Maize Genetics Cooperation Newsletter vol 86 2012
Screening of Extra Early Maize Inbred
under artificial epiphytotic condition for North-Western Himalayan region of
India
Chandrashekara, C*., Jha, S. K., Agrawal, P. K., Singh, N.K. and Bhatt, J.
C.
Vivekananda Parvatiya Krishi Anusandhan Sansthan,
(ICAR), Almora (Uttarakhand), India
Abstract
A field study was conducted to identify the sources of resistance against turcicum leaf blight (TLB) in maize. Thirty
five inbreds were evaluated under artificial
epiphytotic conditions at Hawalbagh, Almora (1250 m above mean sea level altitude) and a hot
spot location for TLB in India. Out of these 35 inbreds,
10 entries were found resistant, 18 were moderately resistant, 3 were susceptible and 4 were highly Susceptible to the TLB. The inbred lines viz., V373, V398, V407, V418, VQL2 and
CM 145 showed high degree of resistance to both TLB and Maydis
Leaf Blight (MLB) where as V351, V414, VQL1 and CM212 were found to be highly susceptible.
Introduction
Maize (Zea mays L.) is one of the
most important cereals in the world due to its high yield potential and great
demand as food, feed and industrial purpose. The area, production and
productivity of maize have increased significantly in last few decades. However,
at one or other point of time, the sustainability of the maize production to
meet the futuristic demand is remains to be debatable due to existing biotic
and abiotic stresses as well as unexpected outcome of the global phenomenon of
climate change. Indian Himalayan states have been centre
of maize cultivation since long back and contributing significantly to maize
production as well demand. Due to relatively low temperature and high humidity
during the maize growing season, Turcicum leaf blight
(TLB) and Maydis Leaf blight (MLB) are the two major
diseases remains to be problematic to highland maize farmers in
Himalayan region.
The turcicum leaf blight of maize (syn. Northern
leaf blight) incited by the fungus Exserohilum
turcicum (Pass.) Leonard and Sugs.
[(Synonyms; Drechslera turcica
(Pass.), Shoemaker. Helminthosporium turcicum (Pass.)] is an
important foliar disease of maize worldwide. In India, this disease is
prevalent in the states of Karnataka, Himachal Pradesh, Uttarakhand,
Orissa, Andhra Pradesh and North Eastern Hill states. It also affects the Rabi maize in the plains of India. Turcicum leaf blight is the endemic in maize growing areas
of the North Western Himalayan regions and considered to be very important in
terms of its geographical distribution and potential to cause yield losses. TLB
can be severe in mid-altitude tropical regions where high humidity, low
temperature, and cloudy weather prevail during the maize growing season (Singh,
2004). Yield losses can easily exceed 50% if the disease appears before
flowering (Raymundo et al., 1981; Tefferi et al., 1996). However the losses get
reduced if the infection takes place at a later stage. The Genetics of
resistance is determined in most of maize genotypes quantitatively and has been
used for control of this disease (Sangit Kumar et al,
2011). Resistance was partially dominant
and controlled by many genes (Van der Plank 1968; Caldwell 1968; Nelson 1973). The
present study was carried out to identify sources of resistant against TLB prevalent
in the North-Western Hill regions of India.
MATERIALS AND
METHODS
Field screening against TLB was carried at the Hawalbagh
Research farm (29� 38� 3�� N and 79� 37� 49�� E), Almora,
Uttarakhand, which is one of the hot spot for Turcicum leaf blight in India. The experiments were
conducted to identify new sources of resistance. Thirty five
inbred lines developed at VPKAS, Almora were
evaluated during Kharif
2010 (wet season) in randomized block design with two replications, under
artificial epiphytotic condition. Each test line was sown in three rows of 3 m
and rows were spaced at 60 cm. Spreader rows of highly susceptible local inbred
V351 were planted at regular intervals as a source of secondary inoculum for the
disease development. The recommended package of practices was followed during
crop growth.
The inoculum of Exserohilum turcicum prevalent in North Western Himalayas was prepared
by growing the fungal mycelium on sorghum grains. After proper fungal growth
(after seven days), the grains were dried under the shade at room temperature.
A fine powder of these grains was prepared with the help of a
mixer–grinder. For the creation of proper disease pressure, a pinch of
this powder was put in the leaf whorl of each plant. Each plot was inoculated with
a conidial suspension at the 4-5 leaf stage, followed
by three more inoculations at 7-8 days intervals. Even if there was frequent
rainfall during the crop season, still the crop experienced intermittent short
dry spells. Hence the plots were irrigated by knapsack
sprayer to maintain the relative humidity of more than 80%. The disease
first gets manifested after 8-12 days of inoculation among different test
materials. The disease appeared in infector rows earlier and became severe by
the time of silking. The disease severity was
recorded after two weeks of inoculation. Genotypes were screened under
arti�cial epiphytotic conditions in a scale of 0–5 rating as per CIMMYT
protocol (CIMMYT, 1985; Singh et
al. 2004).
RESULTS AND
DISCUSSION
A total of 35 maize inbred lines along with resistant and susceptible checks were screened for TLB. On the basis of disease reaction and rating scale, the performance of all the maize inbred lines was classified into four groups: a score of 1-2 was considered resistant, >2.5-3.5 was moderately resistant, >4.0 was susceptible, and >4.5 was highly susceptible (Table 1).
Table 1. Classification of 35 maize inbred lines based
disease reaction and rating scale
|
Reaction |
Inbred line |
|
Resistant |
V336, V346,V373, V398, V400, V401, V407, V418, VQL2, CM145 |
|
Moderately Resistant |
V152, V334, V335, V338, V340, V341, V345, V372, V383, V390, V403, V404, V405, V409, V410, VQL17, CM141, CM153 |
|
Susceptible |
V25, V402, V406 |
|
Highly susceptible |
V351, V414, CM212, VQL1 |
The present study resulted in identification of 10 resistant inbred lines. Among them V373, V398, V407, V418, VQL2 CM 145 were with least disease incidence for not only to TLB but also to other diseases, including maydis leaf blight. About 18 inbred lines were observed to be moderately resistant to TLB. In general, resistant and moderately resistant test materials were greater in number than susceptible and highly susceptible types. The new sources of TLB resistance identified in the present study will be helpful for their deployment in breeding program and as donors for different basic and applied research.
References:
Caldwell, R.M. (1968). Breeding for general and specific
plant disease resistance. Proc. 3rd Int.Wheat
Genetic Symp. 1968, p. 263–272.
CIMMYT. (1985). Managing trials and reporting data for
CIMMYT�s international maize testing program. Mexico (DF): CIMMYT.
Nelson, R.R. (1973). Breeding plants for disease
resistance. Unipark (PA): State University Press. p.
401.
Rajesh Singh,
Mani, V.P., Koranga, K.S., Bisht,
G.S., Khandelwal, R.S., Bhandari,
P. and Pant, S.K. (2004). Identification of additional sources of resistance to
exserohilum turcicum in maize (Zea maysl.). SABRAO Journal of
Breeding and Genetics. 36(1) 45-47, 2004.
Raymundo, A. D., Perkins,
J.M. and Hooker. A.L. (1981). Effect
of gene HtN on the development of Northern
corn leaf blight epidemics. Plant Dis. 65: 327-330.
Sangit Kumar, Pardurange Gowd, K.T. Pant, S.K., Meena Shekhar, Bupesh Kumar, Bineet Kaur, Hettiara
Chchi, K., Singh, O.N. and. Parsanna,
B.H. (2011). Sources of resistance to Exserohilum turcicum (Pass.) and Puccinia polysora (Underw.) incitant
of Turcicum leaf blight and polysora
rust of maize. Arch. of Phytopath. and Pl. Protect. 44: 528–536.
Tefferi, A.,M. Hulluka, and H.G. Welz. (1996). Evaluation of maize germplasm for resistance to turcicum
leaf blight in Bako area. Western Ethiopia. African
J. Plant Prot. 6: 75-82.
Van der Plank, J.E. (1968). Disease
resistance in plants. New York and London: Academic Press.
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Newsletter may be cited only with consent of authors.