Differential
response of pearl millet genotypes to
high
temperature stress at flowering
A.K.
Jukanti*, V.K. Manga, R.K. Bhatt? and R. Pathak
Division of Plant
Improvement, Propagation and Pest Management, ICAR-Central Arid Zone Research
Institute, Jodhpur-342 003, India
*Corresponding
Author E-mail: aravindjukanti@gmail.com
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Key
words
Heat stress,
Pearl millet cultivars,
Stress indices
Publication Data
Paper received : 10.08.2016
Revised received : 18.11.2016
Re-revised received :
06.12.2016
Accepted : 20.12.2016
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Abstract
Aim: Pearl millet is
emerging as an important irrigated summer crop in India and Africa. Flowering
during summer coincides with high temperature resulting in reduced grain
yield. Due to limited cultivar options for summer, different types of pearl
millet genotypes were evaluated to identify sources of high temperature
tolerance.
Methodology:
Fourteen
pearl millet cultivars (4 each of population and hybrids; 3 each of inbred
restorers and MS lines) were evaluated under two sowing dates in such a way
that the flowering was not/minimally affected by high temperature stress
(non-stress - NST) and the flowering largely coincided with high temperature
(≥ 42oC), impacting the seed set and grain yield (stress - ST). The
data on different parameters including grain yield was recorded and different
stress indices were estimated.
Results:
The
total number of days each genotype flowered was reduced by ~2 ? 3 days under
high temperature stress, probably an inherent avoidance mechanism. Per cent
decrease in seed set and grain yield under stress was 2.4 ? 29.9 and 12.2 ?
40.9, respectively. High temperature stress (≥42oC) during
flowering stage resulted in reduced seed set, tip sterility and reduced
panicle exertion. Increased vegetative growth (plant height) coupled with
reduction in grain yield were recorded for all the genotypes under heat
stress. Under temperature stress, hybrids outperformed the others in terms of
seed set and grain yield. Based on heat tolerance/susceptibility indices,
seed set and grain yield CZH 233, CZP 9603, CZI 2011/5 and CZMS 21A were the
best performing genotypes. ?????
Interpretation:
High
temperature affects the assimilate production and reproductive growth,
thereby significantly reduced the grain yield. The results demonstrated that
flowering period is an important heat sensitive stage. Genetic variability
exists for flowering stage high temperature tolerance in pearl millet which
can be utilized in developing improved cultivars for summer cultivation.
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enforced or derived, rest completely with the author(s).
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