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A pinboard by
OLUOCH GEORGE

PhD STUDENT, MASENO UNIVERSITY

PINBOARD SUMMARY

Soil salinity negatively affects growth and development as well as yield and fiber quality of cotton. The identification of quantitative trait loci (QTLs) for traits related to salt tolerance could facilitate the development of cotton cultivars with salt tolerance. The objective of this study was to map QTLs for salt tolerance in an F2:3 population derived from an interspecific cross between an upland cotton, CRI-12 (G09091801-2), of upland cotton (Gossypium hirsutum) and an accession, AD3-00 (P0601211), of wild cotton Gossypium tomentosum. 1295 simple sequence repeat markers, which amplified 1342 loci, distributed on 26 chromosomes and covered 3328.24 cM with an average inter-marker distance of 3.0 cM, were utilized for molecular genotyping. Salt tolerance was evaluated in a hydroponic at a young seedling stage for 2 weeks at 150 mM NaCl concentration in three environments. Mapping of QTLs related to salt tolerance was carried out on 7 traits by composite interval mapping using Windows QTL Cartographer 2.5. Eleven consistent QTLs were detected on 8 chromosomes (9, 11, 15, 16, 21, 23, 24 and 26) in at least two environments. qRL-Chr16-1 for RL was a major QTL explaining the Phenotypic variance of 11.97 and 18.44 % in two environments. Of the 11 QTLs, 10 were located on the D subgenome, indicating that genes responsible for salt tolerance in the allotetraploid cotton AD genome were mainly derived from the D subgenome. The information derived from these studies may be useful in facilitating breeding of salt tolerant cotton lines.

4 ITEMS PINNED

Genetic mapping of quantitative trait loci conditioning salt tolerance in wild soybean (Glycine soja) PI 483463

Abstract: Salt tolerance in soybean [Glycine max (L.) Merr.] is controlled by major quantitative trait loci (QTL) or single gene(s). Among soybean germplasm, wild soybean plant introduction PI 483463 was reported to have a single dominant gene for salt tolerance. The objective of this study was to genetically map the QTL in a recombinant inbred line (RIL) population derived from a cross between PI 483463 and Hutcheson. Simple sequence repeat (SSR) markers and universal soybean single nucleotide polymorphism (SNP) panel (the USLP 1.0) were utilized for molecular genotyping. The RILs were phenotyped in two independent tests in a greenhouse using a 1–5 scale visual rating method. The results showed that the salt tolerant QTL in PI 483463 was mapped to chromosome 3 in a genomic region between the Satt255 and BARC-038333-10036 markers. The favorable allele inherited from PI 483463 conferred tolerance to salinity and had an additive effect on reducing leaf scorch. A subset of 66 iso-lines was developed from the F3 families of the same cross and was used for genetic confirmation of the QTL. The integration of recombination events and the salt reaction data indicate that the QTL is located in the region of approximately a 658 kb segment between SSR03_1335 at nucleotide 40,505,992 and SSR03_1359 at nucleotide 41,164,735 on chromosome 3. This narrow region can facilitate further genomic research for salt tolerance in soybean including cloning salt tolerance genes.

Pub.: 16 Jun '13, Pinned: 23 Sep '17

QTL mapping for salt tolerance at seedling stage in the interspecific cross of Gossypium tomentosum with Gossypium hirsutum

Abstract: Soil salinity negatively affects growth and development as well as yield and fiber quality of cotton. The identification of quantitative trait loci (QTLs) for traits related to salt tolerance could facilitate the development of cotton cultivars with salt tolerance. The objective of this study was to map QTLs for salt tolerance in an F2:3 population derived from an interspecific cross between an upland cotton, CRI-12 (G09091801-2), of upland cotton (Gossypium hirsutum) and an accession, AD3-00 (P0601211), of wild cotton Gossypium tomentosum. 1295 simple sequence repeat markers, which amplified 1342 loci, distributed on 26 chromosomes and covered 3328.24 cM with an average inter-marker distance of 3.0 cM, were utilized for molecular genotyping. Salt tolerance was evaluated in a hydroponic at a young seedling stage for 2 weeks at 150 mM NaCl concentration in three environments. Mapping of QTLs related to salt tolerance was carried out on 7 traits by composite interval mapping using Windows QTL Cartographer 2.5. Eleven consistent QTLs were detected on 8 chromosomes (9, 11, 15, 16, 21, 23, 24 and 26) in at least two environments. qRL-Chr16-1 for RL was a major QTL explaining the Phenotypic variance of 11.97 and 18.44 % in two environments. Of the 11 QTLs, 10 were located on the D subgenome, indicating that genes responsible for salt tolerance in the allotetraploid cotton AD genome were mainly derived from the D subgenome. The information derived from these studies may be useful in facilitating breeding of salt tolerant cotton lines.

Pub.: 07 Mar '16, Pinned: 23 Sep '17

SSR-based association mapping of salt tolerance in cotton (Gossypium hirsutum L.).

Abstract: The identification of simple sequence repeat (SSR) markers associated with salt tolerance in cotton contributes to molecular assisted selection (MAS), which can improve the efficiency of traditional breeding. In this study, 134 samples of upland cotton cultivars were selected. The seedling emergence rates were tested under 0.3% NaCl stress. A total of 74 SSR markers were used to scan the genomes of these samples. To identify SSR markers associated with salt tolerance, an association analysis was performed between salt tolerance and SSR markers using TASSEL 2.1, based on the analysis of genetic structure using Structure 2.3.4. The results showed that the seedling emergence rates of 134 cultivars were significantly different, and 27 salt-sensitive and 10 salt-tolerant cultivars were identified. A total of 148 loci were found in 74 SSR markers involving 246 allelic variations, which ranged from 2 to 7 with an average of 3.32 per SSR marker. The gene diversity ranged from 0.0295 to 0.4959, with the average being 0.2897. The polymorphic information content ranged from0.0290 to 0.3729, with the average being 0.2381. This natural population was classified into two subgroups by Structure 2.3.4, containing 89 and 45 samples, respectively. Finally, eight SSR sites associated with salt tolerance ware found through an association analysis, with the rate of explanation ranging from 2.91 to 7.82% and an average of 4.32%. These results provide reference data for the use MAS for salt tolerance in cotton.

Pub.: 21 Jun '16, Pinned: 23 Sep '17