8th INTERNATIONAL WHEAT CONFERENCE

INfLueNCe of TeRmINAL dRoughT STReSS oN WheAT
AgRoNomIC TRAITS, INduSTRIAL quALITy
ANd dehydRIN PRoTeINS
1, Marina Castro, 1 Daniel Vázquez,
1 Jarislav von Zitzewitz and 1 Bettina Lado
1 National Agricultural Research Institute (INIA), Ruta 50 km 11, Colonia 70000, Uruguay.
E-mail Address of presenting author: mcastro@inia.org.uy
Wheat (Triticum aestivum L.) exposed to water deficit during grain filling show altered
agronomic and grain quality characteristics. Drought causes yield losses and seasonal variation
in quality creating difficulties in the marketing and processing of grain. Therefore,
improving the genetic adaptation of wheat cultivars to drought stress is an important objective
in breeding programs. There are genotypes that have been reported to have tolerant
response and could be used as genetic sources for drought tolerance. There is interest in
identifying molecular markers associated with drought tolerance to apply future genomic
selection strategies, and thus make the breeding process more efficient. Five spring wheat
cultivars (BIOINTA 1001, BRS 208, INIA CHURRINCHE, ITAPUA 50, PANDORA INIA)
from Argentina, Brazil, Uruguay, Paraguay, and Chile respectively, and two checks (TOL-
LACAN and a Synthetic wheat, from CIMMYT) were evaluated in Uruguay in controlled
environments. The experiment was conducted in a split-plot design with two cycles of
progressive drought stress during grain filling. At maturity, grain yield (Y), kernel number
(KN), thousand kernel weight (TKW), aerial biomass (BIOM), root width (RWidth), root
length (RLength), root weight (RWgth), and harvest index (HI) were determined. Additionally,
grain protein content (Pt) was determined by NIRs, and rheological dough properties
were evaluated by 10 g mixograph. To asses dehydrin expression, flag leaves tissue samples
were collected during the drought cycles, and stored at -80ºC. Agronomic traits as KN
and BIOM decreased with drought stress. Significant genotype x treatment interaction was
detected for Y, TKW, and RWidth. No significant effect of drought stress was detected for
RLength or RWght. Rheological properties were affected by drought stress increasing mixogram
maximum height at peak (MHP) and mixogram time to maximum height (TMH).
Significant genotype x treatment interaction was found for grain protein concentration,
MHP and TMH. BIOINTA 1001 was the genotype that showed more instability, and BRS
208 was the genotype with fewer changes due to drought stress in the variables under consideration.
In this study, cultivars with relatively stable agronomic and quality characteristics
under drought stress were found, which could be used as genetic sources for resistance.
The correlation of dehydrin transcription and protein accumulation with drought tolerance
is being studied as an indicator for association mapping studies and selection strategies.
Acknowledgments
The project was funded by PROCISUR and INIA (Uruguay). Authors are thankful to
wheat breeders from Argentina, Brazil, Chile, Mexico, Paraguay and Uruguay for selecting
and providing genotypes for this study.
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