RELEVANCE OF ROOT CHARACTERISTICS IN IMPROVING DROUGHT ADAPTATION IN TOMATO
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Date
2019-11-30
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UNIVERSITY OF AGRICULTURAL SCIENCES GKVK, BENGALURU
Abstract
Due to limited availability of aerable land and the high market demand for
vegetables around the world, solanaceous crops are cultivated under unfavorable
environmental conditions leading to reduced quality and productivity of crops. One way
to reduce losses in productivity of vegetable crops would be to graft them onto rootstocks
capable of reducing the effect of external stresses on the shoot. In order to achieve this,
identification of suitable root stock having superior root characteristics with higher level
of root intrinsic cellular level tolerance (CLT) is highly relevant under drought stress
condition. In this context, 100 tomato accessions were evaluated in brick structures under
normal conditions to study the genetic variability for root architecture and CLT. Study
indicated a wide and significant variation among the accessions for all the root traits and
CLT. Based on root dry weight, total biomass and CLT, six contrasting lines (high root
lines (HRL)-Arka Ashish (ACC 100), IIHR2617 (ACC 88), IIHR 2624 (ACC 74), IIHR
2622 (ACC 72) and low root lines (LRL) -IIHR2615 (ACC 86) and IIHR2613 (ACC 84))
were identified and further subjected to different levels of soil moisture stress viz., 100, 80
and 60 % FC by gravimetrical approach at whole plant level. Physiological, biochemical
and expression studies were quantified; HRL’s performed well compared to LRL’s.
Additionally, selected accessions were further assessed for salinity stress (whole plant
level), oxidative and high temperature stress (Seedling level). HRL showed higher
morphological, agronomical and ancillary parameters compared to LRL. Further, these
accessions were validated by grafting approach, three types of grafted plants were
generated (hetero, homo and ungrafted) to assess the drought stress response,
morphological and yield parameters were recorded and analyzed. Stress imposition
caused a significant reduction in various physiological, morphological and yield
parameters in low root lines as compared to high root line plants.