GENETIC DIVERGENCE AND DROUGHT TOLERANCE STUDIES IN SUNFLOWER (Helianthus annuus L.) GENOTYPES
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Date
2004
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ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY RAJENDRANAGAR, HYDERABAD
Abstract
In the present investigation, 100 sunflower (Helianthus annuus L.) GMU
lines were screened for their temperature tolerance by using Temperature
Induction Response (TIR) technique in laboratory conditions at DOR, Hyderabad.
Forty three genotypes along with two checks, KBSH-1 and Morden were studied
for genetic divergence. Out of 43 lines, 11 genotypes were identified as more
thermotolerant and studied along with the check variety ‘Morden’ for their
moisture stress tolerance at field level. These studies were conducted at College
Farm, College of Agriculture, Hyderabad during Summer, 2004.
From the experiment on thermotolerance screening eleven lines viz., GMU-
109, GMU-129, GMU-133, GMU-134, GMU-138, GMU-141, GMU-149, GMU-
157, GMU-175, GMU-185 and GMU-196 were identified as most thermotolerant
as they exhibited above 80 per cent seeding survival during recovery period
following the induction and lethal temperature treatmetns.
For genetic divergence studies the analysis of variance revealed significant
differences among the genotypes for all the 15 characters studied. Based on
Mahalanobis D2 analysis the 45 genotypes were grouped into 9 clusters. The
pattern of distribution of genotypes into various clusters revealed that there was
no relationship between geographical distribution and genetic diversity. Greater
genetic divergence found between cluster I and IX, suggested exploitation of these
two clusters by intermating the genotypes in a definite breeding designs to explore
the fullest range of heterosis and to realize good recombinant lines. The genotypes
GMU-104, 118 and 107 (cluster I), GMU-122 (cluster III), Morden (cluster VI)
and GMU-109, 114, 113 and 132 (cluster IX) could be considered for
recombination breeding in order to get desirable segregants with higher yield
potential.
The drought tolerance studies conducted on 12 genotypes for eleven
characters revealed that there were no significant differences among the stress
treatments for the traits, plant height, total dry matter per plant, 100-seed weight
and harvest index, while the characters head diameter, head weight, number of
unfilled seeds per head, number of filled seeds per head, seed filling per cent, seed
yield per plant and leaf area index differed significantly among the stress
treatments. All the characters studied were affected during stress imposed at
flowering except for the trait 100-seed weight which was effected more during
stress at seed filling.
The genotypes GMU-157, GMU-149, GMU-129 and GMU-185 were
found to be more tolerant to moisture stress, based on their performance for
various characters studied.
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Keywords
GENETIC, DIVERGENCE, DROUGHT, TOLERANCE, STUDIES, SUNFLOWER, (Helianthus annuus L.), GENOTYPES,