Breeding Potential of Introgression Lines Developed from Interspecific Crossing between Upland Cotton (<i>Gossypium hirsutum</i>) and <i>Gossypium barbadense</i>: Heterosis, Combining Ability and Genetic Effects

<div><p>Upland cotton (<i>Gossypium hirstum</i> L.), which produces more than 95% of the world natural cotton fibers, has a narrow genetic base which hinders progress in cotton breeding. Introducing germplasm from exotic sources especially from another cultivated tetraploid <i>G</i>. <i>barbadense</i> L. can broaden the genetic base of Upland cotton. However, the breeding potential of introgression lines (ILs) in Upland cotton with <i>G</i>. <i>barbadense</i> germplasm integration has not been well addressed. This study involved six ILs developed from an interspecific crossing and backcrossing between Upland cotton and <i>G</i>. <i>barbadense</i> and represented one of the first studies to investigate breeding potentials of a set of ILs using a full diallel analysis. High mid-parent heterosis was detected in several hybrids between ILs and a commercial cultivar, which also out-yielded the high-yielding cultivar parent in F₁, F₂ and F₃ generations. A further analysis indicated that general ability (GCA) variance was predominant for all the traits, while specific combining ability (SCA) variance was either non-existent or much lower than GCA. The estimated GCA effects and predicted additive effects for parents in each trait were positively correlated (at <i>P</i><0.01). Furthermore, GCA and additive effects for each trait were also positively correlated among generations (at <i>P</i><0.05), suggesting that F₂ and F₃ generations can be used as a proxy to F₁ in analyzing combining abilities and estimating genetic parameters. In addition, differences between reciprocal crosses in F₁ and F₂ were not significant for yield, yield components and fiber quality traits. But maternal effects appeared to be present for seed oil and protein contents in F₃. This study identified introgression lines as good general combiners for yield and fiber quality improvement and hybrids with high heterotic vigor in yield, and therefore provided useful information for further utilization of introgression lines in cotton breeding.</p></div

Upland Cotton Gene <i>GhFPF1</i> Confers Promotion of Flowering Time and Shade-Avoidance Responses in <i>Arabidopsis thaliana</i>

<div><p>Extensive studies on floral transition in model species have revealed a network of regulatory interactions between proteins that transduce and integrate developmental and environmental signals to promote or inhibit the transition to flowering. Previous studies indicated <i>FLOWERING PROMOTING FACTOR 1</i> (<i>FPF1</i>) gene was involved in the promotion of flowering, but the molecular mechanism was still unclear. Here, <i>FPF1</i> homologous sequences were screened from diploid <i>Gossypium raimondii</i> L. (D-genome, n = 13) and <i>Gossypium arboreum</i> L. genome (A-genome, n = 13) databases. Orthologous genes from the two species were compared, suggesting that distinctions at nucleic acid and amino acid levels were not equivalent because of codon degeneracy. Six <i>FPF1</i> homologous genes were identified from the cultivated allotetraploid <i>Gossypium hirsutum</i> L. (AD-genome, n = 26). Analysis of relative transcripts of the six genes in different tissues revealed that this gene family displayed strong tissue-specific expression. <i>GhFPF1</i>, encoding a 12.0-kDa protein (Accession No: KC832319) exerted more transcripts in floral apices of short-season cotton, hinting that it could be involved in floral regulation. Significantly activated <i>APETALA 1</i> and suppressed <i>FLOWERING LOCUS C</i> expression were induced by over-expression of <i>GhFPF1</i> in the <i>Arabidopsis</i> Columbia-0 ecotype. In addition, transgenic <i>Arabidopsis</i> displayed a constitutive shade-avoiding phenotype that is characterized by long hypocotyls and petioles, reduced chlorophyll content, and early flowering. We propose that <i>GhFPF1</i> may be involved in flowering time control and shade-avoidance responses.</p></div

Additional file 1: of Genetic analysis of Verticillium wilt resistance in a backcross inbred line population and a meta-analysis of quantitative trait loci for disease resistance in cotton

Mapping of quantitative trait loci for Verticillium wilt resistance in a backcross inbred line population of (SG 747 × Giza 75) × SG 747 BC 2 F 4

El Diario de Pontevedra : periódico liberal: Ano XL Número 11660 - 1923 outubro 24

Chromosome distribution of 239 DEGs with SNP/InDels between “Long” and “Short” in the Gossypium hirsutum genome from A01 to A13, and from D01 to D13. Genes with InDels are indicated in blue. (PDF 1348 kb

Expression patterns of <i>GhFPF1</i>, <i>GhFLP-1</i>, <i>GhFLP-2</i>, <i>GhFLP-3</i>, <i>GhFLP-4</i>, and <i>GhFLP-5</i> in <i>G. hirsutum</i> L.

<p>Relative expression of <i>GhFPF1</i> and its homologs were measured in different tissues of upland cotton CCRI 36 (a short-season cotton variety) and TM-1 (a genetic standard line) using qRT-PCR. Roots, stems, leaves, flowers and fibers stand for mixed samples from CCRI 36 and TM-1. Floral apices from CCRI 36 and TM-1 were harvested and named as floral apices T and C respectively. Error bars represent standard deviation (SD).</p

Additional file 1: Table S1. of Identification of candidate genes for fiber length quantitative trait loci through RNA-Seq and linkage and physical mapping in cotton

Average fiber quality of the two BILs tested in different environments based on Yu et al. [37]. (DOC 15 kb

Gene structure of <i>GhFPF1</i>, and its response to plant hormones.

<p>A. The gene structure of <i>GhFPF1</i>. JA and SA represent response elements of JA and SA; TSS, transcriptional start site. B. <i>GhFPF1</i> and <i>GhNPR1</i> expression profiles in the first forty-eight hours after treatment with SA and JA. <i>GhNPR1</i> (DQ409173), a known JA- and SA-inducible gene, was used as a positive control here. Error bars represent SD.</p

Statistics of hypocotyl and petiole lengths of wild and transgenic plants grown under long-day conditions with fluorescent lamps.

<p>Hypocotyl lengths of wild and transgenic lines were quantified from thirty ten-day-old plants. Petiole lengths of true leaves of the basal rosette were measured and the data were gathered from thirty wild type and transgenic 24-day-old plants, respectively. Mean values (±SD) were shown and statistical analysis was evaluated by the same way as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0091869#pone-0091869-t002" target="_blank">table 2</a>.</p

Flowering time under long-day conditions, as measured by days to flowering and number of basal rosette and cauline leaves.

<p>Asterisks indicate significant variation differences between the wild-type and each <i>35S::GhFPF1</i> transgenic population line as determined by one-way ANOVA analysis. Means with SD from twenty plants of every line were shown.</p

Over-expression of <i>GhFPF1</i> led to shade-avoidance responses in transgenic plants.

<p>A. Phenotype of hypocotyl of ten-day-old wild type (left) and transgenic plants (right) grown under long-day conditions. B. The seventh rosette leaves of wild type (left) and transgenic (right) 24-day-old plants grown under the same conditions as (A). C. Shade-avoidance responses in 24-day-old transgenic plants (right) which grew fast with upward leaves. All <i>Arabidopsis</i> plants were grown under long-day conditions with high red/far red (R/FR ratio: 4.5) light provided by fluorescent lamps. D. Chlorophyll content of leaves in transgenic plants was lower than that in wild-type and the difference was very significant (P<0.01) assessed by T-test. E. The transcript levels of <i>AtPHYB</i> (AT2G18790) in wild-type and <i>GhFPF1</i> over-expression transgenic plants. The <i>AtUBQ5</i> gene was used as calibrator.</p