RA 00015.pdf - OAR@ICRISAT

weight and leaf area of the seedlings at 16 days
after sowing (r = 0.82**), but by 30 days after
sowing the relationship was less close
(r = 0.57**) (Fig 40). The larger-seeded cultivars
also had larger leaves (r = 0.86** for the
relationship between maximum area per leaf on
80-day-old plants and 100-seed weight). There
was no significant relationship between 100-seed
weight and total dry weight at harvest (r = 0.07)
or yield (r = 0.13).
300
250
200
150
100
50
0
600
500
400
300
200
100
0
A. 16 days after sowing
B. 30 days after sowing
0 4 8 12 16 20 24 28 32
Seed weight ( g / 100 seeds)
Figure 40. Relationship between 100-seed weight
and total dry weight of seedlings of 23
chickpea cultivars.
Susceptibility to iron chlorosis. A number of
cultivars grown at ICRISAT Center showed a
marked yellowing of the younger leaves during
the vegetative phase. The plants recovered spontaneously
later in the growing season. The yellowing
symptoms could be relieved by sprays of
ferrous sulphate, indicating that the symptoms
were those of iron chlorosis. In a trial with two
iron-chlorosis-susceptible cultivars we found
that the sprayed plants gave 35 percent more
yield than the controls, showing a distinct yieldreducing
effect of this undesirable cultivaral
characteristic.
Response to moisture stress. We made a preliminary
attempt to identify drought-tolerant
cultivars of chickpea by growing 71 diverse
cultivars on soil of limited moisture-holding
capacity (an Alfisol). Three sets of replicated
plots were irrigated during the growing season
and three were not. Plants in the irrigated plots
matured later and, on average, produced about
three times as much dry matter and yield as did
the nonirrigated plants, indicating that the latter
were subjected to quite severe moisture stress.
Duration of the cultivars (measured by the
number of days to flowering) was significantly
negatively related to the yield under nonirrigated
conditions (r = - 0 . 3 9 * * ) , but was not significantly
related to the yield under irrigation
(r = 0.04). The ratio of the yield without irrigation
to the yield with irrigation (which can be
regarded as an index of drought tolerance) was
significantly negatively related to the number of
days to flowering (r = - 0 . 3 3 * * ) . In other
words, the earlier cultivars tended to be more
drought-tolerant and to yield better under nonirrigated
conditions than did the later cultivars,
but this tendency explained only a small part of
the cultivaral differences.
Although the correlations between yield per
plant with and without irrigation (r = 0.60**)
and between yield per plant without irrigation
and the "drought-tolerance index" (r = 0.48**)
were significant and positive, they are not strong
enough to effectively identify-on the basis of
yield under conditions of adequate moisture -
cultivars which would yield well under drought
conditions. Nor can plants which are most
"drought tolerant" (as judged by ratio of yield
without to yield with irrigation) be reliably
identified simply by the yield produced under
moisture stress.
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