| Production of male-sterile and restoration lines of
Pakistani wheat varieties with Ae. ovata and T. timopheevi
cytoplasms1) Chaudhry M. TAHIR Laboratory of Genetics, Faculty of Agriculture, Kyoto University, Kyoto, Japan A new chapter in wheat breeding was opened with the discovery of cytoplasmic malesterility (KIHARA 1951) ; in almost all the progressive countries, work to develop hybrid wheat was started vigorously by establishing male sterile and their counterpart restoration lines of commercial varieties. The present work of nucleus substitution to produce male sterile and their counterpart restoration lines of Pakistani wheat varieties with Ae. ovata and T. timopheevi cytoplasms was initiated in 1966, and the first crosses were practised in the spring of 1967 by using the following four nucleus substitution lines having Ae. ovata or T. timopheevi cytoplasm, as female parents : I. (ovata)-Norin 26 : Male-sterile line. II. (ovata)-P168 : Fertility restorer line. III. (timopheevi) -Bison : Male-sterile line. IV. (timopheevi) T. spelta duhamelianum : Fertility restorer line. In the start five T. aestivum varieties, namely, C273, C271, C591, C518, and Mexi- Pak 65 and one strain of T. sphaerococcum, Pak Kohni, were used as pollinators to the above-mentioned nucleus substitution lines, and in the later years five more varieties of T. aestivum, i.e., C228, AU49, AU44, Dirk and H-68 were included in the project. To accomplish the nucleus substitution work on accelerated pace two crops every year were raised, i.e., a greenhouse crop in winter (begining of September-middle of January) and a field crop in spring (end of January-middle of June). Every time the pollinators were grown in four repeats at one week interval to ensure the availability of pollen at the time of flowering for making subsequent backcrosses. Only, completely male sterile plants were utilized to develop sterile lines, and the plants exhibiting maximum pollen fertility were employed to establish restorer lines. |
| 1) The work has been supported by a scholarship from the Ministry of Education, Japan. |
| --> Next |