Rice blast is one of the most serious diseases in rice (Oryza sativa L.) worldwide. Jin 23B is the maintainer line, a parent for a number of hybrid rice varieties used widely in China. However, Jin 23B is highly susceptible to rice blast. In this study, Pi1, Pi2, and D12 were introgressed to improve the blast resistance of Jin 23B and its derived hybrids, Jinyou 402 and Jinyou 207, by marker-assisted selection (MAS). The improved Jin 23B, which carried single, two, and three genes, were evaluated for their resistance to rice blast using natural inoculation methods in disease nursery of Xianfeng, Hubei, China. The results showed that, the greater the number of genes contained in the improved Jin 23B and hybrids, the higher the resistance to rice blast. Pi1, Pi2, and D12 showed a strong dosage effect on the resistance to blast in the hybrid background during the entire growth duration in the field condition, being very useful for breeding blast-resistant hybrids. The result of examining agronomic traits showed that the improved Jin 23B and its derived hybrid rice were taller than or similar to controls, when there was no disease stress.
稻瘟病是世界范圍的最嚴(yán)重水稻病害之一。在中國，金23B作為保持系，是選育眾多雜交稻品種時廣泛使用的一個親本，但它非常易受稻瘟病侵染。在我們的研究中，通過標(biāo)記輔助選擇（MAS）的方法，將基因Pi1, Pi2, 和D12 導(dǎo)入到金23B及其衍生的雜交稻金優(yōu)402和金優(yōu)207中。然后將改良后的攜帶這其中1個、2個或者3個基因的金23B植株用自然接種的方法在中國湖北咸豐縣的病圃進(jìn)行稻瘟病抗性的評估。結(jié)果表明金23B及其雜交水稻中所包含的抗性基因越多，則其對稻瘟病的抗性越強。在大田條件下，雜交植株內(nèi)的Pi1, Pi2 和D12基因在植株的整個生育期中顯示出了強烈的對稻瘟病抗性的劑量效應(yīng)，這對于培育抗稻瘟病的雜交水稻是十分有用的信息。農(nóng)藝性狀的檢測表明了改良后的金23B及其衍生的雜交水稻植株在沒有疾病脅迫的情況下比控制組要高一些或者差不多。