Section 13 — Plant Genetics and Breeding 



breeding methods (hybridization, selection, 

 training on high-fertile soil, etc.) many sugar beet 

 varieties have been developed and are grown in 

 the U.S.S.R.: Uladovskaya 752, Verkhnjachs- 

 kaya 031, Verkhnjachskaya 038, Ivanovskaya 

 1745, Lgovskaya 059, Ramonskaya 06, Ramons- 

 kaya 023, Ramonskaya 065, Bijskaya 032, Kir- 

 ghizskaya 056, Pervomaiskaya 028, Mezhotnens- 

 kaya 080, and others. Home varieties of mono- 

 germ sugar beet are sown on the vast territory. 

 They are: Byelotserkovskaya Odnosemyannaya 

 1, Yaltushkovskaya Odnosemyannaya 2, Kir- 

 ghizskaya Odnosemyannaya 8. A number of 

 monogerm varieties are under State Variety Trials. 



In conditions of intensive development of the 

 U.S.S.R. sugar beet growing, the development 

 and introduction of varieties and hybrids 

 (including monogerm) and the use of heterosis 

 in the first generation is of prime importance. 



Together with developing of diploid varie- 

 ties and hybrids, the development of polyloid 

 varieties is of great interest, the latter including 

 a large number of triploid hybrids. 



A large number of polyploid varieties developed 

 in the U.S.S.R. are under variety trials and in 

 the near future they will be released. 



According to the data of the State Variety 

 Trials the best monogerm triploid hybrid 

 obtained at Byelotserkovskaya Breeding Station 

 in 1962 overcame the diploid monogerm variety 

 of this Station for sugar yield by 3.7-7.9 centners 

 per hectare in different localities. 



To increase the productiveness of polyploid 

 varieties we conduct a serious task on the 

 development and use of male sterility in the 

 process of breeding and seed growing. 



In order to reproduce and stabilize sterility 

 zero-pollinators are selected, inzucht (inbreed- 

 ing) reproduction being accompanied with 

 regular culling of half-sterile and fertile forms. 



The best hybrids developed on the ground of 

 sterility will be used in production in the nearest 

 future. 



(under single irradiation) is a dose of 7-8kr 

 and with such a dose only 9-25 per cent of 

 irradiated plants survive. Under irradiation of 

 seeds with a dose of lOkr the germination power 

 was 80-90 per cent, while the germination power 

 of the control seeds was 60-70 per cent. 



Most seedlings having grown from irradiated 

 seeds began to flower much earlier than the 

 control seedlings. Thus in the control two 

 years after sowing, 30-50 per cent of the seedlings 

 flowered, while the percentage of flowering in 

 the irradiated seedlings was 75-85 per cent. 



It was observed also that genetic variability in 

 irradiated seedlings was greater than in the 

 control. 



In colouring of flowers in the control it could 

 be observed that the colour of flowers of the 

 paternal and maternal type oi of one of them 

 inherited most often (for example, domination of 

 deep-red colour). Irradiated seedlings (the dose 

 0.5-2kr) in the first generation (Yt) showed 

 great diversity in colour and shape of flowers 

 (up to 5-6 groups). Amoug irradiated seedlings 

 was observed the appearance of shortish and 

 dwarfish forms. 



The diversity of irradiated seedlings in hybrids 

 obtained from geographically remote forms was 

 especially great. 



Among the seedlings having grown from 

 irradiated seeds, I, together with G. E. Kazari- 

 nov, selected much more interesting seedlings 

 from the point of their ornamental perspective 

 than among the control hybrids. 



In 1962 we selected for further research and 

 studies, 140 seedlings valuable for their colour 

 and corrugated, fringed and crocus-like flowers. 



(!) kr=1000 roentgen. 



13.80. Induced Mutants and Their Suitability to 

 Hybridization Breeding in Barley. Friedrich 

 Scholz (Gatersleben, DDR). 



13.79. Influence of Ionizing Radiation on Genetic 

 Variability of Gladiolus Seedlings. IV. Drya- 

 gina (Moscow, U.S.S.R.). 



Hybrid seeds of fifteen varieties of the gladio- 

 lus varying not only in color and shape of 

 flowers but in geographical origin were exposed 

 to radiation. 



Dry seeds were exposed to Co 60 before sowing. 



The doses: 0.5,2,5, and lOkr 0)were tested. 

 Experiments showed that gladiolus seeds are 

 more radiation-resistant than their bulbo-tubers. 



The critical dose for gladiolus bulbo-tubers 



Experimental induction of gene mutations is a 

 promising tool in plant breeding, particularly for 

 specific improvements, e.g. as to lodging resist- 

 ance, early maturing, and the like. No lengthy 

 backcross procedure is necessary as unavoidable 

 if non-adapted material is used as source of a 

 desired character. The induced mutants are 

 especially suitable to hybridization breeding. 

 By crosses between various mutants many new 

 combinations of characters can be produced. 

 Thus several breeding objectives may be realized 

 simultaneously. 



Model experiments were performed in con- 



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