SECTION 13 



PLANT GENETICS AND BREEDING 



13.1. Studies on the Interspecific Hybrid Lupinus 

 rothmaleri Klink. x lupinus luteus L. 



T. Kazimierski (Poznari, Poland). 



Lupinus rothmaleri possesses several qualities, 

 e.g. small-seedness, delicacy and others which it 

 would be very advisable to combine with the 

 properties of L. luteus. For this purpose attempts 

 were made to cross these two species. Hybrid 

 seed was obtained when L. rothmaleri was the 

 seed parent, and L. luteus the pollen parent. 

 Out of 174 L. rothmaleri flowers pollinated by 

 L. luteus 5 pods yielding 14 seeds were set. On 

 the other hand, out of 505 L. luteus flowers 

 pollinated by L. rothmaleri 134 pods were set but 

 they contained no well-developed seeds. 



Hybrids of the first generation possessed inter- 

 mediate morphological features and physiologi- 

 cal properties. They were in the blooming period 

 since April 20 to October 20, but set only 4, 

 i.e. 0.4 per cent one-seeded pods. 



Backcrossed hybrid flowers failed to produce 

 pods and shanked off after 12 to 20 days. Also 

 parent flowers mated with the hybrids wilted 

 after 10 to 14 days. 



Analyses of pollen viability performed in a 

 mixture of acetocarmine with glycerin revealed 

 around 20 per cent (19.6) of viable pollen in the 

 hybrids. Cytoembryological studies of hybrid 

 ovules proved that the sporogenesis and game- 

 togenesis were normal only in 1.8 per cent of 

 ovules; in the remaining ones macrospores and 

 embryo sacs disintegrated. The high sterility of 

 hybrids was mainly due to aberrations in the 

 processes of macrosporogenesis and macrogame- 

 togenesis. 



13.2. Meiosis in Triploid and Allotetraploid Hybrids 

 between Beta vulgaris L. and Species of the 

 Section Patellares Tran. in connection with 

 Transmission of Genes. Helen Savitsky 

 (Salinas, U.S.A.). 



Hybrids between B. vulgaris (sugarbeet) and 

 diseases-resistant Patellares species (B. patellaris 

 Moq., B. procumbens Chr. Sm., B. webbiana 

 Moq.) are usually inviable and sterile; viable 

 semi-fertile triploid and allotetraploid hybrids 



are obtained. Hybrids between B. vulgaris and 

 Patellares species are segmental hybrids. Sterile 

 diploid hybrids show to 5 bivalents (n=9). 

 Triploid and tetraploid hybrids form complex 

 associations. Triploids form tri- and quadri- 

 valents, while allotetraploids form quadrivalents, 

 pentavalents, hexavalents, and higher valency 

 associations. Configuration of some multivalents 

 and excess of chiasmata over the limits possible 

 for vulgaris-patellaris associations indicate the 

 occurrence of translocations and structural 

 changes of chromosomes. Each multivalent 

 association involves 1 or more chromosomes of 

 Patellares species, or translocated chromosomes 

 of parental species. First backcross generation 

 (Fi x B. vulgaris) resembles sugarbeet, but carries 

 some characters of wild species. Segments of 

 chromosomes and some chromosomes of Patel- 

 lares species (in trisome plants) are transferred 

 to bi generation. Outline of meiosis indicated 

 the possibility of genes* transmission in Vulgaris- 

 Patellares hybrids. 



13.3. The Allopolyploid Hybrid between Fragaria 

 vesca and F. moschata. J. R. Ellis (London, 

 Great Britain). 



Many attempts have been made to hybridize 

 the diploid Fragaria vesca with the hexaploid 

 F. moschata, the object being in most instances 

 to combine the everbearing habit of alpine forms 

 of F. vesca with the highly esteemed musk 

 flavoured fruit of F. moschata. A small number of 

 sterile hybrids have been reported and these have 

 been either tetraploids, pentaploids or hepta- 

 ploids, the latter two types having originated 

 from unreduced gametes in the diploid and 

 hexaploid species respectively. No hybrids have 

 as yet been reported to have originated through 

 non-reduction in both parents, an event which 

 would give rise directly to the allo-octoploid 

 hybrid. 



From a series of colchicine treatments and 

 hybridizations, a moderately fertile allo-octo- 

 ploid hybrid line has been established. Pentaploid 

 hybrids obtained from crosses between auto- 

 tetraploid F. vesca and F. moschata. were 

 colchicine-treated to give decaploid hybrids, 



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