Professor Jaya Shankar Telangana State Agricultural University (PJTSAU), Rajendranagar, Hyderabad 500030, Telangana, India; and International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Hyderabad 502324, Telangana, India.
ICRISAT, Patancheru, India.
Plant Dis. 2018 Jun;102(6):1136-1140. doi: 10.1094/PDIS-07-17-0959-RE. Epub 2018 Apr 10.
Pearl millet downy mildew (DM), caused by Sclerospora graminicola, is of serious economic concern to pearl millet farmers in the major crop-growing areas of the world. To study the inheritance and allelic relationship among genes governing resistance to this disease, three DM-resistant pearl millet lines (834B, IP 18294-P1, and IP 18298-P1) and one susceptible line (81B) were selected on the basis of disease reaction under greenhouse conditions against two isolates of S. graminicola (Sg 526-1 and Sg 542-1). Three resistant parents were crossed with the susceptible parent to generate F, F, and backcross BCP (susceptible parent × F) and BCP (resistant parent × F) generations for inheritance study. To carry out a test for allelism, the three resistant parents were crossed with each other to generate F and F generations. The different generations of these crosses were screened for disease reaction against two isolates (Sg 526-1 and Sg 542-1) by artificial inoculation under greenhouse conditions. The segregation pattern of resistance in the F and corresponding backcross generations revealed that resistance to DM is controlled by a single dominant gene in 834B and IP 18294-P1 and by two dominant genes in IP 18298-P1. A test for allelism inferred that a single dominant gene for resistance in 834B is nonallelic to that which governs resistance in IP 18294-1, whereas one of the two dominant genes for DM resistance in IP 18298-P1 against the test isolates is allelic to the gene for DM resistance in 834B and a second gene is allelic to the resistance gene present in IP 18294-P1.
珍珠粟霜霉病（DM），由 Sclerospora graminicola 引起，是世界主要种植区珍珠粟种植者关注的严重经济问题。为了研究控制该疾病抗性的基因的遗传和等位关系，基于温室条件下对 S. graminicola 的两个分离物（Sg 526-1 和 Sg 542-1）的疾病反应，选择了三个抗 DM 的珍珠粟品系（834B、IP 18294-P1 和 IP 18298-P1）和一个敏感品系（81B）。三个抗性亲本与敏感亲本杂交，生成 F1、F2 和回交 BCP（敏感亲本×F1）和 BCP（抗性亲本×F1）世代，进行遗传研究。为了进行等位性测试，三个抗性亲本相互杂交，生成 F1 和 F2 世代。这些杂交的不同世代在温室条件下通过人工接种对两个分离物（Sg 526-1 和 Sg 542-1）进行疾病反应筛选。F1 和相应回交世代对 DM 的抗性分离模式表明，834B 和 IP 18294-P1 中的 DM 抗性由单个显性基因控制，而 IP 18298-P1 中的 DM 抗性由两个显性基因控制。等位性测试推断，834B 中抗性的单个显性基因与 IP 18294-1 中控制抗性的基因非等位，而 IP 18298-P1 中对测试分离物的 DM 抗性的两个显性基因之一与 834B 中的 DM 抗性基因等位，第二个基因与 IP 18294-P1 中存在的抗性基因等位。
