Centre for Plant & Water Science - Central Queensland University

Centre for Plant & Water Science 2008 Annual Report
carried out as in the Drought pool experiment. Root length density distribution and root phenotyping
was also conducted for each accession.
Tomato accessions tested in terminal drought experiment, and approach for root recovering for
phenotyping and RLD mapping.
The results of the terminal drought experiment suggested that the wild tomato accessions L3708 and
LA1579 (S. pimpinellifollium) and LA1940 (S. pennellii) had highest root length density and greatest
root penetration compared to all other tested accessions (Figure 4). Delayed symptoms of permanent
wilting noted in this experiment as well as in the drought pool experiment may well be associated
with greater root foraging for soil water in these wild tomato accession under declining soil moisture
regimes.
Experimental approach 3 – Deficit irrigation
In the deficit irrigation experiment each accession was planted (18 July 2008) in individual bucket
containers (20 L, 25 cm diameter x 45 cm height) containing 27 kg of soil maintained at two
different soil moisture levels [(field capacity and deficit irrigation (50% of FC)], replicated twice in a
randomised fashion with daily irrigation supplied to maintain each treatment (Figure 5). Daily
evapotranspiration requirements of each accession, crop water use, water use efficiency, stomatal
frequency, distribution and sizing were studied in this trial, and measurements for soil moisture,
physiological, morphological, growth and development traits and yields were assessed at monthly
intervals.
Under deficit irrigation the wild tomato accessions L3708 and LA1579 (S. pimpinellifollium) and
LA1940 (S. pennellii) transpired least amount (20-45% of Arka Meghali) compared to all other
accessions. However, the dry biomass production by these accessions under deficit irrigation was
comparable to those highest transpiring accession such as Arka Meghali.
Drought tolerant wild accessions showed sustained growth, slow development of drought symptoms,
and were capable of producing flowers, fruits and completion of full life cycle under declining soil
moisture conditions similar to terminal drought in field environments. It appears that root traits and
leaf osmotic adjustment play key role on conferring drought tolerance in these accessions. However,
their fruit quality was extremely poor and these plants have viny growth habit with profuse flowering
and fruiting. However, they show promise for utilization of their candidate drought tolerant genes for
crossing with appropriate cultivated tomato. Further research is required for detailed phenotying of
drought tolerant traits and confirm these preliminary findings.
Project Staff Dr Surya P Bhattarai Prof David Midmore
Dr Robert de la Pena
Dr Sanjay Singh
Laurie Tait
Delphine Lacombe
Funding
AVRDC, the World Vegetable Centre, Taiwan & CQUniversity
Income
$29,985.00 AUD and $33,000.00 USD
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