GrainGenes

ITEMS FROM UKRAINE

KHARKOV NATIONAL UNIVERSITY
Department of Plant Physiology and Biochemistry, Svoboda sq. 4, Kharkov, 61007, Ukraine.

Activation of the phytochrome system and status of phytohormones at vernalization in winter wheat seedlings. [p. 165-167]

V.V. Zhmurko and O.A. Avksentyeva.

The speed of development in soft wheat is determined by three genetic systems: Vrn genes, which control vernalization; Ppd genes, which control of photoperiodical sensitiveness; and genes for early maturation (per se) (Stelmakh 1998). Today, the genetic effects of these systems are well known. However, effects of Vrn genes on physiological functions are unknown. Particularly, the possible participation of phytohormones and phytochromes in regulating of these genes expression is not examined. Phytohormones are known to 'start' entire morphogenetic processes. The possible mechanism of this process consists of depressing one or more genes. One hypotheses to explain the effects of phytochromes in plants is that activation of phytochromes by red light determines the action of gene expression that takes place (Fedenko et al. 1999; Tarchevski 2002).

Based on these facts, we presume that expression of Vrn genes in soft wheat can occur as result of phytohormones and phytochromes actions. Until now, this question has not been addressed in the literature, although understanding he mechanisms of physiological regulation of gene expression of development wheat and mechanism of ontogenesis in plants is very important.

The winter wheat Mironovskaya 808, which has recessive Vrn genes, can not form spikes unless vernalized. Seedlings were vernalized for 60 days at 0-2 C with red (660 nm) and far-red (730 nm) light and out light (control). Phytohormones, gibberellin (GA), indoleacetic acid (IAA), cytokinin, and abscisic acid (ABA) activities were effected.

The results show that vernalization determines modifications in the level of phytohormones in winter wheat. Phytohormone activity effects growth (IAA and GA), decreasing until day 45 and increasing before the end of vernalization (day 60). Phytohormone activity that depressed the growth (ABA). No variation in cytokinin activity was observed.

Phytochromes are the main photoreceptor system of plants and control the regulation of many biochemical, physiological, and morphological processes (Fedenko et al. 1999). Vernalization determines the rate of development in winter wheat, the ability to flower. Changes in the dynamics of phytohormone activity in winter wheat seedlings regulate development. Most likely, these systems interact in the regulation of the vernalization processes.

The influence of phytochrome activation on GA activity show that red light inhibits GA activity on day 30 compared with the control and the far-red and red + far-red light treated plants. Red + far-red light had the greatest impact on GA activity in comparison to all other experimental treatments (Table 1).

IAA activity on day 30 of vernalization was the greatest with red + far-red light irradiation and lowest under far-red light irradiation compared with the untreated control seedlings. Phytohormone activity was reduced under red and far-red light until vernalization was complete (60 days). Activity increased in the control, but almost did not change under red + far-red light irradiation. Only IAA activity on day 60 was lower in the control then in the treated seedlings (Table 1).

Cytokinin activity on day 30 was the highest under far-red light and equal in all other treatments. During the next 15 days of vernalization until day 45, cytokinin activity increased in te control and seedlings treated with red light, but decreased in seedlings treated with far-red and red + far-red light. Changes in the cytokinin activity were insignificant (Table 1).

ABA activity after 30 days of vernalization under the influence of red and far-red light and in the control were nearly equal, however higher than ABA activity under the influence of red + far-red light. Up to day 45 of vernalization, ABA activity increased in all variants, but more in those treated with red + far-red light, somewhat less under the influence of red light, still less in control, and least under the influence of far-red light. Until the end of vernalization (day 60), the activity of ABA in the control and seedlings under the influence of red light continued to decrease, but increased slightly in seedlings under the influence of far-red light and red + far-red light (Table 1).

The phytochrome activation system during vernalization determines changes in the activity of phytohormones. We propose that metabolic and phytohormonal processes take part expression of Vrn genes by activation of phytochromes. However, subsequent researches are necessary for definition of expression mechanisms.

References.

• Fedenko EP, Agamova SP, and Koksharova TA. 1999. Success of Cont Biology 119 (1):56-59.
• Stelmakh AF. 1998. Genetic systems regulation flowering response in wheat: Prospect for Global improvement. Kluwer Academic Publishers, the Netherlands. Pp. 491-501.
• Tarchevski IA. 2002. Signal system of plant cells. Science, Moscow. 293 p.

INSTITUTE OF PLANT PRODUCTION N.A. V.YA. YURJEV

National Centre for Plant Genetic Resources of Ukraine, Moskovs'kiy pr., 142, Kharkiv, 61060, Ukraine.

harmful flies (Diptera) in wheat field agrocoenosis. [p. 167-168]

Yu.G. Krasilovetz, N.V. Kouzmenko, S.I. Popov, and V.A. Tzyganko.

An important trend in ecological orientation of farming is to fulfill a complex of protective measures for reducing insect damage. Our studies are aimed at the reduction of harmful effect on winter wheat plants caused by Dipteran flies using some agronomic management methods that are based on growing resistant cultivars, optimizing crop-rotation systems and forecrops, mineral nutrition, and monitoring of dates and rates of planting. The studies were conducted at the Experimental Farm of the Plant Production Institute V.Ya. Yurjev (Eastern Forest-Steppe of Ukraine) during 2001-04. The farm has a typical deep-humus, chernozem on loess soil. The agrochemical indices of the plowing layer are humus, 5.38 %; mobile nitrogen forms, 17.8 mg/100 g of soil (average); phosphorus, 16.3 mg/100 g of soil; and potassium, 13.2 mg/100 g of soil.

Results.
Forecrops. During 2001-04, the forecrops of winter wheat were black fallow (manure 30 t/ha + (NPK)30 + N30) and dried peas (manure after effect 30 t/ha + (NPK)30 + N30). Total tillering and stem number/m^2^ at tillering stage (the third stage of organogenesis of winter wheat according to F.M. Koupermann) did not vary (Table 1). For example, the black fallow and winter wheat after dried peas treatment, total tillering was 4.3 and 4.1, respectively, and stem number/m2 as 1.8 and 1.7 x 10^3^, respectively. Black fallow is regarded to be the best forecrop for winter wheat compared with peas. To obtain the optimal number of productive spike-bearing stems (550-600 stems/m^2^), winter wheat is planted at different rates; e.g., in black fallow, 4.0 x 10^9^ germinating seeds/ha and after peas, 5.0 x 10^9^ germinating seeds/ha. Over the years of the study, average total shoot damage in winter wheat at the tillering stage by larvae of various Diptera spp. on black fallow was by 1.4 time less than that of dried peas. This index was 5.2 % on black fallow and 7.5 % after peas. Oscinella spp. dominated and damaged an average of 70.6 % of the shoots on black fallow and 59.5 % of shoots in winter wheat after dried peas. Less damage by Opomyza florum was observed, 29.4 % on black fallow and 40.5 % after peas. In 2004, Phorbia secures caused 0.2 % shoot damage. Averaged over the 3 experimental years, winter wheat grain yield on black fallow (6.5 t/ha) surpassed that after peas (5.5 t) by 1.0 t/ha.

Cultivar. On black fallow (manure 30 t/ha + (NPK)30 + N30), total tillering in the winter wheat cultivar Donetz'ka 48 surpassed that of the control Kharus by 13.7 %. Total tillering was estimated at 5.2 for Donetz'ka 48 and 4.3 for Kharus. Stem number/m^2^ in Donetz'ka 48 and Kharus was similar, 1.8 x 10^3^ stems/m2. According to the average indices, total damage to the stems by fly larva in Kharus was by 1.3 time less than that in Donetz'ka 48. Grain yield in Donetz'ka 48 (5.7 t/ha) was inferior to that of Kharus (7.1 t/ha) by 1.4 t/ha.

Fertilizer. The effect of fertilizer on total tillering (in case of black fallow) was not sufficient. The number of stems/m^2^ in the blocks with manure a application of 30 t/ha + (NPK)60 + N30 was 1.9, lower than that of manure 30 t/ha + (NPK)30 + N30 (1.8), with manure at 30 t/ha, (1.9), without fertilizers (1.6 x 103 pcs/ha. Thus, fertilizer increased this index by 11.1-15.8 % compared to the block without fertilizers. On average, the lowest level of damage to the shoots by fly larva was observed in the block treated with 30 t/ha manure (3.1) compared with the block without fertilizers (5.6 % damage).

According to the average data, a manure application at a rate of 30 t/ha increased winter wheat grain yield by 0.2 t/ha. Manure use at the rate of 30 t/ha (NPK)30 + N30 increased yield by 0.4 t/ha. In the block with 30 t/ha of manure (NPK)60 + N30, the yield improved by 0.4 t/ha compared with the block with no fertilizers. In areas of high soil fertility and increased phosphorus-potassium, the additional application of manure at 30 t/ha and (NPK)60 or (NPK)30 did not contribute to an increase in grain yield.

Sowing date. In the black fallow treatment (manure 30 t/ha + (NPK)30 + N30), total tillering in winter wheat at the first (10 September) and second (20 September) sowing dates surpassed that at the third date (30 September) by 13.6-15.6 %. Total tillering was 4.5 at the first date, 4.4 at the second, and 3.8 at the third. When the sowing date was much later, stem number/m^2^ was reduced from 1.9 x 10^3^ to 1.7 x 10^3^. At tillering, total damage to the shoots by fly larva that had overwintered was gradually reduced from the first (5.0 %) to the third sowing dates (2.5 %/. The average grain yield in winter wheat sown at the third date (6.8 t/ha) surpassed that of the second (6.5 t/ha) and first dates (6.3 t/ha) by 0.3 and 0.5 t/ha, respectively.

Sowing rate. In black fallow (manure 30 t/ha + (NPK)30 + N30) at the sowing rate of 4.0 x 106 germinating seeds/ha, total tillering was 4.8. At a rate of 5.0 x 10^6^ germinating seeds the tillering rate was 4.3. At the 5.0 x 10^6^ seeding rate, stem number increased to 2.2 x 10^3^/m^2^ compared to that at 4.0 x 10^6^ (1.8 x 10^3^ seeds/m^2^). Total damage of to the winter wheat shoots by fly larva in these treatments ranged between 5.8-7.1 %. Grain yield in winter wheat fields at a sowing rate of 5.0 x 10^6^ (6.6 t/ha) germinating seeds surpassed that at 4.0 x 10^6^ by 0.4 t/ha.

Identifying sources and donors of genes for resistance to covered smut of winter wheat in Ukraine. [p. 169-170]

V.P. Petrenkova, S.V. Rabynovich, I.M. Chernyaeva, and L.M. Chernobai.

Screening of 400-650 cultivars and lines of winter wheat during 2001-04 identified sources of resistance to covered smut within a group of modern world wheats and breeding material adapted to the local conditions. Analysis of the breeding material shows that only 7-10 % of winter wheat lines is characterized by resistance to covered smut (damage less than 10 %). Because of the low level of genetic protection in breeding lines, introducing new sources of disease resistance into breeding programs is important.

Covered smut is an extremely harmful disease and chemical seed pretreatment is needed. These chemicals are rather aggressive and can harm natural soil organisms. The pathogenic population of covered smut in Ukraine is comprised of two species, T. caries and T. laevis, with a wide range of the races. At present in the central part of Ukraine, the highly virulent race 37 has been replaced completely by the less virulent race 32 (Krivchenko 1984). In the south, the highly virulent race 40 has been succeeded by the less virulent race 11. In the eastern part of the Forest-Steppe, race 11 dominates (Radchenko 2003). As a result of significant changes in the race composition of covered smut in Ukraine, resistance genes Bt1, Bt2, Bt3, and Bt7 have lost their effectiveness, but Bt5, Bt10, Bt11, Bt14, Bt15, and Bt16 still are highly effective. In the Kharkiv Oblast, our data indicate that the pathogen population is predominantly represented by less virulent races 3, 5, and 16 of T. caries, the more aggressive races controlled by the numerous well-known Bt genes.

Winter wheat entries were planted in the infection nurseries of the Division for Plant Immunity to Diseases and Pests of our institute. To study resistance to covered smut, seed samples are inoculated with the spores of the covered smut pathogen from the local population and sown in a special nursery (Babayants et al. 1998). To control the quality of the inoculation and the conditions of its expression and spread, 20 susceptible cultivars chosen according previous data were sown in the infection nurseries.

In 2001-04, 396 selected and 566 collection cultivars and lines of winter wheat were studied for resistance to covered smut in the infection nursery. Based on plant damage in the susceptible controls, we identified sources of resistance within the range of 45-87 %. These resistant lines include winter wheats from the U.S. (Rod, Idaho 364, McVicar, CO900134, CO900166, WRBÝ86036, and T 96V2112), Winridge (Bt1, Bt4, Bt6, Bt9, and Bt10, pedigree Madsen (VPM/Moisson//2*HILL 81 (Yamhil/Hyslop (Bt1 and Bt4), and two lines singled out from an analogous cross in made in Oregon (resistance lasting for more than 10 years). The smut resistance in these lines was inherited not only from Hyslop, which is resistant to covered smut in our local conditions, but also from the French line VPM1 (an Ae. ventricosa-derived line) (Dolgova et al. 1996).

We also identified some modern Ukrainian cultivars with good agronomic traits that were resistant to covered smut including Lutescens 779/83, Erythrospermum 24220, Lutescens 2690, Lutescens 8589, Erythrospermum 26221, Columbia, and Ferugineum 220/85 (with effective genes Bt15 and Bt16). Ferugineum 220/85 is characterized by resistance to loose smut and brown rust and has high productivity and grain quality.

Among the lines with new, highly effective genes of resistance derived from the Aegilops, the crosses 'Ae. juvenalis/6*Chris//Selkirk', 'Ae. ventricosa/T. turgidum subsp. durum//3*Selkirk', 'Ae. tauschii/9*Selkirk', 'T. aestivum subsp. macha/9*Selkirk' are of interest.

Three lines released from our institute that can be used as a source of resistance are Erythrospermum 16-01, Erythrospermum 36-01, and Lutescens 157-01. These lines were selected for smut resistance in 2002 and remained resistance during a 2004 epidemic with a 4-9 % degree of infection.

We made test crosses in order to evaluate the cultivars Charmany and Idaho 352 for resistance to covered smut (Table 2). Resistance of these cultivars during all years of the study was very high, similar to that of the lines with the highly effective resistance genes Bt5 and Bt9-Bt17, which are effective against the local population T. caries. The hybrids derived from these resistant cultivars were resistant or highly resistant, indicating the presence of dominant genes in Charmany and Idaho 352 (Table 2). In the F2 of hybrids from crosses between the resistant cultivar Charmany and susceptible cultivars Kharkivs'ka 96 and Churaivna, the ratio of resistant and susceptible plants corresponded to the expected 13:3 ratio. Thus, the resistance in Charmany is controlled by two independent genes, one dominant and one recessive. In F2 of the cross combination between Charmany and Snezhinka, we observed segregation in the ratio of 15:1, which suggests the presence of two independent dominant genes. In crosses between the resistant cultivar Idaho 352 and three susceptible cultivars (Echo, Snezhinka, and Zolotava Nosivs'ka), the ration of resistant to susceptible plants corresponded to the expected 15:1 ratio, indicating two dominant genes for resistance in Idaho 352. Because we did not recover susceptible plants in the F2 in crosses between Idaho 352 and Kharkivs'ka 96 and Idaho 352 and Churaivna, possibly because of insufficient sampling or elimination of plants in the given class at the seedling stage, we did not make any conclusions concerning to these hybrids.

In conclusion, Charmany and Idaho 352 are the donors of resistance to the local population of covered smut and possess two independent genes; Charmany has one dominant and one recessive gene and Idaho 352 has two dominant genes.

References.

• Babayants LT, Meshterkhazi A, Bekhter F, et al. 1998. Methods of selection and evaluation of wheat and barley resistance to diseases. Prague, Czech Republic. 321 pp.
• Dolgova GM, Chernyaeva IN, and Afonskaya GG. 1996. Original material in breeding wheat for resistance to covered smut. Methodologic grounds of formation, management and use of plant genetic resources' collections. In: Proc Internat Symp, Kharkov, 2-4 October, 1996. Kharkov. p. 43.
• Krivchenko VI. 1984. Resistance to the pathogens of smut diseases in grain ear-bearing. M Kolos. 304 pp.
• Radchenko LM. 2003. Covered smut on winter wheat and the substantiation of immunologic methods of protection. Student Thesis in Agriculture, Kyiv. 140 pp.