Section 13 — Plant Genetics and Breeding 



13.85. Breeding Drought-resistant and High-yielding 

 Spring Wheat. V. P. Kuzmin (U.S.S.R.). 



Success of breeding depends on correct deter- 

 mination of plants' characters according to the 

 character of environment that forms, preserves 

 and intensifies these characters. 



Central Kazakhstan has a peculiar arid cli- 

 mate: long cold periods in spring, abruptly 

 followed by hot dry weather in the beginning 

 of summer. Rains are typical for the middle of 

 summer, while the second period of drought 

 and early frosts are typical of autumn. 



The main sources of moisture for plants are 

 their deep subsoil reserves and rains in the mid- 

 dle of summer. 



Thus, to overcome drought and to make full 

 use of moisture, wheat breeding was aimed at 

 developing various varieties with different 

 development and growth rate, i.e. with proper 

 growth activity during the cold spring period 

 (early variety type) and with desirable growth 

 dynamics during summer rains. As for morpho- 

 logical characters the greatest attention was 

 paid to the development of the root system. 



The general method of work consisted of 

 hybrids training by environmental conditions and 

 selection in usual field conditions. 



Good results were obtained from Winter and 

 Spring wheat breeding: higher resistance to 

 spring frosts and drought. Hybrid training in- 

 cluded different sowing dates: very early, middle 

 and late. 



Breeding stock selected according to its ability 

 to produce a great number of good seminal and 

 crown roots was sown on limited fertile, moder- 

 ately warm and humid soil. This soil correspon- 

 ded to usual field conditions. Plant varieties de- 

 veloped by this method had a good root system 

 that did not degrade but became even stronger. 

 As a result the plant productiveness increased. 



Some Spring wheats were bred by this method; 

 they show in commercial trials the highest 

 yielding ability and annual stability of output 

 on the territory with peculiar arid climate. 



13.86. Controlled Modification of Heredity of Non- 

 winterhardy Varieties of Durum Wheat, Pea 

 and Two-row Barley into Winterhardy Crops. 

 V. F. Khitrinsky (U.S.S.R.). 



T. D. Lysenko has worked out theoretical 

 foundations of controlled modification of plant 

 heredity by training. In the Genetic Division 

 of the Ail-Union Institute of Plant Breeding and 

 Genetics (Odessa) we conduct experimental 

 work on controlled modification of heredity of 



durum wheat, pea and two-row barley into 

 winterhardy varieties. 



1 . 19 strains of winter durum wheat (7>. durum 

 Desf.) developed by training were investigated 

 at our Institute during the competitive variety 

 trials in 1962. The trials showed that as a result 

 of winter training non-winterhardy wheat chang- 

 ed hereditarily into winterhardy one. It changed 

 some physiological characters, including the 

 vernalization and light stages which became the 

 same as they are in common winter wheats. The 

 transformed durum wheat is safely wintering in 

 the field and endures low temperatures — up to 

 — -20°C. It is a good yielder (40-42 centners per 

 ha) resistant to drought, diseases and lodging 

 and its grain is of good quality. It was sown on 

 4 hectares in the autumn of 1962. 



2. As a result of autumn training 22 non-win- 

 terhardy Pisum arvense varieties (originating 

 from the U.S.S.R., Western Europe, Asia and 

 Africa) are purposedly transformed into winter- 

 hardy varieties. They acquired a new property- 

 winterhardiness. They have changed the duration 

 of growing period, habitus, colour of seed and 

 some varieties, even the form and size of seed. 

 Winterhardy pea is blooming and fruiting 2-3 

 weeks earlier than the non-winterhardy pea and 

 the yield of green mass is considerably higher in 

 the first case. 



Two varieties of non-winterhardy Pisum sati- 

 vum plants were transformed into a winter- 

 hardy variety by the same method. 



3. Experiments on controlled modification of 

 heredity of spring and winter crops included two- 

 row barleys: Hordeum distichum L. var. nutanus 

 Schiibl. and var. medicum Korn. There were 

 commercial varieties among them — Odessky 9, 

 Odessky 14 and others. As a result of training 

 we have controlled hereditary modification of 

 morphological, biological and valuable economic 

 characters adequate to autumn conditions. Win- 

 ter and alternate forms of two-row winterhardy 

 barley were developed from spring non-winter- 

 hardy two-row barley plants. The Odessky 17 

 commercial variety produced the average yield 

 of 34 centners per hectare and 97 strains of 

 transformed two-row barley yielded 37.3-56 

 centners. 130 best strains of transformed two- 

 row barley were sown on 1.5 ha in autumn of 

 1962. 



In conclusion it is necessary to note that using 

 plant training in particular conditions, it is 

 possible to modify and control their heredity 

 developing new varieties with desirable charac- 

 ters. 



The method of controlled transformation of 

 spring non-winterhardy plants into winterhardy 

 ones has become a valuable method in the So- 

 viet plant breeding. 



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