Effect of heat stress on wheat tillering and its molecular characterization
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Date
2020
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Publisher
DRPCAU, Pusa
Abstract
Tillering is one of the most important agronomic traits in cereal crops like
wheat. It determines the number of spike and panicles per plant, thus affects the
biomass and grain yield. It is very sensitive to temperature and often gets affected by
the heat stress resulting in low yield in the crop. In the current study, 40 doubled
haploid (DH) lines were sown under normal and late sown conditions to assess the
effect of temperature on tillering and grain yield. Under normal sown conditions, the
average tiller number was 154.6 tiller per meter with grain yield of 170.7g. During the
period, the average temperature between the sowing to the jointing stage was 24.6℃.
While, during the tillering (21DAS to 45DAS), the average temperature was recorded
as 20.3℃. The DH lines JR 7, JR 56, JR 75, JR 80, JR 117, JR 118, JR 142, JR 143,
JR 159, PBW343 fell in the category of high tillering under normal sown unstressed
growing condition. Under the late sown condition, the average tiller number was
136.05 tiller per meter, with the average grain yield of 96.36 g. The average
temperature between the sowing to the jointing stage of the late sown was 22.8℃.
While during the tillering (21DAS to 45DAS), the average temperature was recorded
as 21.9℃. The DH lines JR 2, JR 56, JR 104, JR 118, JR 119, JR 142, JR 143, JR
148, JR 168, KSG 1186 exhibited high tillering during the late sown (stressed)
condition. Analysis of variance indicated a significant difference among the doubled
haploid lines for the character under consideration for two different dates of sowing.
The available sequence information of “tin” and monoculm genes, related to
tillering in the plant, was used, and three gene-specific microsatellite primer pairs
were designed with the help of appropriate bioinformatics tools. The primer pairs
were used to characterize 40 DH lines under study. Reproducible amplification was
achieved. Polymorphic information content of these 3 microsatellite primers ranged
from 0.8 to 0.9, with an average value of 0.89. A total of 36 alleles were detected in
the studied lines, out of which 7 were unique, and 29 were shared alleles. The genes
specific designed microsatellite primers revealed ample genetic divergence at the
molecular level amongst the wheat genotypes. Pair-wise Similarity Coefficient ranged
from 0 to 1. Cluster analysis grouped the DH lines understudy into nine different
clusters at phenone level 10 (coefficient 0.1).