GrainGenes

THE RUSSIAN ACADEMY OF AGRICULTURAL SCIENCES
Institute of Agricultural Employment of Reclaimed Land, Tver, 171330, Russia.

Genealogical analysis of spring bread wheat cultivars included on the Russian Official List ­ 1997.

S. Martynov and T. Dobrotvorskaya.

Our objective for this study was to determine the overall pattern of relationship within the spring bread wheats recommended for different regions of Russia based on their pedigree information. For cultivars of self-pollinated species with known pedigrees, a coefficient of parentage (COP) can provide an inexpensive estimate of genetic similarity and can be used as an indicator of latent diversity within and between cultivar groups or growing regions.

The Official List 1997 includes 120 cultivars recommended for 12 regions. With the exception of five cultivars with unknown or questionable pedigrees (Kurskaya-2038, Kamyshinskaya-3, Niva-2, Tjalve, and Valeriya), 115 cultivars were used for the analysis (Table 1). With the aid of the Genetic Resources Information System (GRIS3) the percent similarity of the cultivars was examined using COP and computed for all 6,555 pairwise combinations of the cultivars from pedigree information. Cluster analysis was done on the COP matrix using a hierarchical agglomerative algorithm.

Arbitrarily selecting a minimum within-cluster mean of r = 0.25 (this COP level is equal for half-sibs) and minimum cluster content of three cultivars, we obtained 10 clusters (Table 1). Only 13 cultivars (11 %) were not incorporated into any cluster. The predominant parents or ancestors shared by cultivars within the cluster were: A, Saratovskaya-29, 36, 46; B, Novosibirskaya-67; C, Skala and Irtyshanka-10; D, Mironovskaya-808; E, Ershovskaya-32 and PV-18; F, Bezostaya-1; G, Marquis; H, Zarya and Belorusskaya-12; I, Skorospelka uluchshennaya; and J, Strela. Mean values of COP within the 10 clusters ranged from 0.20 to 0.45, with an average of r = 0.30. These values were much higher than those between clusters (r = 0.03 on average). Thus, the cluster analysis was correct.

Cluster A was the largest with 41 entries and included two closely related subclusters, A-1 (predominant parent is Saratovskaya-46) and A-2 (predominant parents is Saratovskaya-29) containing nine and 25 cultivars, respectively. Mean COP values were 0.41 and 0.33, respectively, within subcluster, and 0.23 between subclusters. A large share of the strong wheat cultivars (73 %) is found in cluster A. Using this index, only cluster B, which included 60 % strong wheats, was near cluster A. The share of strong wheats was less in clusters C and D (approximately 40 %). Clusters H, I, and J included only weak wheats. Most of cultivars developed from 'spring x winter' crosses were included in clusters D and F and have poor quality as a rule. These results indicate that the cultivars Saratovskaya-29, Saratovskaya-36, and Saratovskaya-46, with high quality from the interspecific hybrid 'T. durum / T. aestivum', are the donors of high milling and baking qualities. Among the strong wheats, 80 % had these cultivars as parents or grandparents. Derivatives of Novosibirskaya-67, whose pedigree contains a 'T. durum / T. aestivum' hybrid are mostly strong wheats.

To estimate the spatial genetic diversity, the average COPs within groups of cultivars recommended for different regions were calculated. For the northern region (code 1), only one cultivar was recommended. Therefore, the average within-region values of COP were calculated for 11 regions with codes 2-12 (Table 2).

Some cultivars are recommended for use in several regions; therefore, the total number exceeds the number of cultivars from the Official List (115). The genetic diversity among cultivars recommended for use in most regions was rather high. The average COP values for the different regions ranged from 0.05 for the Volga­Vyatka region to 0.14 for the North-Caucasus. In contrast, the cultivars proposed for use in the Lower-Volga region were more similar (r = 0.33). This corresponds to cultivars having an average relationship silimar to that between half-sibs and full-sibs (Table 2). The lower diversity among cultivars from this group is because of all the wheats were developed by the Saratov Breeding Centre. This situation is dangerous, because the actual diversity probably is lower than the recommended diversity, and a narrow genetic base may increase a crop's latent vulnerability to disease and other biotic and abiotic stresses.

The diversity of cultivars from different market classes, which estimated average values of COP, were 0.14 for strong, 0.06 for filler, and 0.05 for weak wheat. The sources of high milling and baking qualities of the Saratov spring wheats were the landrace Rusak and the interspecific hybrids Sarrosa and Sarrubra that were developed by means of crosses between the landraces Beloturka (T. durum) and Poltavka (T. aestivum). Developed on this ancestral base, germplasm was used to create strong wheat cultivars not only by the Saratov Breeding Centre, but also by other breeding institutions in different regions of Russia over a long period of time, resulting in a decrease of genetic diversity among strong wheats. Therefore, the quest to find new sources for high milling and baking quality remains a high priority.

 

SARATOV VAVILOV STATE AGRICULTURAL ACADEMY
Department of Biotechnology, Selection and Genetics, 1 Teatralnaya Sg., Saratov 410600, Russia.

Effects of six Rht-genes in spring bread wheats of the Volga Region.

Yu.V. Lobachev, A.I. Zavarzin, and E.A. Vertikova.

The yield capacity of the taller cultivar Saratovskaya 29, a NIL, and the short-stemmed backcross lines (L Rht1, L Rht5, L Rht8, L Rht14, L RhtML, and L RhtR) was studied from 1996-97 under the following conditions: nonirrigated, irrigated, fertilizer irrigated (N 120, P 100, K 60), fertilizer irrigated (N 180, P 160, K 100).

All the genes studied resulted in significant decreases of plant height by 14-23 % on the average. No significant differences in grain yield occurred between Saratovskaya 29 (2.34 T/ha) and short lines in nonirrigated fields.

In irrigated fields, only lines with Rht8 and RhtR had significant decreases in grain yields, of 22 % and 30 %, respectively, compared with the check Saratovskaya 29 (2.52 T/ha). In fertilizer-irrigated fields (N 120, P 100, K 60), only lines with Rht5 and RhtR had significant decreases in grain yields, of 13 % and 20 %, respectively, compared with Saratavskaya 29 (3.28 T/ha). In fertilizer-irrigated fields (N 180, P 160, K 100) only lines with RhtR had a significant decrease in grain yields, of 29 % compared with Saratovskaya 29 (3.61 T/ha).

The cultivar Saratovskaya 29 had an average yield of 2.94 T/ha. No significant differences occurred between the lines with Rht1, Rht14, RhtML, and the standard cultivar. The genes Rht5, Rht8, and RhtR decreased grain yields by 9, 11, and 25 %, respectively.

Thus, the genes Rht1, Rht14, and RhtML are the most important genes for breeding short varieties of spring bread wheats for both irrigated and nonirrigated conditions in the Volga Region.

Effects of gene Rht 14 in spring bread and durum wheat.

Yu.V. Lobachev, R.G. Sayfullin, Yu.V. Titova, and O.A. Zheludkova.

To define the effects of reduced height gene Rht14 on some selection traits of spring bread and durum wheat, we studied the NILs (Rht14 and rht4) in the backgrounds of cultivars Saratovskaya 29 (T. aestivum) and Harkovskaya 46 (T. durum). Cultivars and NILs were grown at the Saratov Agricultural Research Institut for South-East Regions in 1997.

Observations, selection of samples, and analysis were done by the standard methods. Results were treated by the dispersion method with comparisons according to Duncan's test.

Gene Rht14 decreased plant height of bread wheat 25.3 % and that of durum wheat 33.9 %. The differences in grain yield of the bread wheat studieds were not significant, with an average grain yield of 3.58 T/ha. Gene Rht14 in bread wheat did not influence the quantity of plants and ears/ha; the number of spikelets/ear or grains/ear; 1,000 kernel weight; harvest index; SDS-test; nitrogen content in aboveground biomass at tillering, flowering, and harvesting; or the grain nitrogen content.

The differences in grain yield of the durum wheats studied were not significant, with an average grain yield 3.20 T/ha. The Rht14 gene of durum wheat did not influence the number of plants and ears/ha; the number of spikelets/ear or grains/ear; 1,000-kernel weight; SDS-test; nitrogen content of aboveground biomass at tillering, flowering, and harvesting; or the grain nitrogen content. Rht14 in durum wheat increased the number of grains/ear by 47.4 % and harvest index by 40.0 %.

This information may be useful for breeding short-stemed varieties of spring bread and durum wheats with Rht14.

VAVILOV INSTITUTE OF GENERAL GENETICS

Gubkin str. 3, 117809 Moscow, Russia.

Distribution of hybrid necrosis genes in winter wheat genotypes.

V.A. Pukhalskiy and E.N. Bilinskaya.

Introduction. The available data on necrotic genotypes in aboriginal wheat varieties, which belong to T. aestivum, none allowed intensified research on wheat gene geography (Zeven 1966; Tsunewaki and Nakai 1967; Pukhalskiy 1975) and wide use for wheat phylogenetic studies (Mori and Tsunewaki 1992). The information on the presence or absence of hybrid necrosis genes in the genotypes of particular wheat varieties is very useful for the selection of the original material at breeding, especially if we take into consideration that a procedure for selecting wheat plants with a compensational gene complex in necrotic combinations under a hybrid necrosis background has been developed ( Strunnikov 1994; Shamanin 1994). The results presented in this communication belong to a series of papers concerned with hybrid lethality genes in the genus Triticum.

Materials and methods. The varieties used in this work were obtained either directly from cultivar originators or from the State Crop Testing Commission. The varieties employed as testers are given in Table 1. Crossings were conducted in the field with spike isolation according to standard procedures. The F1 and F2 hybrids were grown both in the field and in the greenhouse. The expression of hybrid necrosis traits was recorded at different ontogeny stages.

References.

Mori N and Tsunewaki K. 1992. Distribution of the necrosis and chlorosis genes in two wild tetraploid wheats, Triticum dicoccoides and T. araraticum. Jpn J Genet 67:371-380.

Pukhalskiy VA. 1975. Geographic distribution of the hybrid necrosis genes in the USSR. Vest Skh Nauki 8:49 56.

Pukhalskiy VA. 1997. Analysis of necrotic genotypes in Triticum aestivum L. cultivars produced in the former USSR republics. Ann Wheat Newslet 43:202-204.

Pukhalskiy VA, Rybakova MI, and Iordanskaya IV. 1998. Selective inheritance of necrotic genotypes in winter common wheat. Dokl Ros S-kh Akad 1:3-4.

Shamanin VP. 1994. Breeding of spring common wheat under dry conditions of Western Siberia and Southern Urals. Dissert Cand Sci (S-kh), Novosibirsk State University. 36 p.

Strunnikov VA. 1994. Heterosis and the methods for its improvement. Moscow, Nauka 108 p.

Tsunewaki K and Nakai Y. 1967. Distribution of necrosis genes in wheat. III. U.S. common wheat. Canad J Genet Cytol 9:385-393.

Zeven AC. 1966. Geographical distributation of genes causing hybrid necrosis in wheat. Euphytica 15:281-284.

(This work was partly supported by the Russian State Program "Frontiers in Genetics".)