Elucidation of thermotolerance diversity in cotton (Gossypium hirsutum L.) using physio-molecular approaches

Abstract

ABSTRACT. Cotton (Gossypium hirsutum) is an important cash crop, but high temperature during its growing season is one of the major factors that limit its productivity. This problem compels plant breeders to breed for heat tolerance, which can help to overcome this challenge. It is very important to make a comprehensive screening of heat-tolerant genotypes so that only the best are chosen. Here we report the combined use of several techniques that can help breeders to screen their germplasm. Twelve cultivated cotton genotypes were evaluated for thermotolerance, using assays that included electrolyte leakage, chlorophyll accumulation and protein profiling, as well as RAPDs to assess genetic diversity. Two genotypes (B-557 and NIAB-78) showed tolerant behavior in three thermotolerance assays. RAPD analysis results showed maximum similarity in a range of 86.7-66.7% between the genotypes MNH-554 and CIM-443. We conclude that combined use should be made of relative electrolyte leakage, chlorophyll stability and differential display with SDS-PAGE to aid in screening for stress Thermotolerance diversity in Gossypium hirsutum tolerance. RAPD-based diversity analysis will further help to improve the efficiency of breeding programs.

Identification and Characterization of Contrasting Genotypes/Cultivars for Developing Heat Tolerance in Agricultural Crops: Current Status and Prospects

“…Cotton genotypes grown in a controlled environment under optimal conditions (35/21 ± 2 • C) for 30 days and then exposed to high temperature (46/30 ± 2 • C) at the reproductive stage, by gradually increasing temperature by 2 • C per day, were screened for CMT-cultivars FH-900, MNH-552, CRIS-19, and Karishma emerged as relatively heat-tolerant (thermostable) and FH-634, CIM-448, HR109-RT, and CIM-443 as heat-susceptible (Rahman et al, 2004). In a similar study at > 32 • C, cotton genotypes B557 and NIAB-78 showed minimum electrolyte leakage (<40%) and were regarded as tolerant compared to genotypes MNH-554, FH682 and FH900 which showed maximum electrolyte leakage (>50%) (Rana et al, 2011). Abro et al (2015) reported cotton varieties NIA-80, NIA-81, NIA-83, NIA-84, NIA-M-30, NIA-M31, NIA-HM-48, NIA-HM-327, NIA-H-32, NIA-HM-2-1, NIA-Bt1, NIA-Bt2, NIA-Perkh, CRIS-342, CRIS-134, and NIAB-111 and check variety Sadori as heat-tolerant using CMT as a screening parameter in both heat-stressed (44 • C) and non-stressed (32 • C) temperature regimes.…”

Some like it hot, some like it warm: Phenotyping to explore thermotolerance diversity

“…Quantification of electrolyte leakage has been used to evaluate the genotypic contributions to high temperature responses in heat tolerant cultivars of both wheat and cotton [64, 66, 67]. Although the triphenyltetrazolium chloride reduction assay has been useful in several crop studies this approach is not commonly used in molecular genetic heat stress response studies.…”

“…Seventeen were associated with both stresses while 16 were exclusively associated with heat stress, demonstrating that this approach can be used to dissect complicated stress traits [71]. Even without determining the chromosomal locations of heat stress genes in crop plants, molecular genotyping technologies such as restriction fragment length polymorphisms (RFLPs), random amplification of polymorphic DNAs (RAPDs), amplified fragment length polymorphisms (AFLPs), microsatellites, and single-nucleotide polymorphisms (SNPs) have been used to estimate the genetic contributions underlying variation in crop plant heat tolerance [67, 70, 72–74]. …”

Genetic analysis of drought tolerance with respect to fiber traits in upland cotton

“…Based on positive correlations between shoot length, root length, root and shoot dry weight, it was recommended that these should be simultaneously selected as indices of drought tolerance. Rana et al (2011) recommended the combined use of relative electrolyte leakage, chlorophyll stability, and differential sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) data obtained during stress tolerance screening. Such screening parameters are useful in programs aimed at developing drought-tolerant cotton varieties if variability is genetically controlled.…”