GENETIC VARIABILITY FOR SELECTIVE TOLERANCE TO POST EMERGENCE WEEDICIDE IN CHICKPEA (Cicer arietinum L.)
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Date
2016
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Acharya N.G. Ranga Agricultural University
Abstract
The present investigation entitled ‘Genetic variability for selective
tolerance to post emergence weedicide in chickpea (Cicer arietinum L.)’ was
carried out during rabi, 2015-16 at Regional Agricultural Research Station,
Nandyal, Andhra Pradesh, India. Thirty chickpea genotypes were evaluated in
Randomized Block design with three replications each in ‘spay’ and ‘control’. Post
emergence herbicide imazethapyr was sprayed at 30 days after sowing and
herbicide tolerance scores (HTS) at 10, 20 and 30 days after spray were recorded
using 1-5 scale (1 = highly tolerant and 5 = highly sensitive). The experiment in
which herbicide was applied is designated as ‘spray’ and a control block without
herbicide spray (designated as ‘control’) was also grown to evaluate the influence
of herbicide on yield and yield attributes of chickpea.
The analysis of variance revealed significant differences among 30
genotypes for days to 50% flowering, days to maturity, plant height, number of
branches per plant, number of pods per plant, specific leaf area, shoot biomass,
harvest index, 100 seed weight and seed yield in ‘control’ and days to 50%
flowering, days to maturity, plant height, number of pods per plant, shoot biomass,
harvest index, 100 seed weight and seed yield in ‘spray ’. The differences among
the genotypes for number of branches and specific leaf area in ‘spray’ and SPAD
Chlorophyll Meter Reading (SCMR) in both ‘control’ and ‘spray’ were not
significant.
Assessment of plant appearance and leaf symptoms after herbicide
application revealed large genetic variation for tolerance to imazethapyr in 30
chickpea genotypes. Herbicide tolerance scores (HTS) of genotypes ranged from
2.0 (ICCV 10,ICCV 08109,ICCIL 04021, ICCV 08102, ICCIL 04016, ICCV
97105, ICCV 11101, ST-3-D-2, ICCV 95008, ICCV 97007, ICCV 95013, ICCV
93122, ICCV 93054, ICCV 96005, ICC 1205 and N BeG 119) to 3.7 (N BeG 47 )
at 10 days after spray. At 30 days after spray, except JG 11(2.3) all the genotypes
recovered fully and recorded HTS of 2.0. The overall decrease in seed yield due to
imazethapyr was 18.5 % and it ranged from 1.63% (ICCIL 01031) to 45% (ICCIL
04004). A few promising chickpea lines viz., ICCIL 01034 , ICCV 09106, ICCIL
01026, ICCIL 01031, ST-3-D-2, N BeG 49 , N BeG 3, N BeG 47 and JG 11with
tolerant to moderately tolerant reaction to imazethapyr, and with high yield in
‘spray’ as well as ‘control’ were identified in the study and can be utilized further
in breeding programmes.
Study of genetic variability revealed that in both ‘control’ and ‘spray’,
higher PCV and GCV values were recorded for seed yield. High PCV and GCV
values were also recorded for specific leaf area in ‘control’ and 100 seed weight in
‘spray’, respectively. Shoot biomass, 100 seed weight, harvest index and seed
yield recorded high values of heritability and genetic advance in both ‘control’ and
‘spray’. Days to 50% flowering and SLA in ‘control’ also exhibited higher values
of heritability and genetic advance as per cent of mean. These characters with high
values of heritability and genetic advance under selection can be improved more
rapidly with less intensive evaluation than those with low heritability.
Genetic divergence studies clearly distinguished thirty genotypes into five
clusters. Promising genotypes along with high per se performance were N BeG 49,
ICCIL 01031, N BeG 510 and N BeG 119 from cluster I; N BeG 47 from cluster
II; ICCV 09106 from cluster III and ICCV 97007 from cluster V , which can be
utilized in crossing programme to recover an array of transgressive segregants for
various traits. Apart from these, elite genotypes with high yield and herbicide
tolerance from clusters I (ICCIL 01034 , ICCIL 01026 and JG 11) and II ( ST-3-D-
2 and N BeG 3) can also be exploited in breeding programmes meant for
improving tolerance to post emergence herbicide imazethapyr in chickpea.
Correlation and path analysis studies revealed that number of pods per
plant, shoot biomass, harvest index and 100 seed weight exhibited positive and
highly significant association with seed yield and also among themselves. On the
other hand, days to 50% flowering and days to maturity were negatively and
highly significantly correlated with seed yield. These traits followed the same
trend in both ‘control’ and ‘spray’. Whereas, some deviation was observed in traits
viz., plant height and number of branches per plant in ‘control’ and ‘spray’. Thus
the correlated traits must be carefully studied while breeding for high yield along
with tolerance to post emergence herbicide in chickpea. High seed yield is
determined based on shoot biomass and harvest index in chickpea in both ‘control’
and ‘spray’ and these traits emerged as major contributors of seed yield as
evidenced from their high direct effects as well as indirect via contributions of
other correlated traits (number of pods, number of branches in ‘control’ and
number of pods, 100 seed weight and plant height in ‘spray’).
Description
D5382
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