Occurrence and genetic identity of male sterility-inducing cytoplasm in rye (Secale spp.).

Mirosław Łapiński

Department of Plant Breeding, Agricultural University, Słowackiego 17, 71-434 Szczecin, Poland (Poland)

Stefan Stojałowski

Department of Plant Breeding, Agricultural University, Słowackiego 17, 71-434 Szczecin, Poland (Poland)

Abstract

Individual plants of 50 open-pollinated cultivars originated from 23 world-wide countries, 18 inbred lines and 9 wilde species and/or subspecies of rye were tested for the presence of sterility-inducing vs. normal cytoplasm, using conventional plasmotype/genotype interaction test. One  to fourteen random plants from each population were crossed as females to inbred lines representing nonrestorer genotype in both, Pampa and Vavilovii, types of sterility-inducing cytoplasm. The F₁  and Bc₁ or F₂ progenies were scored for male fertility/sterility expression. The results showed that male sterility-inducing cytoplasm was common in the sample of a  world-wide rye population. Out of a total 629 single plants tested, 366 plants had sterility-inducing cytoplasm and all of them were derivatives of a cultivated rye populations. Among 50 cultivars and local populations of cultivated rye either normal or sterilizing cytoplasm was found in 9 and 19 populations, respectively, while 22 populations consisted of both plant types, with normal and sterilizing cytoplasm. A random sample of 61 male sterile Bc₂ - Bc₃ single plant progenies (a new sources of cms) developed from 28 populations were crossed to the L1 inbred line, acting as nonrestorer in Pampa and as restorer in Vavilovii cytoplasm, in an attempt to identify the type of sterility-inducing cytoplasm detected. Fifty of the 61 F₁ progenies were male fertile indicating the presence of Vavilovii cytoplasm. Eleven F₁ progenies were either male sterile or segregating but  backcrossing of male sterile segregates resulted in male sterile Bc₁ and Bc₂ progenies, thus  indicating that they all had Pampa cytoplasm. These progenies originated from plants of 6 South-American populations.