ICRISAT Archival Report 2006 - The seedlings of success in the ...

TSV infection was recorded both on inoculated and subsequently emerged leaflets based on visual symptoms and by
enzyme-linked immunosorbent assay (ELISA). Systemic virus infection in the test accessions ranged between 0 and
100%. Twenty-four of these accessions in section Arachis that had 0 to 35% systemically infected plants were retested,
and eight of these accessions did not show systemic infection in repeated trials in the greenhouse. These were
ICG 8139, ICG 8195, ICG 8200, ICG 8203, ICG 8205, and ICG 11550 (A. duranensis), ICG 8144 (A. villosa), and
ICG 13210 (A. stenosperma). Although, these accessions showed TSV infection in inoculated leaves ranging
between 0 and 100%, the virus was not detected in the subsequently emerged leaves, indicating block in systemic
spread of virus amounting to the disease resistance. The eight TSV resistant accessions are cross compatible with A.
hypogaea for utilization in breeding for stem necrosis disease resistance. The resistant accessions, ICG 8139 and
ICG 11550 also possess high levels of resistance to rust (P. arachidis) and late leaf spot (P. personata), and ICG
8144 to Peanut bud necrosis virus, and thus have multiple resistance to virus and pathogens, and can be used to
develop multiple disease resistant peanut varieties through inter-specific breeding.
Lava Kumar, Farid Waliyar, SN Nigam and R Aruna
Milestone: 50 lines of advanced generation interspecific derivatives of groundnut evaluated for LLS disease and
promising lines identified (FW/NM/PLK) 2008
Screening of advanced interspecific derivatives against late leaf spot resistance: About 84 selections from 4
wide crosses (Arachis kempf-mercadoi, A. glabrata, A. batizocoi, and A. duranensis) were screened for resistance to
late leaf spot (LLS) under field conditions during 2006 rainy season. Field trials were laid out in a broad-bed-andfurrow
(BBF) system with three replications. The size of each plot was 1.5 x 4 m, with inter-row spacing of 30 cm,
and plant to plant spacing of 10 cm. TMV 2, a highly susceptible cultivar to LLS was used as an infector row after
every five-test rows. Chemical sprays were used to control insect pests. At 45 days after sowing, plots were
inoculated by spraying the conidial suspension of P. personata urediniospores. After inoculation, perfo-irrigation
was provided daily for 30 min in the evening for 30 days to create high humidity required for disease development.
The LLS incidence and severity was scored on a 1 - 9 rating scale at 91 and 106 days after sowing. The development
of LLS was uniform throughout the infector rows. Among the test lines, highly significant differences were
observed and coefficient of variation was in the range of 14.4 to 15.1%. Out of 84 interspecific derivatives, twentytwo
lines from A. hypogaea X A. cardenasii showed high level of resistance to LLS with a score of 2, Fifty-one lines
had a score of 2 to 3, nine had a score of 3 to 4, and the remaining two lines were rated >5 at 106 days after sowing
(Fig. 3). The disease severity in the susceptible check was 9.0. Promising lines with a disease rating of 3 and less
will be advanced.
Disease score (1-9) scale
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
18-1
4366-3
4367-1
4367-6
4368-5
4371-2
4531-1
4531-4
4367-5
4368-8
4531-11
4531-3
4531-7
18-13
3657-1
4367-8
4369-5
4531-15
18-4
3664-1
4364-4
4373-15
4373-6
4374-6
CS26-CS5-2
38-4
2926-1
2928-
Progenies
Fig. 3. Screening of advanced interspecific derivatives against late leaf spot at 106 days after crop emergence
(ICRISAT, Patancheru, 2006 rainy season).
Farid Waliyar, Lava Kumar and Nalini Mallikarjuna
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