergence stress method were used in selection of submergence tolerant homozygous line from Sub-lBS, a submergence tolerant, bentazon sensitive and photoperiod-sensitive and/or thermo-sensitive genic male sterile line that developed by our laboratory. The results revealed that the original Sub-lBS was heterozygous in SublA-1 locus even though it was identical in almost all of agronomical traits and the segregation of SublA-1 was in accordance with Mendelian law based on chi-square test. And then the original Sub-IBS was divided into two groups： one was ofSublA-1 introgression and the other was not; and the two groups were tested by twice submergence stress method. After the first submergence stress that lasted for 12 d, the average plant heights were significant difference at the 1% level between the two groups. After recovery for 10 d, the second submergence stress sustained for 18 d was carried on; and the group with SublA-1 gene was found apparently tolerant than the other group in submergence tolerance.

分子标记辅助选择培育抗稻瘟病杂交籼稻新品种扬两优316

以生产上广泛使用的光温敏感型核不育系广占63-2S为受体亲本,通过分子标记辅助选择,将广谱抗稻瘟病基因Pigm导入广占63-2S,育成新的抗稻瘟病光温敏感型核不育系扬籼3S,其除了具有广占63-2S开花习性好、配合力强的特点外,稻瘟病抗性明显提高,达到抗苗瘟、穗瘟病级1级的抗性水平。以扬籼3S为母本,以粒重高、品质优、配合力好、抗倒性强的恢复系扬恢916为父本,配组选育成两系杂交中籼新组合扬两优316,因其产量高、优质、抗稻瘟病、抗倒,2017年通过江苏省审定。此外,对利用分子标记辅助选择培育抗稻瘟病品种的策略进行了探讨。