V.A. Pukhalskiy, and I.V. Iordanskaya.
The interest in investigating the number of R
genes, which determine the grain color of wheat, is caused both
by commercial requirements for the varieties and the correlation
between grain color and the ability to resist sprouting in rainy
weather (Sarma et al. 1994). When grown under optimal conditions
for seed maturation, seed color has no impact on grain yield and
quality (Krupnov et al 1993). Sprouting greatly decreases the
milling and breadmaking quality (Derera et al. 1977). The inhibition
of sprouting is suggested to be controlled by the pleiotropic
effect of the R gene (it is not yet clear which of the
three R genes or all of them are involved) and some other
independent factor (Koval et al. 1991; McCaig and De Pauw 1992).
Such `independence' is relative. Attempts to transfer
this gene to the genotypes r1r2r3 were not always successful
(Gfeller and Svejda 1960; Freed et al. 1976; Soper et al. 1989).
At the same time, the R genes are good markers in selection
of forms that are more resistant to sprouting in breeding programs.
Thus, the investigation of the distribution of the genotypes with
different number of R genes is necessary. Furthermore,
our previous work demonstrated a specific geographical distribution
of R genes among the aboriginal populations of spring common
wheat (Pukhalskiy 1984). In this communication, we report our
data on the occurrence of R genes in the genotypes of modern
spring common wheat varieties produced in the former USSR.
Materials and methods.
We analyzed 58 cultivars of spring bread wheat (T. aestivum
L.) produced in different regions of the USSR (Table 1). Each
cultivar was grown under obligatory isolation for more than 2
years. The cultivars Kenya Farmer, Amby, and Turvey (r1r2r3
genotype) were used as testers. Crossing between the testers and
cultivars study according to standard procedures. The F1 and F2
generations were grown both in the field and greenhouse. To determine
color, the F2 seeds were put in 5 % NaOH for 90 min (Quartley
and Wellington, 1962). White kernels were straw-colored, whereas
red kernels were red-brown. The correspondence of the actual segregation
to the expected one (3:1, 15:1, and 63:1) was estimated by the
t-test (Snedecor 1957).
Table 1. The number of R genes in the genotypes of spring bread wheats examined.
_____________________________________________________________________________________________
Number
of R
No Cultivar Pedigree genes P
_____________________________________________________________________________________________
1. Kinel'skaya 40 Saratovskaya 210/Saratovskaya 29//Bezostaya 1 2 0.45-0.50
2. Zhigulevskaya 3 0.20-0.25
3. Ershovskaya 30 Bezostaya 1/Michurinka 2 > 0.99
4. Bezenchukskaya 128 Besostaya 1/Besenchuk 98 2 0.60-0.65
5. Lutescens 80 Mironovskaya 808/Saratovskaya 29 2 0.15-0.20
6. Kazanchulovskaya Lutescens 62/Mironovskaya 808 1 0.15-0.17
7. Luganskaya 5 Besostaya1/Saratovskaya 35 3 0.06-0.07
8. Otrada Odesskaya 13/Besostaya 1 2 0.25-0.28
9. Yaroslavna 2 0.90-0.95
10. Buryatskaya 79 Mironovskaya 808/Onokhoiskaya 2 0.23-0.30
11. Diana Bezenchukskaya 98/Mironovskaya 808 2 0.35-0.37
12. Omskaya 6 Mironovskaya 808/Saratovskaya 29 2 0.35-0.40
13. Luganskaya 3 Saratovskaya 36/Mironovskaya 808 1 0.05-0.07
14. Kinel'skaya 40 Saratovskaya 21/Saratovskaya// 2 0.27-0.30
(Besostaya 1 + Kanred + Butler + Anderson)
15. Bashkirskaya 20 Graecum 114/k-43030 (Introduction from Mexico) 1 0.25-0.30
16. Kuibyshevskaya 1 PV-18/Saratovskaya 29 3 0.30-0.35
17. Chakinskaya 2 0.90-0.95
18. Nevskaya Volna 2 > 0.99
19. Kuibyshevskaya 2 Sona 227/Bezenchukskaya 98 3 0.50-0.57
20. Leningradka 90 2 0.35-0.38
21. Ishevskaya Selection from Volzhanka 2 0.55-0.60
22. Krasnouphimskaya 90 Komsomolka1/Milturum 4 1 0.60-0.68
23. Chelyabinskaya 17 Skala/Pulo Fen 2 0.85-0.90
24. Tselinnaya Mironovskaya Yarovaya/Yubileinaya Tselinnaya 21 1 0.20-0.25
25. Lutescens 45 Stepova/Saratovskaya 29 2 0.85-0.90
26. Ishimskaya 88 Saratovskaya 48/Tselinnaya 21 1 0.25-0.30
27. Tselinnaya 24 Saratovskaya 29/Pirotrix 28//Saratovskaya 29 2 0.08-0.12
28. Gornostepnaya k-45061/Kazakhstanskaya 126//Kazakhstanskaya 126 1 0.25-0.30
29. Aktyubinskaya 1 0.20-0.26
30. Uiskaya Lutescens 5714/k-43095 (Introduction from Canada) 2 0.40-0.45
31. Khar'kovskaya 12 Khar'kovskaya 6/Luganskaya 4 2 0.76-0.80
32. Budimir 1 0.75-0.80
33. Kommunar Kalyan Sona/Saratovskaya 29 1 0.80-0.85
34. Diana 3 Wannon/Leningradka 1 0.85-0.90
35. Leningradskaya 88 1 0.55-0.60
36. Voronezhskaya CB-151/Karn 1 0.85-0.90
37. Erytrospermum 5 Introduction from Mexico/Mironovskaya Yub.// 1 0.40-0.45
Bezenchukskaya 98
38. Novosibirskaya 89 Moskovskaya 21/Saratovskaya 29 1 0.35-0.40
39. Novosibirskaya 22 3 0.70-0.75
40. Altaiskaya 50 Bezostaya 609/Skala//Saratovskaya 46 1 0.35-0.40
41. Altaiskaya 88 Ural'skaya 52/Omskaya 9 2 0.30-0.35
_____________________________________________________________________________________________
Table 1 (continued). The number of R genes in the genotypes of spring bread wheats examined.
_____________________________________________________________________________________________
Number
of R
No Cultivar Pedigree genes P
_____________________________________________________________________________________________
42. Krasnaya 83 Lutescens 330/M-431//Lutescens 51/Skala 1 0.05-0.07
43. Vetluzhanka Buryatskaya/Mana 2 0.85-0.90
44. Irkutyanka 90 1 0.60-0.65
45. Prilenskaya 6 k-45145/Skorospelka Uluchsennaya 1 0.30-0.37
46. Prilenskaya 19 Sonora 63/Skorospelka Uluchsennaya 1 0.75-0.80
47. Kazakhstanskaya Novosibirskaya 67/Rannyaya Omskaya 9 1 0.10-0.15
48. Karagandinskaya 70 Saratovskaya 36/k-42801 (Canada) 1 0.15-0.18
49. Kazakhstanskaya 10 Priboi/Strela 1 0.40-0.45
50. Ul'binka 30 Albidum 41339/Erytrospermum 841 2 0.60-0.67
51. Ul'binka 25 Albidum 43/Mironovskaya 264//Saratovskaya 29 1 0.75-0.80
52. Gong 1 0.15-0.20
53. Primorskaya 21 Erytrospermum 6/Akademicheskaya//Besostaya 1 1 0.35-0.40
54. Omskaya 19 Lutescens 1138-70/Lutescens 1210-10 2 0.30-0.35
55. Omskaya 18 Omskaya 11/Geines 1 0.20-0.25
56. Lutescens 121 Krasnovodopadskaya 210/Lutescens 34 1 0.05-0.06
57. Lutescens 25 Vendel/Saratovskaya 36 1 0.10-0.12
58. Rodina Verld Sidz/Kavkas 3 0.40-0.50
_____________________________________________________________________________________________
Results and discussion.
Our data on the number of R genes for each variety assayed
are given in Table 1. New cultivars of spring bread wheat carry
from one to three R genes. Cultivars with a single R
gene are most frequent, comprising 50 % of the cultivars scored.
The frequency of wheats with two R genes is 39.7 %; whereas
10.3 % of the cultivars have three R genes. On the whole,
the pattern observed is similar to that obtained for old aboriginal
varieties (Pukhalskiy 1984). However, certain differences are
observed. Thus, breeding leads to an increase in the frequency
of cultivars with a single R gene and to a highly significant
decrease in the number of genotypes with three R genes.
The maximum number of wheats were bred at Povolzhie, Zhigulevskaya,
Kuibyshevskaya 1, Kuibyshevskaya 2, Kinel'skaya 30 (Pukhalskiy
1984), and Saratovskaya 29 (Shulembaeva KK 1995). In this region,
sprouting in the field seldom occurs, implying that the R
genes are linked to other genes that significantly affect natural
selection pressure. This hypothesis is confirmed by the fact that
genotypes with two R genes are most frequent in this region.
In other regions of Russia and the former USSR, the genotypes
with one R gene prevail, although varieties from Povolzhie
are involved in the crosses. Modern breeding almost completely
eliminated genotypes with three R genes throughout the
entire Siberian region.
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