GLOBAL THREATS TO CEREAL –A
HABIB-UR-REHMAN 14-ARID-3041 SAHIL
SHERAZ AHMAD 14 ARID 3395
Institute of Food and Nutritional
Science PMAS Arid Agriculture University Rawalpindi
GLOBAL THREATS TO CEREAL
HABIB-UR-REHMAN, SAHIL NAZIR
Institute of Food and Nutritional Science PMAS Arid
Agriculture University Rawalpindi.
Cereals are considered as the basic source of food and feed
for both human and animals respectively. Climatic factors like temperature ,
moisture , rainfall , moisture and drought conditions can adversely effect the
cereal crop yield. Different pathological factors and pests are also important
threats for cereal crops. Crops are dependent on climatic conditions that’s why
their yield and their physiological characters are effected. The rapid increase
of the carbon di-oxide concentration in the atmosphere and related expected
rise of temperature can effect the functioning of ecosystems in future. Various
plants physiological processes are affected by climate change. The yield of
wheat , oat , barley and triticate is badly affected by bymoviruses and
furoviruses. These viruses and other pathogens are of great importance in wheat
growing areas. Temperature and relative humidity and wind velocity interact in
nature and contribute collectively in making the environment favourable for the
disease development. However, all factors combine togather and cause different
diseases to cereal crops that can reduce yield.
Climate , Temperature ,Moisture, Diseases , Pests ,
The rapid increase of the carbon di-oxide concentration in
the atmosphere and related expected rise of temperature can effect the
functioning of ecosystems in future. Various plants physiological processes are
affected by climate change. CO2 increase stimulates photosynthesis and effects
stmatal conductance(Lemon 1983;cureand Acock 1986) and use of water
effeciancy(Gifford,1979). Africa is
directed to climate change due to its long term dependence on rainfed
agriculture(Belay,2013). Small holder farmers are specifically exposed to
changes that badly effect their climate dependent
livelihoods(Ngigi,2009).Small-holder farming is affected by current climate
changes and will be more threatened by on going climate changes(Boko et
al.,2007). Same as African countries ,Ethiopia also mainly dependent on
agriculture, which help 50 percent to the national GDP, supplies 73 percent of
the raw materials to agro industries and generates 88 percent of the expert
earnings(Derssa and Hassan,2009).Ethiopian agriculture is characterized by a
less use of external inputs and is highly exposed to climate changes(Demeke et
al.,2011). As like climate change ,Some diseases are also threat for Cereal
crops. Stripe rust(Yellow rust), caused
by Puccinia striiformis west, is a dangerous but sporadic disease of warm
areas.(Colin,2010). Small grain cereals
, like wheat and barley are of outstanding importance of crop
production. These crops are effected by diseases and affected by different kind
of pests(Adams et al.,1988). The kernel bunt caused by Neovossia indica(Mitra)
Mundkur(Mund-kur, 1940) was reported by Mitra in 1931 from kernel. It is
another threat for cereal crops. Septoria disease is another threat for wheat
crop that was firstly reported in England and it is the risk factor for wheat
crop and it causes loss in yield(Barkeley ,1988).
Soil borne viruses-a threat
to cereal crops
A number of
furo and bymo-viruses that are naturally transmitted by the ubiquitous soil
borne protozoon polymyxa garminix are
of great importance for wheat , oat , barley and triticate. The yield of wheat
, oat , barley and triticate is badly affected by bymoviruses and furoviruses.
These viruses and other pathogens are of great importance in wheat growing
areas.(Thomas,2009).Small grain cereals like Wheat and barley are and other
cereal crops are attacked by viruses and numerous pests whickh causes many
diseases. (Table 1 ). In natural environment all viruses are transmitted to their host plant
by root inhabiting fungal like plasmodiophorid , polymyxa graminis.(Adams et al.,1988). This microorganism is
worldwide in distribution and multiplies in roots of grass and cereal species.
provides protection to viruses against unfavourable conditions and crop
rotation situation and allow virues to persist for long time.(Adams et
al.,1993).If the conditions are suitable and soil moisture is present then
these viruses release zoospores which move actively towards host and enter root
hairs cell.If the plant is affected then P.graminis
acquires the viruses inside the cells(Camobell,1996).
soil borne viruses of cereals.
Natural host species
B T R
Barley yellow mosaic virus
Barley mild mosaic virus
Soil-borne wheat mosaic virus
X X X
Soil-borne cereal mosaic virus
X X X
Chinese wheat mosaic virus
Wheat spindle streak mosaic virus
X X X
Wheat yellow mosaic virus
Oat golden stripe virus
Oat mosaic virus
,B=Barley , T=Triticate , O=Oat , R=Rye
Effect of weed on yield of Cereal crops.
aestivum L.) is the first and most important staple food in Pakistan and is
adapted to wide range of soil and climate conditions. Wheat plays a vital role in
Pakistan economic life. It is grown on an area of 8.3 million hectares with a
total production of 18.34 million tones in the world with average yield of 2166
kg/ha (Govt of Pak. 1999) Pakistan is ranked 9 in wheat production. The average
yield of wheat in Pakistan is very low as compared to other wheat growing
countries of the world. Low yield per
hectare ,besides many other factors, may be attributed to serious weed
Weeds lower crop productivity through their competition with
crop plants for nutrients, water, space, light and CO2.Weeds decrease yield by
15-50 % and in serious cases may lead to the complete failure of crop (Gill and
Walia, 1979). Besides their direct effect on crop, weeds also lower the market
value of the produce and hence bring enormous economic losses to growers.
of climate change on productivity of cereals
The promt increase of the carbon di-oxide concentration in
the atmosphere and the related projected rise of temperature may affect the
functioning of ecosystems in future. Various plant physiological processes are
affected by climatic variations. CO2 increase stimulates photosynthesis and
effect stumatal conductance(Lemon 1983) & Acock 1986) and water use efficiency
(Gifford 1979). Field conditions varies in time and space , interactions with
other environment factors occur, and species can vary in their response to CO2
concentration(Sage et al., 1989). Positive effect of CO2 and can compensate the
negative effect of temperature(Kimball
Impact of moisture and temperature on the yield and quality
of wheat cultivars.
Major step that decrease crop yield in the world is drought
reported by (Bruce et al,2002).The combined effects of drought and high
temperature on the overall yield is higher that the individual effects (Sharma and Kaurr, 2009, Grigorova et al., 2011).Martell
(2011) stated that Southern Europe Russia is the major wheat producing
region, in this area temperature and moisture stress cause premature ripening
of grain that cause significant reduce in yield. Wang
(2005) observed that moisture stress cause decrease in the
photosynthesis and accelerated leaf senescence that cause reduction in the
Temperature and relative humidity and wind velocity interact
in nature and contribute collectively in making the environment favourable for
the disease development. However, all factors combine togather and cause
different diseases to cereal crops that can reduce yield.
Water stress under rainfed conditions significantly reduce
wheat grain yield (Hossain et al, 2012). Climate change cause changing in
global rainfall patterns and increase in temperature influence the crop growth
and yield Hasan-uz-Zaman et al, (2012).Hakim et al, (2012) reported that
optimum temperature 20-25 C for spring wheat growth and yield. Changes in evapo
transportation rate depend upon the availability of moisture at the onset of a
drought and the severity and duration of a drought (Hanson,2003, Hossain et al,
2012, Siapoosh et al., 2011).
Weather parameters during wheat growing season 2014-2015 at
university Research Farm
November-30th November 2014
December-31st December 2014
January-31st January 2015
February -28th February 2015
March-31st March 2015
April-20th April 2015
Climate variability is a concern and researchers are engaged
in understanding its impact on growth and yield of crops and also identifying
suitable management options to sustain the crops productivity under the rainfed ecology.
Climate variability may lead to prolonged dry spells or more intensified heat
waves seriously impairing agricultural productivity(hassan et al.,2013)
Stripe rust impact on wheat crop
Productivity with high yield is dependent upon resistances or
tolerances in crop varieties. Thrust diseases of wheat have historically been
one of major biotic production constraints both in Pakistan and rest of the
world , in spite of enormous progress made iin their control in many countries
. Stem rust , Leaf rust and stripe rust comtinue to pose a major threat to
eheat production over a large area.(singh and Hassan , 2000).
Of the three rusts diseases of bread wheat , stripe rust is
most damaging to grain yields(Singh et al.,2000). Out of then total 8.803
million of wheat production area in Pakistan , 70 percent is prone to stripe
rust , which encompasses an area of about 5.8 million hactares. In Pakistan ,
the rust epidemics have occurred in 1947-1948.(Hassan et al.,1979).
Stripe rust of wheat caused by puccinia striiformis f. a fungus belongs to order uredinals of
class Basidiomycetes is one of the most important diseases of wheat and its
distribution around the world were given by Hassebrauk(1965). Stripe rust of
wheat have been reported in more than 60 countries and on all continents excepts
Antarctica.(Gadd , 1777).
Stripe rust cause 100 percent yield loss if infection occurs
very early and the diseases continues to develop during the growing season
provided the cultivars are susceptible. In most wheat producing areas , yield
losses caused by stripe rust have ranged from 10-70 percent depending upon the
susceptibility of cultivars , earliness of initial infection , rate of disease
development and duration of the disease(Chen,2005).
Resistance to yellow rust My be based on genes which are
expressed at all growth stages of the plant , or genes which are effective
mainly at the post seedling and adult plant stages where the level of
resistance increases as the plant matures(Johnson and Taylor,1972).
Most stripe rust resistance genes have been mapped using
aneuploidy stocks(Mclntosh et al.,1995). But some was recently molecularly
tagged. Depending upon the closeness of markers should be useful in marker
assisted selection.(yen et al.,2003).
GENOME BASED SH
infection Type against yellow rust inoculums at CDRP sunny Bank Screen house Murree
screening Results to yellow rust inoculum
S =Susceptible , —–= missing entries
Drought conditions in Pakistan and
impact on cereal yield.
In Pakistan drought and high temperature can occur during
seedling emergence of wheat as well as grain filling stage. These stresses can
badly effect the seedling emergence , coleoptile length , seedling growth and
photosynthesis in wheat and other cereals crops. Drought effects morphological
, physiological , biochemical and molecular processes in plants resulting in
growth inhibition , stomatal closure with consecutive reduction of transpiration
, decrease in chlorophyll content and inhibition of photosynthesis and protein
changes(Demirevska , 2008). The world wide water shortage and un even
distribution of rainfall makes the improvement of drought resistance especially
important. Fulfillment of this gaol would be enhanced by an understanding of
the genetic and molecular basis of drought resistance(Bing et al.,2006).
Drought stress is a major limitation to bread wheat productivity and its yield
stability in arid and semi arid regions of the world including parts of
Pakistan. It has been estimated that about one third of the world’s potentially
viable land suffers from an insufficient supply of water and crop yield are
periodically reduced by droght(Khan et al.,2007).
Drought is actually a meteorological event which implies the
absence of rainfall for a period of time
, long enough to cause mosture depletion in the soil and in water potential of
plant tissues. But from agricultural point of view, its working definition
would be inadequacy of water availability
, including precipitation and soil-moisture capacity , in quantity and
distribution during the life cycle of a crop plant , which restricts the
expression of full genetic potential of the plant(Jiban, 2001).
There are some varities of wheat that are resistance to
Drought resistance index value
Name of varieties
Drought is a big problem for developing countries like
Pakistan , hindering the wheat production drastically.
Impact of SITOTROGA CEREALELLA on the viability of wheat seed.
A number of insect pests are responsible for the damage of
stored wheat grains like Rice weevil, lesser grain borer , Red flour beetle and
Angumois grain moth.(Omer and Kamel,1984). These species damage the wheat and
about 2-6 percent food grain production is lost every year during storage by
stored grain insect pests. About 10-15 percent wheat is lost annually due to
ravages of stored grain insect pests during storage(Department of plant protection,1986).
Khan et al.,(1985) investigated the storage losses to wheat
in tehsil Faisalabad during a 10 months storage period in private and public sector and public sector dodowns
and found it to be 2.5 and 0.74 percent, respectively , resulting in overall
losses to wheat by insect pests during storage period from june to January.
All stored grain insects posses the phenomenon of preference
for then grains of various crops varirties. This situation helps the plant
breeders to develop new varieties. This situation helps the plant breaders to
develop new varities which are less susceptible to attack of pests.(Sarin and
Hatchability percentage of S. cerealella in different wheat
IMPACT OF CEREAL APHID ON WHEAT
Wheat is severely attacked by the wheat aphids which affect
the produce adversely (Grigorove,1976,).Greenbug,S GRAMINUM (Rondani) is
monoecious and exhibits life cycle on Graminae(Blackman and Eastop, 1984). This is prominent aphid species
attacking in Pakistan.Bird cherry oat aphid,R. padi (Linnaeus) is heteroecious
migrating between its primary host,the Bird cherry,prunus padus and its
Graminaceious host and exhibit holocyclic life cycle between
them(Naeem,1996).Corn leaf aphid can be found on corn,sorghum,wheat and barley.
English Grain Aphid can be found on corn , sorghum , wheat and barley. And they
are the emerging threat for cereal crops that reduce grain yield.(fitch,1993).
Several control methods have been used to prevent losses by
Aphid. Host plant resistancenis an important part of IPM of aphids. Partial
resistance could well provide adequate
control of aphids with only cultural practices and occcasionaluse of
pesticide on out breaks.(Sattar et al.,2001).
Abiotic factors affect the physiology and behavior of insects
and acts as density independent factors which only determine the change in
insect population.abiotic factors can produce physiological effects on insect
population in four different ways by modifying activity of endocrine system ,
survival , development and reproduction(Varley et al.,1973).
Archer et al.,(1988)
observed wheat response to Russian wheat aphid infestation varied at different
growth stages and determined the effects of wheat growth stages.
Correlation between Cereal aphid and population and
agronomical characters of wheat varities.
Rhopalosiphum Padi Correlation
Schizaphis graminum Correlation
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