Development of cytoplasmic male sterile (CMS) and maintainer (O-type) lines for resistance to bolting in sugar beet.
2007
Sadeqiyan, Yaqub | Sharifi, Hamid | Habib Khodai, A`li | Ebrahimiyan, Hamid | Ourazi Zadeh, Mohammad Reza | Ranji, Zabih Ol-Lah | Ahmadi, Mas`ud | Baqa`i Kiya, Mahdi | Moharram Zadeh, Majid | Vahedi, Sa`id | A`bd Ol-Lahiyan Nughabi, Mohammad | Basati, Jahan Shah | Aqa`i, Zadeh, Mohsen | Ebrahimi Kula`i, Hassan | Fotuhi, Keyvan | Bazr Afshan, Mohsen | Dehqan Sho`ar, Majid | Fathi, Mohammad Reza | Kuhestani, Manuchehr | Dast Jerdi, Vali Ol-Lah | A`ziz Pur, Mohammad Hossein | Nirumand Jahromi, Mohammad | Khoda Dadi, Shahram | A`rab Zadeh, Morteza | A`rab Salmani, Fatemeh
Sugar beet hybrid varieties are mainly improved on the basis of a genetic-cytoplasmic male sterile parent. Genes controlling Male sterility (aa) and self fertility (Sf) were applied to obtain a female male sterile line. In this study, two multigerm elites named 276 and 428 were crossed to the male sterile plants (SfSfaammxxzz) within an O-type in the greenhouse in 1994. In the first generation, four different genotypes were obtained where one designated with the Sf.AaxxzzMm…For the identification of maintainer genotypes all plants of four genotypes were crossed to CMS and AMS plants. Identified maintainers were back crossed to the primary male sterile plants in order to increase the frequency of maintainers in the next generations. Anyhow, 25% of resulted genotypes recognized as male sterile and 25% as monogerm maintainers. All plants of back crosses were in the field planted in separate rows with CMS lines. CMS and ms plants were allowed to receive pollen from the fertile plants and individual male sterile plants (msms) within the maintainer were harvested as S1 families. Half of the seeds of individual plants were contributed in the schteckling and half were evaluated for resistance to bolting and Cercospora leaf spot. Selected S1 families were checked for O-types through controlling their CMS counterparts. However, the first evaluation of S1 families was carried out at Dezful station in winter 1995. In parallel, BC1 to BC4 families were continuously improved till 1998. In summer 1997, superior BC3&lsquos were obtained and immediately contributed for the development of single crosses for saving time. The hybrids and their parents were examined in the greenhouse and field in 1997 and 1998. Triploid and diploid hybrids were developed in 1999. Examination of triploids was carried out in 1999 and 2000 in order to accelerate the release of commercial hybrids. In 2001, four diploid hybrids named 276, 191, 428 and 436 were released. The first triploid hybrids were commercialized in 2000 with the names of 261 and 7112. Improvement of new CMS lines were continued till 2005 and consequently more than 100 monogerm and 35 multigerm CMS lines have already been developed or under developing. Genetic materials obtained in this project are being evaluated in new projects. However single crosses with high combining abilities resulted from this project were 261x231, 436x231, 436x261, 436x7112, 428x231, 428x419, 428x474, 428x452, 7112x452, 436x452, 419x474, 7112x261, 428x7112, 428x261, 261x452, 436x231, 428x474, 7579x261, 7173x7112 and 7579x428. Indeed, new lines were originated from progenies of 7112, 419, 474 and 452 that showed high bolting resistance and some combined for improving new single crosses.
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