Semelhante a Sess08 3 agili in vitro evaluation of orange-fleshed sweetpotato (ipomoea batatas lam) genotypes for drought tolerance using polyethylene glycol
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Semelhante a Sess08 3 agili in vitro evaluation of orange-fleshed sweetpotato (ipomoea batatas lam) genotypes for drought tolerance using polyethylene glycol (20)
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Sess08 3 agili in vitro evaluation of orange-fleshed sweetpotato (ipomoea batatas lam) genotypes for drought tolerance using polyethylene glycol
1. In vitro evaluation of
Orange-Fleshed
Sweetpotato (Ipomoea
batatas Lam) genotypes for
drought tolerance using
polyethylene glycol
Agili, Sammy, Nyende B, Ngamau K,Masinde
P
30th June to 4th July 2013
9th Triennial Conference of APA, Naivasha, Kenya
3. Importance of Sweetpotato
Rank 7th among food crops of the world
(CIP, 1997); Area under cultivation world
wide is 9M hectares
95% of the world’s sweetpotato output is
from developing countries
Predominantly grown in small plots by
poor farmers, hence known as poor man’s
crop
4. Importance of Sweetpotato
Major source of food/nutrition
Ability to produce under adverse weather
conditions
Short maturity period/possible to have two
crops in a year
OFSP types-contains sufficient levels of beta
carotene
5. Importance of Drought in Sweetpotato
production
Drought is often a major environmental
constraint for sweet potato production in areas
where it is grown under rain fed conditions
Under field conditions drought severity, timing
and duration vary from year to year and a
cultivar which is successful in one year might
fail in another year
6. Importance of drought in
sweetpotato production, cont.
The unpredictable and variable forms in
which drought manifest complicates the
selection of superior plant materials as well
as breeding programs
7. In vitro culture technique for drought screening
• In vitro culture techniques minimizes
environmental variations due to defined nutrient
media, controlled conditions and homogeneity
of stress application; can handle a large
number of materials
• Osmotica/ PEG6000- stimulate water deficit
conditions in cultured cells in a manner similar
to that observed in the cells of intact plants
subjected to true drought conditions
8. The technique has been used for various crops
Wheat genotypes (Hsissou and
Bouharmont,1994)
Tomatoes(Manoj and Uday,2007)
Rice(Shankhodhar et al 2000)
Green grams(Gulati and Jaiwal, 1993)
In vitro screening, cont.
9. To Screen a large number of orange-fleshed
sweetpotato genotypes at earlier stages of
development for drought tolerance under in vitro
conditions simulating stress drought conditions
Place-Tissue culture laboratory, Kenya plant
Health Inspectorate Service Quarantine station,
Muguga, Kenya
Objective of the study
10. Genetic material
Consisted of 59 OFSP genotypes with
contrasting beta carotene and mineral content
levels received from CIP, Lima
For initial propagation the materials were
transferred into in vitro and routinely propagated
from the nodal cutting(0.2-0.5cm), each circle
lasting 2-4 weeks.
11. Planting material/preparation of growth
media
Propagation of planting material for the 59 genotypes
were from nodal done in MS media
MS basal media containing 30g/l sucrose and 2.8g/l
phytogel maintained at PH 5.7 + PEG (6000) at 0,10 and
15g/l was used as the growth media
5cuttings with2-3nodes/kilner jar/genotype/
Factorial/CRBD/ two factor factorial design with 3
replications
Growth condition-10 hours per day; photon light flux
density of 70µmol m²/s, 28ºC for 65 days
12. Data gathered
Root length (cm)
Root dry weight (g)-dried
for 48h at 65ºC
Leaf Area (cm²)
Shoot length (cm)
Shoot fresh weight (g)
Shoot dry weight (g)-
dried for 48h at 65ºC
Data analysis-SAS
version 8
14. ANOVA
Analysis of variance indicated genotypes,
salt levels and salt level x genotype
interaction, were highly significant (p<0.001)
with respect to all the traits
This shows the presence of variability,
different responses to genotypes to different
salt levels
20. Conclusions
10 genotypes were identified as drought
tolerant:194515.5, 194539.36, 441724, 441538,
189135.9, 401055, 441768,192033.5, 440027 and
440429. All showed higher leaf expansion, higher
stem length elongation, high root and shoot growth
and high dry matter production at high salt
concentration level
Correct/clear expression of genotypes can be
evaluated by this method using different PEG
concentrations
21. Conclusions
In vitro screening method using PEG (6000) was
found to be a simple enough to be used for evaluation
of drought tolerance in a large number of genotypes
in very short time.
Out of the 10 genotypes identified as drought tolerant
under in vitro screening 5 were confirmed to be
tolerant under field conditions suggesting that in vitro
screening can be a simple method of evaluating
OFSP genotypes drought tolerance