GENETIC DIFFERENTIATION IN WHEAT NUCLEAR GENOMES IN RELATION TO COMPATIBILITY WITH Title AEGILOPS SQUARROSA CYTOPLASM AND APPLICATION TO PHYLOGENY OF POLYPLOID WHEATS Author(s) OHTSUKA, Ichiro Citation Journal of the Faculty of Agriculture, Hokkaido University, 65(2), 127-198 Issue Date 1991-10 Doc URL http://hdl.handle.net/2115/13113 Type bulletin (article) File Information 65(2)_p127-198.pdf Instructions for use Hokkaido University Collection of Scholarly and Academic Papers : HUSCAP J. Fac. Agr. Hokkaido Univ., Vol. 65, Pt. 2 : 127-198 (1991) GENETIC DIFFERENTIATION IN WHEAT NUCLEAR GENOMES IN RELATION TO COMPATIBILITY WITH AEGILOPS SQUARROSA CYTOPLASM AND APPLICATION TO PHYLOGENY OF POLYPLOID WHEATS Ichiro OHTSUKA * Doctoral thesis, Faculty of Agriculture Hokkaido University, Sapporo 060, Japan (Received December 27, 1990) CONTENTS INTRODUCTION ..................................................................................................... '129 CHAPTER I. Compatible relation between wheat nuclear genomes and Aegilops squarrosa cytoplasm Introduction··························································.············· ... ········ ......... ·132 Materials and Methods ........................................................................... 132 Results and Discussion .. · .........: ................................................................ ·135 1. The alloplasmic lines with squarrosa cytoplasm and their fertility a) Alloplasmic lines of Dinkel wheat ...................................................... 135 b) Alloplasmic lines of Emmer wheat ...................................................... 136 c) Alloplasmic lines of Timopheevi wheat ................................................ 139 2. Selective transmission of an additional chromosome (dx) in the alloplasmic lines of Em~er wheat with squarrosa cytoplasm a) Zygotic lethality caused by the absence of dx chromosome ...... · ...... · .... 140 b) Gametophytic sterility in pollen grains without dx chromosome .......... "143 c) Selective transmission of dx chromosome indispensable for the compatibility with squarrosa cytoplasm ......................................... '145 3. Identification of dx chromosome responsible for the compatibility with squarrosa cytoplasm a) Function of dx chromosome in the compatibility of AB genome with squarrosa cytoplasm ........................................... "146 b) Monosomic·iD·trisomic·iA or ·iB series in the alloplasmic lines of Dinkel wheat with squarrosa cytoplasm .............. · .. · ...... · .......... ·147 c) Gametophytic sterility and zygotic lethality in the monosomic·iD-trisomic-iA or -iB series of Dinkel wheat with squarrosa cytoplasm ............................................ '148 CHAPTER II. Genetic analysis of the compatible relation between tetraploid wheat genomes and Aegilops squarrosa cytoplasm * Present address: Laboratory of Biology, Kanagawa University, Yokohama 221, Japan. 128 1. OHTSUKA Introduction···························································································· ·152 Materials and Methods .......................................................................... ·152 Results and Discussion 1. Zygotic lethality due to the combination of tetraploid wheat genomes and squarrosa cytoplasm a) Different responses of AABB and AAGG genome species in crossing experiments to (squarrosa) AABB+ lD lines························153 b) Abnormality of Fl seeds in crosses to (squarrosa) AABB+ lD lines with various tetraploid wheat species ............................................... ·155 2. Chlorophyll variegation and plant weakness caused by the interaction between tetraploid wheat genomes and squarrosa cytoplasm a) Development of Fl seedlings in the crosses to (squarrosa) AABB+ lD lines ............................................... ·············159 b) Chlorophyll variegation in the Fl miniature plant ·································162 c) Segregation of plant type in B1F 1 lines··············································· ·162 3. Genetic differentiation of the cytoplasm compatibility in tetraploid wheat species································································· ·166 CHAPTER III. Phylogenie relationships of polyploid wheat species based on responses to Aegilops squarrosa cytoplasm Introduction···························································································· ·168 Materials and Methods .......................................................................... ·168 Results and Discussion 1. Classification of tetraploid wheat strains based on response to squarrosa cytoplasm a) Response types in relation to genomic compatibility with squarrosa cytoplasm ................................................................. ·169 b) Classification of 104 strains of tetraploid wheat species on the basis of compatibility response to squarrosa cytoplasm appearing in Fl seeds and seedlings ···················································170 2. Identification of response types of AABB genome involved in Dinkel wheat strains on the basis of compatibility with squarrosa cytoplasm a) Breeding of (squarrosa) AABBD pentaploid hybrids with various Dinkel wheat strains ...................................................... 176 b) B1FI seeds in crosses to (squarrosa) pentaploid hybrids ........... ·············179 c) B1FI plant types in crosses to (squarrosa) pentaploid hybrids ··················182 d) Experiment with (squarrosa) mono-trisomic lines of T. aestivum cv. Chinese Spring ........................................................ ·184 e) Classification of Dinkel wheat strains on the basis of compatibility of their AABB genome with squarrosa cytoplasm ........... ·184 3. Evolutionary pathway of polyploid wheat species based on the genetie differentiation of cytoplasm compatibility a) Genetic differentiation in tetraploid wheat species ............................. ·185 b) Polyphyletic origin of cultivated Emmer wheat and diphyletic origin of Dinkel wheat ............................................... ·186 WHEAT GENOME COMPATIBILITY TO AE. SQUARROSA CYTOPLASM 129 SUMMARy .............................................................................................................. '189 ACKNOWLEDGEMENTS ...................................................... ····································191 LITERATURE CITED ............................................................................................ ·192 INTRODUCTION (Historical Review) Phylogenetic classification of the species of wheat (genus Triticum) was first carried out by SCHULZ94 ). The genus was divided into three groups, i. e. Einkorn wheat (Einkorn-Reihe), Emmer wheat (Emmer-Reihe), and Dinkel wheat (Dinkel-Reihe) based mainly on morphological features. It was disclosed by SAKAMURA90) and SAX91 ) that the three groups consisted of diploid, tetraploid, and hexaploid species, whose haploid chromosome numbers are 7, 14, and 21, respectively, as demonstrates in the extensive cytological study carried out by KIHARA 20 ). It was also found that the three groups are series of allopolyploids with AA, AABB, and AABBDD genomes, respectively, through the study on triploid and pentaploid hybrids using various combinations among the three groups21). Genome analysis was used to study the phylogenetic relationships among wheats22), with not only the genus Triticum, but also the genus Aegilops, which consists of wild relatives of wheat. Based on the results of extensive studies conducted by KIHARA and his co_investigators23.26.29.33.4o.41.42.44.45.47.56.57), it was dis- closed that ten kinds of genomes (basic genomes) had been differentiated for the diploid species, including Einkorn wheat with the AA genome, and that allopoly­ ploid species (tetraploids and hexaploids) had evolved from the various combina­ tions of the basic genome species. It was thought that nine diploid species of the genus Aegilops and Einkorn wheat species (diploid wheat) had differentiated from a common ancestor (U genome species), based on similarities at various levels among the ten basic genomes24 ). Homoeologous relationships among the seven pairs of chromosomes in each genome were partially confirmed by SEARS95.96.97.98), based on the compensation ability among the chromosomes in the A, B, and D genomes of Dinkel wheat. Since SCHULZ'S taxonomical study, many explorations for wheats and their wild relatives have been carried out in relation to the origin of cultivated wheats and their areas of origin5.14.48.92.117.122). Because it was disclosed that T. timopheevi, discovered by ZHUKOVSKyI22) in Transcaucasia and initially regarded as an endemic species of Emmer wheat, did not have the AABB genome like Emmer wheat but had the AAGG genome, based on the genome analysis by LILIENFELD and KIHARA56), Timopheevi wheat (Timopheevi-Reihe) was added to SCHULZ's three groups. It was disclosed that the A genome, which is common to the four groups of 130 I.OHTSUKA genus Triticum, and the B genome of Emmer and Dinkel wheats are closely related to the S genome of Ae. speltoides, which belongs to the section Sitopsis in the genus Aegilops4I). It was also observed that the G genome of Timopheevi wheat is related to the S genome49). It was suggested that the D genome, which 27 72 is the third genome of Dinkel wheat, was derived directly from Ae. squarrosa • 1, as had since been proven experimentally43.73). BOWDEN!) proposed that all the species of the genus Aegilops should be included in the genus Triticum, because it is unlikely