Indian Agricultural Research Institute
Division of Genetics, New Delhi, 110 012,
India.
S.S. Singh, H. Mehta, D.N. Sharma, and R.N. Sawhney.
DL 802-3: a high yielding wheat.
DL 802-3
is yet another high-yielding wheat genotype like Kanchan (DL 803-3),
but developed from a different cross combination `KUW202//KS-Frong-Sono64-K1Re/E4870
S310/HD 1944 mutant'
at the Indian Agriculture Research Institute, New Delhi. The
latter wheat was released officially by the Central Subcommittee
on Crop Standards, Notification and Release of Variety, in November
1994, for the timely sown irrigated conditions of the Central
Zone.
Yield potential.
A true potential for high yield, wider adaptability, and stable
performance over diverse agronomic situations are the basic hallmarks
of this genotype. The genotype was noticed at advanced varietal
trials of a coordinated wheat program spanning the entire Indo-Gangetic
Plains (North Western Plain Zone and North Eastern Plain Zone)
and peninsular India covering Maharashtra and Karnataka (Peninsular
Zone). The genotype scored convincingly over all the checks in
all the zones under late-sown irrigated conditions.
North West Plain Zone (NWPZ).
The genotype was tested for 3 years, from 1990-91
to 1992-93.
It realized an average yield of 40.6 q/ha and surpassed the best
checks from 1.3 (PBW226) to 5.7 (Sonalika) q/ha. The superiority
of DL 802-3 was conspicuously visible for 3 consecutive years
(Table 1).
Table 1. Performance of DL 802-3 in comparison to the standard checks in
the North Western Plain Zone under late-sown, irrigated conditions.
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Year DL 802-3 Sonalika HD 2285 PBW 226 LSD
____________________________________________________________
1990-91 38.9 32.3 37.9 38.1 1.5
1991-92 42.8 36.1 39.3 41.1 1.0
1992-93
40.2 36.4 36.0 38.7 1.0
Mean 40 6 34.9 37.7 39.3
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North East Plain Zone (NEPZ).
Here also, the genotype was tested for 3 years from 1990-91
to 1992-93.
An average yield of 35 q/ha was realized over 3 years of testing,
which clearly surpassed Sonalika (5.3 q/ha) and HP 1209 (4.8 q/ha)
(Table 2).
Table 2. Performance of DL 802-3 in comparison to the standard checks in
the North Eastern Plain Zone under late-sown, irrigated conditions.
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Year DL 802-3 Sonalika HD 2285 PBW 226 LSD
____________________________________________________________
1990-91 40.0 32.0 - 38.7 4.3
1991-92 33.1 29.3 31.0 33.7 1.1
1992-93
32.0 27.8 29.4 30.4 1.2
Mean 35.0 29.7 30.2 34.3
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Peninsular Zone (PZ).
The genotype was tested for 3 years in the PZ from 1991-92
to 1993-94.
It realized an average yield of 39.2 q/ha with marked superiority
over the checks, from 4.4 q/ha (Sonalika) to 2.1 q/ha (HD 2501)
(Table 3).
Table 3. Performance of DL 802-3 in comparison to the standard checks in the
Peninsular Zone under late-sown, irrigated conditions.
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Year DL 802-3 Sonalika HD 2501 HI 977 HD 2610 LSD
_____________________________________________________________________
1991-92 43.0 38.6 42.5 38.5 - 2.7
1992-93 37.2 33.9 34.7 34.9 - 1.3
1993-94
37.4 31.6 34.0 36.1 35.2 1.4
Mean 39 2 34.2 37.1 36.5 35.2
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Statewide performance of DL 802-3,
compared to the standard checks, revealed some interesting facts
about its versatile nature in terms of stable performance and
wide adaptability (Table 4). It registered first in the first
nonsignificant group in 1991-92
(Initial Varietal Trial), 1992-93
(Advance Varietal Trial I), and 1993-94
(Advance Varietal Trial II), consecutively, in both Maharashtra
and Karnataka states comprising the PZ, whereas none of the other
genotypes possessed this ability.
Therefore, the data clearly suggest
that the genotype was endowed with wide adaptability covering
diverse agroclimatic zones of the northern plains and the peninsular
India.
Reaction to some major biotic stress
factors. Brown, black, and
yellow rusts are the major biotic stress factors in the NWPZ in
descending order of importance.
Table 4. Statewide performance of DL 802-3 in the Peninsular Zone in comparison to the checks.
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Year DL 802-3 Sonalika HD 2501 HI 977 HD 2610
_________________________________________________________________________________
K M K
M K M K M K
M
1991-92 * * - * * - - * * -
1992-93 * * - - - - - - * *
1993-94 * * - - - - - - * -
_________________________________________________________________________________
K = Karnataka, M = Maharashtra.
* Denotes the standing of variety in
the first nonsignificant group.
Brown rust resistance.
Resistance to brown rust in this genotype was conferred by Lr26
and Lr23 in the Plant Pathological Screening Nursery (PPSN)
1992-93
and Lr34 (Adult Plant Resistance, Nayar et al.) in 1992-93
and 1993-94.
The average coefficient of infection (ACI) ranged from 0.1 to
0.8 (Table 5), indicative of highly effective resistance, whereas
the checks were found to be susceptible, with ACI values ranging
from 6.0 (PBW 226) to as high as 76.0 (HD 2285). However, in
the third year of its testing, it suddenly recorded high ACI under
natural (19.9) and artificial epiphytotic conditions (16.9), which
is difficult to relate with the resistant gene content postulated
for the genotype. Likewise, the ACI for brown rust, the major
production constraint in NEPZ, ranged from 0.1 to 0.8 (Table 6)
to 0.1 to 3.7 in the PZ (Table 7). However, in third-year testing,
the ACI values in these zones rose to 19.9 and 16.6, respectively.
Adult plant response patterns of DL
802-3 to the most virulent pathotypes, 77-5 and 77-1,
compared to the popular checks of the different zones showed some
interesting results (Table 8). It showed an infection rating
of 10 MR to 10 MS and a reaction type of the highly resistant
class (0 to 1). In comparison, the most popular checks, HD 2285
and Sonalika, scored 70S to 90S with the reaction type 33+ of
the susceptible class. These data are indicative of the tacit
operation of the slow rusting gene Lr34, which has been
seen to impart partial resistance in adult plants. Further, Lr34
is an interactive gene and should provide a higher level of resistance
along with other resistance genes, Lr23 and Lr26.
This, in turn, is expected to enhance the longevity of the resistance
gene.
Table 5. Reaction to major diseases in the North Western Plain Zone.
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Year DL 802-3 Sonalika HD 2285 PBW 226
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Brown rust
1991-92 (N) TS (0.7) 100S (74.0) 80S (40.0) 20S (6.0)
(A) 5 MS (0.8) 100S (73.3) 100S (55.0)
50S (13.2)
1991-92 (N) 40S (6.8) 60S (37.1) 60S (32.4) 30S (8.3)
(A) TR (0.1) 80S (58.0) 100S (76.0)
40S (38.0)
1992-93 (N) 40S (19.9) 80S (54.4) 90S (74.4) 60S (33.9)
(A) 40S (16.9) 100S (72.9) 100S (81.4)
80S (38.6)
Black rust
1990-91
(A) 0 40S 40 MR 10S
Yellow rust
1990-91 (N) 0 20S (20.0) 20S (20.0) TS
(A) 0 70S 10 MS 0
1991-92 (N) 0 60S (23.3) 30S (21.7) 0
(A) 0 60S 0 0
1992-93 (N) 0 40S (22.5) 40S (12.5) 15S (3.8)
(A) 5S (1.3) 60S (34.0) 40S (10.2) 30S (7.5)
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N = Natural, A = Artificial inoculation. Figures in parentheses indicate the average
coefficients of infection.
Even if we assumed that the genotype was infected with races having the combined virulence for Lr23 and Lr26 at all the centers, a disease score of 40 MS should be expected instead of 40S, because isogenic lines with Lr34 record a disease score up to 40 MS. This discrimination of the genotypes from a moderately susceptible class to the susceptible class can be made by expert eyes under field conditions. Another attribute worth mentioning is in the slow rusting behavior of Lr34. The possible transition of this genotype from the moderately susceptible category (40 MS) to susceptible class (40S) at the terminal stage of plant growth is most likely to be inconsequential in the final yield formation. Therefore, it becomes imperative to study the functional regulation of adult plant resistance genes under different temperature regimes and developmental stages, which might explain many such anomalies. Such studies may help in structuring some useful benchmarks in defining resistance thresholds based on a more accurate scientific basis towards the identification/release of genotypes that otherwise were highly versatile in relation to their productivity, adaptability, and stability.
Table 6. Reaction to brown rust in the North Eastern Plain Zone.
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Year DL 802-3 Sonalika HP 1209 HUW 234
__________________________________________________________________
1990-91 (N) 0 40S (37.5) l0S (2.4) 5S (2.5)
(A) 5 MS (0.8) 100S (73.3) -
80S (38.4)
1991-92
(A) TR (0.1) 80S (58.0) 40S (16.1) 80S (64.0)
1992-93 (N) 10S (2.0) 80S (56.6) 15S (4.8) l00S (49.0)
(A) 40S (19.9) l00S (72.9) 20 MS (3.8) 80S (67.4)
__________________________________________________________________
Table 7. Reaction to brown and stem rusts in the Peninsular Zone.
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Year DL 802-3 Sonalika HD 2501 HI 977
__________________________________________________________________
Brown rust
1991-92 (N) 5 MR (0.7) 100S (65.0) 5 MR (0.7) 20S (11.3)
(A) TMR (0.1) 80S (50.2) 40S (12.3)
50S (16.6)
1992-93 (N) 0 70S (35.8) 40S (20.2) 50S (16.6)
(A) 20S (3.7) 80S (57.5) 40S (19.0)
100S (55.0)
1993-94 (N) 50S (36.0) 50S (40.2) 20S (-) 50S (-)
(A) 40S (16.2) 80S (73.3) 20S (11.4)
80S (31.0)
Black rust
1991-92 (N) 20S 40S l0S 5S
(A) l0S (4.69) 40S (23.4) 5S (1.6)
30S* (6.9)
1992-93 (N) 60 MR 80S l0 MR 40 MS
(A) 40S (15.0) 60S (29.7) 60S* (11.6)
100S (26.7)
1993-94 (N) 60S* 20 MS 60 MS 30S
(A) 40 MS (16.6) 60S (36.5) 5 MR (1.0) 60S (35.0)
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* Highest score at one location only.
Table 8. Adult plant response pattern of DL 802-3, compared to the popular checks,
against selected pathotypes of brown rust.
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77-1 77-5
________________________ ________________________
Genotype D U L D U L
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DL 802-3 l0 MS 0 ;l l0 MR-MS 0 ;l
Sonalika 60S 80S 33+ 70S 50S 33+
HS 2285 40S 90S ; 70S 90S 33+
PBW 226 TMS - ; l0S - ;
HD 2501 TR 30S ; 20 MR-80S 70S 1+2-
HI 977 5 MS 60S ; 20S 60S ;
HD 2610 l0S 0 ; 40 MR-MS 0 3
HP 1209 TMR 0 ;l 20S 0 ;
HUW 234 40S 60S 3 80S 90S 33+
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D = Delhi; U = Uchani; L = Ludhiana.
Stem rust and yellow rust resistance.
DL 802-3 has been postulated to carry Sr31, which
is a highly effective gene, worldwide, for stem rust and recommended
for durable resistance to stem rust. Yrl8, a partially
effective gene for adult plant stripe rust resistance, has been
shown to provide a durable and high level of resistance to stripe
rust in combination with Yr9, another highly effective
gene to stripe rust in the subcontinent.
The genotype was included in the Elite
Plant Pathological Screening Nursery (Elite PPSN) based on multilocation,
consecutive tests for 3 years: 1991-92,
leaf and stem rusts; 1992-93,
leaf and stripe rusts; and 1993-94,
leaf and stripe rusts; because it has been established as resistant
to different rusts (ACI 0 to 10.0).
The genotype has an ideal plant height
of 89 cm and matures in 122 days. The grains are amber white
and semihard and have a 1,000 kernel weight of 38 g.
Slow-rusting studies.
Slow-rusting studies were initiated in a glasshouse for standardizing
the technique using an endogenously developed inoculation tower
and the known slow-rusters Mango, Trap, Parula, and Chris and
the fast-rusters Agra Local and Kharchia Local. DL 802-3
also was included to clarify the role of slow-rusting resistance
in this genotype. Initial results are encouraging.
Indian Agricultural Research Institute
Nuclear Research Laboratory1 and
Division of Genetics2, New Delhi, 110 012, India.
P.N. Tiwari1, P.N. Gambhir1, S. Nagarajan1, P.S.L. Srivastava2, and S.R. Singh2.