ITEMS FROM RUSSIA

AGRICULTURAL RESEARCH INSTITUTE FOR SOUTH-EAST REGIONS - ARISER

410020 Toulaykov str., 7, Saratov, Russian Federation.

Influence of black-point damage on semolina speck content.

N.V. Vassiltchouk and V.M. Popova.

Semolina speck content depends both on the quality of the milling equipment and milling conditions, but to a greater degree on the amount of black point-damaged grain. Researchers have assumed that sensitivity to this disease is higher in larger-seed size varieties. In our studies, we did not find this direct connection. However, we have observed that large-seeded varieties as Saratovskaya Zolotistaya, Ludmila, and Valentina are very sensitive to damage, especially in years with high moisture during the period from flowering to maturity. We have found only one stable, resistant variety, Besentchukskaya 139, in all our years of study. An acceptable speck content in the U.S. must not be higher than 30/10 sq in or 12/10 sq cm. Thus, research on the influence of black-point-damaged grain content on semolina and flour after milling is important.

Grain samples with different amounts of damaged grain of two sensitive varieties, Hordeiforme 432 and Melanopus 1861, were used. Increasing black-point damage to grain also increases the speck content in flour and semolina. After strong sieving with aspiration, the speck number sharply decreased to acceptable levels, even in samples that contained only damaged grains. The number of specks in the sample of the resistant variety Besentchukskaya 139 did not exceed 5.3-6.0 pieces/10 sq cm. Beginning in 1998, the restriction for black-point durum grain content received at mills in Saratov specializing in semolina production can not be higher than 8 %. However, we believe this level is too low, because even without sieving, the number of specks is at an acceptable level when the damaged grain content is 15 %. Obviously, it is important to develop milling procedures, but grains to be used for milling must be free from disease. As long as no varieties are resistant to black point, seeds must be treated by fungicides, followed by good cultural practices. Thus, the most important task facing durum wheat breeding is to develop varieties resistant to this decease.

Drought- and heat shock-induced changes in the electrophoretic spectra of proteins in wheat seedlings.

Yu.V. Italianskaya and S.V. Tuchin.

Eight-day-old seedlings of the drought-resistant bread wheat cultivar Saratovskaya 29 (S 29) and the drought susceptible cultivar Opal were analyzed for esterase isozyme profile by PAGE. The osmotic reagent polyethylene glycol (PEG) was added to the growth medium in different concentrations (14-30 %) to induce water stress. The electrophoretic pattern of the drought-resistant cultivar differ markedly from that of susceptible Opal. Increased synthesis of HMW isozymes under water-stress conditions increased the resistance of S 29. Only the highest concentrations of PEG (26-30 %) caused an appearance of minor LMW bands with a simultaneous decrease in HMW-isozyme activity. In the drought-susceptible Opal, these LMW bands were observed at the lowest PEG concentrations (14-18 %). Further increases in PEG content in the medium led to an appearance of a large number of weakly active isozymes in Opal, and the sythesis of HMW bands was sharply decreased.

Both cultivars also were studied for the response to heat stress. Seedlings were assayed for heat-shock proteins (HSP) induced after a temperature stress (41°C, 120 min) and analyzed by PAGE. The drought-resistant cultivar S 29 is known to have an increased synthesis of the 24 and 18 kD group HSPs. Some new proteins bands in the area of 14 kD in S 29 were not observed in Opal. Low-molecular weight HSPs are known to aid the regulation of mitochondrial energetics and protect them from heat-shock damage. These data may be useful for assessing the adaptive properties of new bread wheat lines.

The effect of Rht alleles on the wheat anther culture.

T.I. Djatchouk, O.V. Tkachenko, and Yu.V. Lobachev.

Many factors influence the frequency of haploid production by anther culture. Genotype is an especially strong determinant of the wheat anther-culture response. Specific genetic systems are known to influence different parameters of androgenesis. The Rht genetic system was found to influence wheat somatic embryogenesis. Therefore, we wanted to determine the effect of Rht genes on wheat anther-culture ability. A set of NILs created by Yu. Lobachev was used as donor plant material. These lines differ in alleles of the Rht genes (Rht1, Rht3, and Rht14 in the background of the bread wheat Saratovskaya 29 and Rht1 and Rht14 in the durum wheat Charkovskaya 46). In bread wheat, the dominant Rht3 gene has a significant effect both on callus induction and plantlet regeneration capacity as compared to a sib line (rht3). However, the dominant gene Rht14 had negative effects on the androgenic parameters. The rate of embryogenic anthers, callus yield, and plant regeneration were significantly lower. The Rht1 gene did not influence at the callus induction stage, but a statistically higher regeneration frequency confirmed its role at this stage of androgenesis. In the durum wheat background, Rht14 had a positive effect on plant regeneration, whereas callus induction frequency was equal to that of the sib line. The Rht1 gene did not influence haploid production in durum wheat anther culture.

Winter wheat selection for tolerance to fermentation damage by insects.

A.D. Zavorotina, N.A. Emelianov, E.N. Maslovskaya, G.V. Piskunova, and A.I. Pryanishnikov.

The climatic conditions in the Povolzhie region are favorable for the production of high-quality winter wheat. Two limiting factors in the production of such wheat are insect infestation of the crop and lack of tolerant varieties. The Scientific Research Institute of the South-Eastern region has been breeding new varieties of winter wheat that are tolerant to fermentation damage by insects since 1992. Tolerance does not adversely affect the bread-making quality, when meal is used with a mixture of the damaged grains. Scientists at our Institute have selected several tolerant varieties of winter wheat including Saratovskaya 8, Bezostaya 1, Tarasovskaya 89, and Belozerkovskaya 198. The best cultivar is Saratovskaya 8. When making crosses of susceptible varieties with Saratovskaya 8, tolerance is transferred at a rate between 33-100 %. Tolerant forms are selected in annual evaluations. Tolerant lines include Lutescens 37/84 (Saratovskaya 8 / Saratovskaya 10 // Saratovskaya 82), Lutescens 41/91 (Saratovskaya 8 / Saratovskaya 11), and Lutescens 38/96 (Saratovskaya 8 / Donskaya bezostaya). A new variety Viktoriya 95 has been selected that is strongly tolerant to fermentation damage by insects.

Development of winter wheats in the autumn relative to environment conditions.

S.V. Lyasccheva.

Between 1993-96, we studied the development of 15 varieties in the field during autumn. Plants reached maximum development in warm years (1994 and 1995). In 1994, the number of stems was between 9.15 and 13.6 in different varieties. In a moist year (1995), the number of stems increased to 9.8-16.8. Plant mass in a moist year was 1.83-2.68 g, compared to 0.39-0.47 g during a dry season. We observed the same dependence of stem number and plant mass on precipitation in cool autumns. In a dry year (1996), the number of stems was 2.5-3.6 compared to 3.4-5.1 in a moist year (1993). The cultivar Severodonskaya differed from others by its higher stem number, which was further related to the number of productive stems at harvest.

Saratov's spring bread wheat varieties have improved dough.

A.I. Kusmenko, R.G. Saifulin, K.F. Gurjanova, V.A. Danilova, T.K. Sotova, G.A. Becetova, I.I. Grigorjeva, S.D. Davidov, and O.V. Subkova.

The Povolzhie environment (a droughty, hot climate and soils rich in organic matter) is favorable for the development of high-quality grain (high protein and gluten content and excellent bread-making ability). The history of Saratov's famous bread (kalatch) began in the second half of the 11th century. Kalatchs, or saratovski, also were made in other Russian cities, but from flour of local bread wheats (Poltavka and Rusak) and durum wheat (Beloturka) growing in the Povolzhie steppes. The secret of Saratov's kalatch is in the specific properties of the flour. For baking, the mix was taken from durum (Beloturka) and bread (Poltavka and Rusak) wheats. Beloturka, with its highly vitreous grains and high gluten content and elasticity, was used to improve dough,. During 85 years of bread wheat breeding, Saratov's breeders have developed a set of hard wheat varieties that have revolutionized bread making. No longer is it necessity to mix flours of durum and bread wheat. Saratov's hard bread wheats are characterized by high protein content and high gluten quality, resulting in high bread-making quality. All of Saratov's hard bread wheat varieties are excellent for improving the dough of weaker varieties (Table 1, page 125). Addition of 30 % of a high-quality hard wheat flour to weaker one increases loaf volumes from 560 to 810 ml and dough texture from 3.0 to 4.8 points. In other words, bread quality increases to excellent with the quality of the dough improver. The new variety Saratovskaja 60 seems to be the best improver of dough.

Bread-making quality simultaneously increased with an increase in disease resistance. All of Saratov's new varieties have significantly higher yield potential compared to the first varieties developed for the west Volga region (Albidum 43) and for the east (Lutescens 62). The ranges of yield improvment for these varieties were 30-58 % and 18-40 % in favorable years and 32-58 % and 40-44 % during droughts. The important property of the latest wheat varieties is their improved response to the environment, including higher levels of resistance to leaf rust and powdery mildew and resistance to lodging.

On the growth of the vegetative organs in the shoot of spring wheat.

O.A. Yevdocimova, N.A. Zacharchenko, and V.A. Kumakov.

The linear growth of all metameres and their parts from imbibition of seed to end of the growth of the spike internode were observed daily in plants of the cultivar Saratovskaja 29 for 4 years. Plants were grown in the field at Saratov. We have elucidated some regularities in the morphogenesis of organ growth at a phenotypic level.

Intranode correlation. The first node begins inside of the coleoptile and differs in structure and nature of its growth. After emerging from the ground, the simultaneous growth of the initial leaf and its epicotyl is observed. The leaf sheath of the first leaf and epicotyl lengthen almost equally. In a healthy leaf, the average growth in the leaf sheath of the second, third, and fourth nodes is 1-1.5 mm/day after the tip of the given metamere appears. The growth of the fifth leaf sheath begins 2 days before that of the sixth leaf and 5 days before that of the seventh leaf. The periods of growth of the merithalli are similar. The merithallus of the fourth node begins to lengthen 5 days after appearance of the leaf's small awl, 3 days previous to that of the fifth merithallus, and 4 days prior to the sixth merithallus. The seventh and eighth merithalli arise when the awls of the corresponding leaves appear.

We can see a changes in the structure from germination to the upper nodes or accelerated growth. The leaf blade ends grow either simultaneously or 1-2 days previous to the reflexion of the leaf and blade from the vertical axis. The blade of an unbent leaf has not finished growth. The lateral bud of the first node (coleoptile) begins to grow in a few days after leaf bending, and buds of the next three nodes start 1-2 days previous. The fifth and sixth lateral buds sprout only in favorable conditions and simultaneously with the bending of earlier leaves. Lateral buds begin to grow much later than the leaf sheath of the leaves of a given node, and grow simultaneously in the tube under the leaf. The lateral shoot of the first node appears from the axil of the coleoptile 6 days after the end of growth of the first leaf. The second leaf and the fourth metamere apprear almost simultaneously with the termination of the growth of the leaf sheath. The germination of the lateral buds of the fifth and the following nodes may be delayed by a of lack of moisture or nitrogen. The buds may appear 4 days after growth of the leaf sheaths of the leaves of the corresponding nodes stops or may not appear at all.

Internode correlations. We can easily and more exactly judge the growth of the parts of the successive nodes of the seedling if we compare the beginning of growth of the next leaf with the appearance of the small awl of the previous leaf. The growth of a healthy leaf blade of every fourth node begins simultaneously with the appearance of the small awl of the previous leaf. Later, we observe the beginning of growth of the leaf blade by the appearance of a small awl of the previous leaves. For leaves of the fifth and sixth nodes, this occurs 1-2 days previous, and for leaves of the seventh and eighth tier, 4-6 days previous. An analogous structure is observed for the leaf sheath of the leaves or the merithalli of upper tiers. In internode relations, we can observe an acceleration of the upper nodes in relation to the lower nodes, similar to that observed for the leaves. The composition of the nodes and their parts that grow simultaneously consequently change during ontogeny.
Undoubtedly, this information on the concomitant growth of nodes and their parts is not exhaustive, but it is the start of the elucidation of the mechanisms of regulation of internode and intranode correlation.

Dynamics of nitrogen content in the organs of growing spring bread wheats.

K.N. Sher, I.A. Semyackhkin, N.A. Aleshina, N.A. Zacharchenko, O.A. Yevdocimova, V.A. Kylikova, and V.A. Kumakov.

In nature, plants usually have inadequate nitrogen nutrition. Different organs of a plant can have different degrees of nitrogen deficit, depending on differences in their relation to the source, their age, and their chemical composition. Changes in the nitrogen content of the organs of spring bread wheat from germination to death were studied. We compared organs of the main stem (flag leaf, upper internode, and spike).

These data were measured on plants of the cultivar Saratovskaya 29 grown in the field at Saratov. The first weights and nitrogen contents were recorded at the six-leaf stage. At this stage, the lengths of flag leaf and upper internode were 6-10 mm, and the length of spike was 3-5 mm. Thirty plants were selected from each of three replications. A second set of readings were taken when each organ ceased growth. Measurements were on 15 plants grown with (N140, P70) and without fertilizer.

The nitrogen contents in flag leaf, spike, and upper internode at the 6-leaf stage were similar. The average nitrogen level was 7-8 % in dry matter (protein is 40-50 %). Nitrogen content in the stems of fertilized plants at the 6-leaf stage was significant. The increase in nitrogen content in relation to the check was 39 %. However, leaves were weakly affected (9 %), and the spike was negatively affected (-19 %).

The lower nitrogen content of the spike at the 6-leaf stage under fertilized conditions when compared to unfertilized plants was combined with a significant increase in spike weight (weight of the spike, leaf, and upper internode increased 4.76, 4.01, and 1.42 times, respectively, with the application of fertilizers). Competition for nitrogen between differents organs (meristems) occurs under conditions of high nitrogen supply. This competition does not benefit the spike during its development. The stability of the nitrogen content of the spike, which may be observed occasionally, is not related to the availibility of nitrogen under conditions of high supply, but with the inability to compete for nitrogen with young growing organs when the supply is low. After linear growth, the increases in nitrogen contents were 3.39 and 3.70 % in the leaf, 0.78 and 0.87 % in the upper internode, and 1.72 and 1.8 % in the spike in unfertilized and fertilized plants, respectively.

Other experiments compared the dynamics of nitrogen content in the spikes and stems of a spring bread wheat cultivar Saratovskaya 29 and in the spikes of the spring durim wheat Har'kovskaya 46. samples were taken from boot to flowering at 3-day intervals and also after flowering.

We detected that nitrogen contents of the spike and upper internode during ontogenesis were similars. Nevertheless, each part of the stem had a different age; thus, the nitrogen content is different at each moment of ontogenesis. Furthermore, the gradient of the nitrogen content between different parts of stem are large. At boot for example, the nitrogen contents in the upper internode, the penultimate internode, and other parts of stem were 1.82, 1.08, and 0.47 %, respectively. Differences between species for nitrogen content in the spike from boot to waxy ripe grain were not detected.

Laboratory of Genetics and Cytology ­ ARISER, 7 Tulaikov st., Saratov, 410020, Russian Federation.

The growing conditions for spring wheat in 1998.

V.A. Krupnov.

In 1998, the growing conditions were extremely unfavorable for spring wheat. Only 45 mm of precipitation was received during the vegetative period. The average air temperature for May and June was 21.4°C, and the maximum was 39.9°C.

The number of days in 1998 with no moisture and high temperature was a record for the 20th century. In these conditions, the plantings at the ARISER fields after black fallow averaged grain yields of 820-900 kg/ha for all cultivars of bread wheat, nearly a sixfold decrease.

The response of spring bread wheat cultivars to extremely severe drought conditions in Volga Region.

S.A. Voronina, S.N. Sibikeev, V.A. Krupnov.

Droughts occurred in the Volga Region three times during the 4-year period from 1995-99, in 1995, 1996, and 1998. The droughts of 1995 and 1998 were extremely severe. In these periods under lack of moisture and high temperature, great differences were observed among the Saratov-bred bread wheat cultivars. Spike sterility is a particularity of drought during high temperatures at flowering and during grain maturation. Under these conditions, the grain yield of the old cultivar Lutescens 62 (released in 1924) was equal to the planting rate of 153 kg/ha. The unique adaptation of Saratovslaya 29 and that of a modern drought-resistant cultivar from a breeding effort in the 1980s, Saratovskaya 58, produced the grain yields three times higher than Lutescens 62.

The new cultivars bred at the Laboratory of Genetics and Cytology include L 503, L 505, Belyanka, and Dobrinya. These cultivars have resistance genes to leaf rust, powdery mildew, and some virus diseases and yielded 700-850 kg/ha higher than many other cultivars (Table 1). The disease-resistance genes from A. elongatum and A. intermedium in the background of many adapted cultivars not only increased resistance to heat and drought, but significantly increased grain yield of the resistant cultivars L 503, L 505, and Dobrinya in the absence of pathogens.

The positive effect of Lr genes or their combination on grain yield was confirmed by studies with two NIL pairs, L 400R (Lr23 and Lr14) and L 400S, and L 359R (Lr19) and L 359S. In droughty years, the effect of the Lr genes on grain yield in both NIL pairs was similar, 7.2 % for the Lr23/Lr14 NIL and 7.4 % for the Lr19 NIL. Over 6 years, the advantages in average grain yield of 7.1 % for resistant sibs of L 400R and 15.1 % for sibs of L 359R. The positive effect of Lr19 on grain yield was significantly higher than that of the Lr23/Lr14 combination.

A positive influence on heat and drought resistance was obtained in bread wheat lines derived from the wide hybridization between bread wheat and T. turgidum subspecies.

Agronomic traits of durum wheat cultivars and lines grown in the drought conditions of 1998.

V.A. Elesin and V.A. Krupnov.

Conditions were unfavorable for normal growth and development during the vegetative period of durum wheat crop in 1998. Hot, droughty weather significantly decreased the grain yields. In these extreme conditions, field yield trials determined the influence of leaf and ear color on durum wheat cultivar NILs.

The average grain yield for all durum wheat cultivars was extremely low, 194 kg/ha. This yield is three times lower than that during the drought and virus epidemic of 1995 (the average for all durum wheats was 470 kg/ha). The highest grain yields were produced by durum wheats Saratovskaya zolotystaya (261 kg/ha) and Ludmila (257 kg/ha). The lowest grain yield was in the old durum wheat Melanopus 69, which was considered to be drought resistant when it was released in 1929. Thus, the recently released durum wheats have higher drought resistance.

The NILs with red ear color proudced grain yields between 244-239 kg/ha, but their sibs with white ear color averaged between 17-238 kg/ha. NILs that differed from each other in leaf color produced equal grain yields.

The influence of wheat­alien genes on grain and pasta quality in spring bread wheat.

I.N. Cherneva and V.A. Krupnov.

The introgression of genes for resistance to leaf rust, powdery mildew, and some virus diseases from T. turgidum subsp. dicoccum, A. elongatum, and A. intermedium to bread wheat influences grain and pasta quality. Some of these genes, namely Lr19, Lr19d, LrAi1, and LrAi2, change the color of flour from white to yellow. Semolina flour from durum wheat generally is used to produce pasta, but often the flour of bread wheat also is used.

The possibility of using bread wheat­alien lines with translocations from T. turgidum subsp. dicoccum and A. intermedium for breeding of bread and pasta wheat was studied between 1995-97. The spring bread wheats Saratovkaya 58, lacking any alien translocation chromosome, and L 503 with an A. elongatum translocation with Lr19 and the spring durum wheat Saratovskaya zolotistaya were used as the check cultivars. The spring bread wheats yielded higher than the wheat-alien lines during the drought conditions of 1995, exceeding Saratovskaya zolotistaya by 2-3 times and Saratovskaya 58 by 1.5 times. During 1996, the wheat-alien lines outyeilded the check cultivars Saratovskaya 58 and Saratovskaya zolotistaya by 70 and 20 %, respectively.

Under optimal conditions in 1997, the bread wheat­alien lines produced grain yields approximately 60 % higher than Saratovskaya zolotistaya and equal to that of the high-yielding cultivar L 503. The 3-year averages of bread wheat-alien lines are 16.3 % for protein content, 269.3 e.a. for alveograph W, 44.6 % gluten content (group 1 preferable), 69.0 mm SDS-sedmentation value, and 836.3 cm3 loaf volume. These studies of bread wheat­alien lines identified lines with good or excellent bread-making quality.

To study the spaghetti-making quality of these lines, we determined spaghetti color, breaking strength, overcooking time, and the firmness of cooked spaghetti. The bread wheat-alien lines gave a lighter spaghetti color than Saratovskaya zolotistaya and approximately equal quality of cooked spaghetti. For the complex spaghetti making guality traits, the lines 786 (T. turgidum subsp. dicoccum-derived), 235 (A. intermedium-derived), and 773 (T. turgidum subsps. dicoccum and durum and A. elongatum derived) were the best.

Analysis of meiosis in the bread wheat­Secale cereale line 2837.

S.N. Sibikeev.

The gene pool of S. cereale includes many useful and desirable genes for bread wheat improvement. However, in the majority of cases, most of the genes are for resistance to pathogens. There are few reports on translocations from rye that increase resistance to abiotic stress such as drought resistance and winter hardiness. We have detected the influence of some genes for these traits.

The frost-resistance genes Fr1 and Fr2 are located on chromosome arm 5AL in bread wheat. Similar genes may be on homoeologous chromosomes in related wheat species. Therefore, we produced a spring bread wheat line 2837 (pedigree 'L 503 / S5 (winter rye) // L 503'), which successfully overwintered during 1996-97 and 1997­98. Meiotic analysis of L 2837 and F1 hybrids (L 2337 / L 503) had metaphase I configurations of 20" + 1T" + t" and 18" + 1T" + t', respectively. The line L 2837 has a rye translocation chromosome between the 5RL arm and an unknown bread wheat chromosome and two unknown rye telochromosomes. The Hp gene is a marker for chromsome arm 5RL. The increase in winter hardiness of L2837 to the level of that of winter wheat is under the influence of the frost resistance and winter hardiness genes on 5RL.

Single-pustule isolate, leaf rust analysis of spring bread wheat lines with Lr genes from S. cereale.

Yu.E. Sibikeeva*, S.N. Sibikeev, and V.B. Lebedev* (*Laboratory of Plant Protection).

The genes Lr25, Lr26, and Lr45 have been transferred from rye to wheat (McIntosh et al. 1998. Catalogue of Gene Symbols for Wheat. In: Proc 9th Inter Wheat Genet Symp (Slinkard AE ed). University Extension Press, Saskatoon, Saskatchewan, Canada. 5:134-139). The wide-hybridization program of the Laboratory of Genetics has released two leaf rust-resistant spring bread wheat lines 2075 and 2838 with Lr genes from S. cereale. Allelism tests, meiotic anaysis, and single-pustule leaf rust isolates were used to identify these genes. The results of the allelism tests and meiotic analysis have been published previously (Ann Wheat Newslet 1997, 44:172) Here we report on the analysis of 40 single-pustule isolates of leaf rust obtained from local populations in 1997.

Seedlings of Transec (Lr25), Thatcher (Lr26), L 2075, and L 2838 were inoculated at the 4-leaf stage. The Lr genes in these lines are different. Inoculation with single-pustule isolates identified genes that were virulent to one isolate and avirulent to others. These Lr genes were divided in three groups: 1. Lr gene from L 2838 and Lr25 (55 and 52.5 % of the avirulent isolates), 2. Lr26 (40 % of the avirulent isolates), and 3. Lr gene from L 2075 (12.5 % of the avirulent isolates).

In our previous article (Sibikeev et al. 1997, Ann Wheat Newslet 44:171), we reported on the absence of segregation between the Lr gene in 2075 and Lr26 in the F2 and detection of Sec-gliadin in both lines. However, the single-pustule leaf rust isolates differ in reaction to these Lr genes. This fact can be explained by different alleles of the Lr26 gene, different expression of Lr26 in different genetic backgrounds, or the effect of the genes in different parts of chromosome 1B.

The HMW-glutenin composition of old and modern bread wheats from ARISER.

V.M. Panin.

Twelve old (bred previous to 1990) and six modern spring and winter bread wheat cultivars were analyzed for their HMW-glutenins. The HMW-glutenins were extracted from half-seeds and separated by SDS­PAGE. The majority of old spring bread wheat cultivars (Lutescens 62, Saratovskaya 29, Saratovskaya 55, and Saratovskaya 58) and all modern cultivars (L 503, L 505, Dobrinya, and Belyanka) have the same HMW-glutenin pattern: 2* (Glu-A1b), 7 + 9 (Glu-B1c), and 2 + 12 (Glu-D1a). Only 2* is associated with high bread-making quality. In the cultivars Ershovskaya 32 and Saratovskaya 54, the HMW-glutenin subunits 5 + 10 (Glu-D1d) were found. These subunits are not widespread among the Saratov-bred bread wheat cultivars. In Ershovskaya 32, the HMW-gluten subunits 17 + 18 (Glu B1c) were detected. The HMW-subunits 5 + 10 and 17 + 18 are recomended for increasing bread-making quality.

The alleles of HMW-glutenin subunits from the high-quality wheat Ershovskaya 32 were transfered, and promising lines produced. However, the HMW-glutenin pattern 2*, 7 + 9, 2 + 12 is widespread in Saratov-bred wheats and possibly connected with their ability to adapt to the drought conditions common in the Volga Regions. The HMW-glutenin subunit composition of the old winter bread wheat Saratovskaya 8 and the modern cultivars Victoria and Gubernia was 1 (Glu-A1a) and 5 + 10 (Glu-D1d). In addition, Saratovskaya 8 had alleles Glu-B1c (7 + 9) and Victoria had Glu-B1b. The 6+ subunit in Gubernia is commonly inherited together with subunit 8 (Glu-B1d). The 6+ subunit is more common than 6 and probably compound, suggesting that it is a novel allele indentified in locus Glu-B1.

We also discovered two subunits that phenotypically coincided with w-secalins, which are controlled by Sec1 on rye chromosome 1RS and present in Kavkaz. By testing individual seedlings for leaf rust reaction, we identified Lr26, confirming the presence of chromosome T1BL·1RS in Gubernia.
Glu-B1d).

The search for cultivars and lines of spring bread wheat resistant to powdery mildew.

A.E. Alexandrov and S.N. Sibikeev.

More than 200 cultivars and lines of spring bread wheat were evaluated for resistance to powdery mildew after natural inoculation in the field and greenhouse. Most of the materials were hybrids between T. aestivum and A. intermedium, A. elongatum, S. cereale, and other alien species of wheat. The highest levels of resistance were in L 1740, possibally with Pm-resistance genes from A. intermedium and L 400, which we suspect has the gene combination Pm4 + Pm5. This combination was confirmed by screening NILs of L 400 for Lr genes. NILs lacking Lr23 are more susceptible to powdery mildew. The newest powdery mildew-resistant lines (multi Lr6R) has an as yet unknown Pm-resistance gene from rye. The highest resistance to powdery mildew is in hybrids of T. aestivum with T. turgidum subsp. dicoccum and Ae. umbellulata and the lines with Pm7.

Reaction of cultivars and lines of bread wheat to loose smut.

A.E. Druzhin and V.A. Krupnov.

Resistance to loose smut in T. aestivum was studied during 1997­98 by artificial inoculation. Six resistant bread wheat cultivars, Saratovskaya 29, Saratovskaya 55, Saratovskaya 58, L 503, L 505, and Belyanka, and five lines, L 164, L 528, L1089, L 2040, and L 2358, were investigated. These cultivars and lines have different levels of resistance to loose smut under field conditions.

Dry spores were suspended in distilled water (1.5 g/l) by repeated vortex-mixing and then filtered though muslin to remove debris. Wheat heads with yellow but undehisced anthers were selected. Less-developed florets within a selected head were removed before inoculation. Inoculations were made using a medical syringe containing the spore suspension attached to a hypodermic needle. One drop (approximately 0.05 ml) of spore suspension was deposited in each floret. At maturity, seeds from inoculated heads were sown as head rows, and the number of smuted heads was calculated.

PRYANISHNIKOV RESEARCH INSTITUTE OF FERTILIZERS AND AGRICULTURAL SOIL SCIENCE

Pryanishnikova str. 31, 127550 Moscow, Russian Federation.

Generative development of wheat at an elevated atmospheric concentration of CO2 and varyng nitrogen nutrition and watered conditions.

N.V. Pukhal'skaya.

Introduction. The influence of elevated CO2 on grain productivity is time and condition dependent. Increases in the average apex size and spikelet number (Pukhal'skaya 1997) have been reported for grains grown at elevated CO2. Changes in apex morphology may be regarded as a consequence of increased of carbohydrate availability in the shoot resulting from stimulated photosynthesis. The present study characterized the long-term growth response of wheat plants at elevated CO2 and related changes in apex morphology as a result of interaction between carbon and nitrogen metabolism in optimal conditions and under water stress.

Materials and methods. Wheat plants of the cultivar Rodina were grown from seeds in soil in a phytotron at 23°C/17°C day/night temperature; relative humidity was maintained at 60 %. The light period was 16 h. Air temperature and carbon dioxide concentration, 350 ppm (ambient) and 700 ppm (elevated), were controlled automatically. For each CO2 concentration, there were two levels of nitrogen nutrition (low, 100 mg N / kg soil and high, 600 mg N / kg soil) and two levels of water stress (a well-watered control and water-stressed plants, 8 and 10 days without watering at 350 and 700 ppm CO2, respectively). These periods resulted in the same rate of water stress. Water stress was initiated at developmental stage 6. Phosphate and potassium nutrition were applied to the soil at the rate of 500 mg/kg. The development of generative organs on the wheat apex was assessed using the Kuperman scale. Apex development was evaluated on the following stages: stage 3, elongation of the upper part of the apex and differentiation of its lower part into individual segments (the third leaf on the main shoot); stage 6, formation of stamens, embryo sac, and pistil stigmata (the sixth leaf on the main shoot); stage7, rapid growth of rachis, glumes, and awns; and stage 12, complete ripeness.

Results. Photosynthesis of wheat plants grown at 700 ppm CO2 was higher and respiration lower than in plants grown under 350 ppm CO2 at optimal water conditions and was the major reason for activation of growth at elevated CO2. As a result, the spikelet number in the apex in elevated CO2 plants was 212.2 in low N plants and 185.6 in high N plants. In the control plants at 350 ppm CO2, spikelet number was 193.1 in the low and 147.0 in high N plants (LSD 0.05 = 9.7). Thus, the 10 % increase in the number spikelets at the low level of N and the 26 % increase at the high level were in addition to that contributed to by CO2 enrichment of the atmosphere. We were surprised that high nitrogen levels led to a decrease in the number of spikelets. Nitrogen may have prolonged the period of spikelet differentiation. The main pool of carbohydrates was translocated to more spikelets. An elevated CO2 level changed the duration of certain stages of growth; stage 3 was shorter, and stages 7 to 12 were longer.

A shorter stage 3 led to a reduction in the length of the spike. At high nitrogen levels, the spike length was reduced from 8.87 cm (350 ppm) to 8.27 cm (700 ppm) (LSD 0.05 = 0.25). At low nitrogen levels, the length was not differerent, 8.18 cm (350 ppm) to 8.12 cm (700 ppm). Our results indicate that the productivity level of CO2-enriched plants was 16 % (low N) and 45 % (high N) higher than that at ambient CO2 levels. High CO2 concentrations reduced the negative influence of water stress, because dehydration of tissue was delayed. Under an elevated CO2 level, the rate of spikelet death as a reaction to water stress was 50 % lower than at ambient CO2 levels. Apparently, more spikelets were injured at the beginning of water stress. Productivity under water-stress conditions was estimated to be grain masses of 1.18 g under ambient and 1.45 g under elevated CO2 levels. Nitrogen nutrition levels had no influence wheat productivity under water stress.

References.

Pukhal'skaya NV. 1996. Generative Development of wheat at elevated atmospheric CO2 and differing levels of ni trogen nurition. Dokl RASKhN 3:7-8.

Pukhal'skaya NV. 1997. Growth and CO2 exchange in wheat seedlings grown at an elevated concentration of CO2. Russian J Plant Physiol 44:172-176.

Pukhal'skaya NV. 1997. Generative development of barley at an elevated atmospheric concentration of CO2 and varying temperature conditions. Russian J Plant Physiol 44:177-182.