Marker Assisted Selection for Relative Water Content, Excised leaf Water Loss and Cell Membrane Stability in Cotton

Background: Drought stress is a major limitation in agricultural productivity. In cotton, drought tolerance is a multi-genic trait. The quantitative trait loci (QTLs), conferring drought tolerance in cotton, could be exploited for stress breeding using marker assisted selection.Methods: We have screened drought related varieties of Pakistan using DNA markers to identify reported QTLs for drought tolerance. A total of 44 of these varieties were selected. All varieties were sown in the field to record relative water content, excised leaf water loss and cell membrane stability under drought stress condition. QTLs for relative water content, excised leaf water loss and cell membrane stability were checked from all varieties by using DNA markers NAU-2954, NAU-2715, NAU-6672, NAU-8406 and NAU-6790.Results: Genotypic and phenotypic results showed that the QTL for relative water content qtlRWC-1 present on chromosome 23, linked marker NAU-2954, could be a major QTL conferring drought tolerance in cotton. Using Marker Assisted Selection the variety CRIS-134 showed all concerned QTLs for drought tolerance.Conclusion: QTL for relative water content qtlRWC-1 could be a major QTL for drought stress tolerance in cotton. The variety CRIS-134 may be used for breeding drought tolerant cultivar

Molecular Markers and Cotton Genetic Improvement: Current Status and Future Prospects

Narrow genetic base and complex allotetraploid genome of cotton (Gossypium hirsutum L.) is stimulating efforts to avail required polymorphism for marker based breeding. The availability of draft genome sequence of G. raimondii and G. arboreum and next generation sequencing (NGS) technologies facilitated the development of high-throughput marker technologies in cotton. The concepts of genetic diversity, QTL mapping, and marker assisted selection (MAS) are evolving into more efficient concepts of linkage disequilibrium, association mapping, and genomic selection, respectively. The objective of the current review is to analyze the pace of evolution in the molecular marker technologies in cotton during the last ten years into the following four areas: (i) comparative analysis of low- and high-throughput marker technologies available in cotton, (ii) genetic diversity in the available wild and improved gene pools of cotton, (iii) identification of the genomic regions within cotton genome underlying economic traits, and (iv) marker based selection methodologies. Moreover, the applications of marker technologies to enhance the breeding efficiency in cotton are also summarized. Aforementioned genomic technologies and the integration of several other omics resources are expected to enhance the cotton productivity and meet the global fiber quantity and quality demands

Marker Assisted Selection for Relative Water Content, Excised leaf Water Loss and Cell Membrane Stability in Cotton

Background: Drought stress is a major limitation in agricultural productivity. In cotton, drought tolerance is a multi-genic trait. The quantitative trait loci (QTLs), conferring drought tolerance in cotton, could be exploited for stress breeding using marker assisted selection. Methods: We have screened drought related varieties of Pakistan using DNA markers to identify reported QTLs for drought tolerance. A total of 44 of these varieties were selected. All varieties were sown in the field to record relative water content, excised leaf water loss and cell membrane stability under drought stress condition. QTLs for relative water content, excised leaf water loss and cell membrane stability were checked from all varieties by using DNA markers NAU-2954, NAU-2715, NAU-6672, NAU-8406 and NAU-6790. Results: Genotypic and phenotypic results showed that the QTL for relative water content qtlRWC-1 present on chromosome 23, linked marker NAU-2954, could be a major QTL conferring drought tolerance in cotton. Using Marker Assisted Selection the variety CRIS-134 showed all concerned QTLs for drought tolerance. Conclusion: QTL for relative water content qtlRWC-1 could be a major QTL for drought stress tolerance in cotton. The variety CRIS-134 may be used for breeding drought tolerant cultivar