Comparative Analyses of Disease Resistant and Nonresistant Lines from Maize × Zea Diploperennis by GISH

Abstract

After a cross between maize inbred line Lu9 and Zea diploperennis (DP) and a backcross between their F1 and Lu9, the BC1 was reproduced with parthenogenesis induced by chemicals. In this study a2-① and a2-⑥, the two tested, stable alloplasmic sister lines, were obtained through selecting and selfing of the parthenogenetical progenies for over ten generations. The line a2-①showed DP characters, such as resistance to Helminthosporium turcium Pass, H. maydis Nisik, and H. carbonum ULL strup while a2-⑥ exhibited no such resistance. The introgressed DP DNA segments were successfully detected, and their physical location on chromosomes were compared in these two lines by genomic in situ hybridization (GISH). In line a2-①, the hybridization signals were located on the long arms of chromosomes 1, 2 and 8, and on the short arm of chromosome 6; in line a2-⑥, they were located only on the long arms of chromosomes 1, 2 and 8, with no signal on chromosome 6 at all. The distribution of introgressed DP segments on chromosomes, reasons for differences of disease resistance between these two lines, and the existence of resistance genes in the introgressed segments are discussed.