Identification of novel sources of variation for the improvement of cold germination ability and early seedling vigor in upland cotton (Gossypium hirsutum L.)

Date

2019-08

Journal Title

Journal ISSN

Volume Title

Publisher

Abstract

Cotton production is limited by the adverse effects of low temperature stress especially at the germination and early seedling stages. Due to its tropical and sub-tropical origins, cotton is extremely sensitive to low temperatures from seed germination up to maturity. The germination process is hindered when cotton seeds are exposed below the minimum cardinal temperature of 15°C. Subsequently at the early seedling stage, cotton genotypes that are susceptible to cold exhibit poor vigor. Although several mitigating strategies that involves both agricultural practices and the application of plant exogenous regulators are available, the most economical long-term solution would be to develop cultivars and varieties with tolerance to low temperatures at the germination and early seedling stage. The main goal of this study is to identify genetic variation in the available germplasm collections which can be utilized in future breeding programs aiming to improve cold germination ability and early seedling vigor in cotton at the early seedling stage. Through genotypic and phenotypic analysis, a wide variation in response to cold stress during germination is established within the Gossypium Diversity Reference Set (GDRS) and fatty acid (FA) mutants. The screening for seedling vigor was carried out using a set of morphological, physiological, and biochemical assays. A total of 18 genotypes from both test germplasm were identified exhibiting varying responses to cold stress during the early seedling stage. In addition, morphological markers such as plant height and biomass were found to be good markers in identifying seedling vigor under cold stress in cotton. Comparative transcriptome profile analysis was conducted to confirm the differences in response to cold stress at the early seedling stage at the genic level. Through further analysis and gene validation studies, the initial results of this study can be used to identify set of genes or gene networks responsible for vigor under cold stress at the early seedling stage in cotton.

Description

Keywords

Cotton, Cold stress, Genetic variation, Seedling vigor, Transcriptome

Citation