Under well watered condition, differences among Jerusalem
artichoke genotypes were significant for root dry weight and root
diameter (Table 3). Jerusalem artichoke genotypes could be classified
into the group with high root dry weight and the group with
low root dry weight. JA 89 and HEL 65 exhibited the highest root dry weight and root diameter. In contrast, JA 5, JA 60 and JA 125
showed the lowest root dry weight and root diameter.
Under mild water stress, JA 125 performed well as it had high
root dry weight and DTI for root dry weight, whereas JA 5 and JA 60
had low root dry weight and high DTI of root dry weight. In
contrast, JA 89 and HEL 65 were categorized into the group with
high root dry weight and low DTI for root dry weight.
JA 125, JA 89 and HEL 65 had high root diameter and high DTI for
root diameter, whereas JA 60 and JA 5 had low root diameter and
high DTI of root diameter. However, the differences among five
Jerusalem artichoke genotypes for root dry weight and root diameter
under severe water stress were not significant.
Jerusalem artichoke genotypes responded differently for root:
shoot ratio, root length, root surface and root volume under well
watered conditions in both years (Table 4). JA 89 and HEL 65 had
high root: shoot ratio, root length, root surface area and root volume
under well watered conditions in both years. JA 125 and JA 5
had low root: shoot ratio, root length, root surface and root volume
under well watered conditions in both years. JA 60 had high, root
length, root surface and root volume under well watered conditions
in 2013 only.
Severe water stress increased root: shoot ratio in JA 60, JA 125 JA
5 and HEL 65 in both years, whereas JA 89 did not respond to
drought for root: shoot ratio. JA 60 performed well for root: shoot
ratio under mild and severe water stress conditions in both years. JA
125 also performed well under mild and severe water stresses as it
had highest DTI of root: shoot ratio in both years, whereas JA 89
performed poorly as it had low DTI for root: shoot ratio in both
years.
JA 125 performed well for root length under mild and severe
water stress in both years as it had high root length and DTI of root
length in both years. JA 125 and JA 5 had high DTI of root length
under mild and severe water stress in both years but JA 89 and HEL
65 had rather low DTI of root length under mild and severe water
stress in both years. JA 125 had high root surface and DTI for root
surface under mild and severe water stresses in both years, whereas
JA 89 and HEL 65 had high root surface but they had low DTI of root
surface under mild and severe water stress in both years. JA 125 and
JA 5 showed consistently high DTI for root volume under mild and
severe water stress. JA 125 had also high root volume under mild
and severe water stress in both years.
JA 125 had high root dry weight, root diameter, root: shoot ratio,
root length, root surface, root volume across years, and values of
DTI for these traits under mild and severe water stress were also
high. JA 60 was identified as the genotype with high DTI of root dry
weight, root diameter and root: shoot ratio under mild and severe
water stress. JA 5 was identified as the genotype with high DTI of
root dry weight, root diameter, root length, root surface and root
volume under mild and severe water stress. JA 89 and HEL 65
performed well for root dry weigh, root diameter, root length and
low DTI of all root characteristics. JA 125, JA 60 and JA 5 consistently
performed well under drought stress by maintaining the ability to
absorb water by having high DTI of some root traits.