Cotton is one of the most important crops among natural fibres. Fibre quality determines the spinning ability, which is negatively correlated with yield and yield-contributing traits. Limited efforts have been made to improve fibre quality and yield in diploid cotton. Therefore, screening a large panel of germplasm lines can help identify genotypes with better fibre quality and yield. We evaluated 712 desi cotton genotypes for fibre quality traits. The genotypes showed a significant difference for all the traits, suggesting considerable variability for fibre quality improvement. Fibre length and strength showed high phenotypic and genotypic coefficients of variation. Heritability was high for fibre strength, length, and elongation. Fibre length and strength were positively correlated; however, micronaire was negatively correlated with these two traits. Superior accessions were identified for fibre length (11), strength (20), uniformity (7), and elongation (25) among genotypes. Most of the desi lines (71%) had medium micronaire values. Twenty accessions identified were ideal for spinning, showing the fibre strength-to-length ratio of one. Cluster analysis based on Euclidean distance grouped all 712 accessions into four major clusters. Principal component analysis biplot revealed that accessions AC3418, 360-SP1, AC3522B, Kanpur A, Gao16CB-9, and AC3370 were genetically diverse. The superior accessions for fibre quality identified in this study are potential lines for the diploid cotton improvement programme.

Diploid (2n = 2x = 20) and triploid (2n = 3x = 30) Fasciola hepatica have been reported in the UK, and in Asia diploid, triploid and mixoploid (2x/3x) Fasciola spp. exist but there is little information to indicate how common triploidy is, particularly in UK fluke. Here the ploidy of 565 adult F. hepatica from 66 naturally infected British sheep and 150 adult F. hepatica from 35 naturally infected British cattle was determined. All 715 of these parasites were diploid, based on observation of 10 bivalent chromosomes and sperm (n = 335) or, since triploids are aspermic, sperm alone (n = 380). This constitutes the first extensive analysis of the ploidy of F. hepatica field isolates from Great Britain and shows that most F. hepatica isolated from cattle and sheep are diploid and have the capacity to sexually reproduce. These data suggest that triploidy, and by extension parthenogenesis, is rare or non-existent in wild British F. hepatica populations. Given that F. hepatica is the only species of Fasciola present in Britain our results indicate that the parasite is predominantly diploid in areas where F. hepatica exists in isolation and suggests that triploidy may only originate in natural populations where co-infection of F. hepatica and its sister species Fasciola gigantica commonly occurs.

To preliminarily evaluate the genetic diversity of the Iranian diploid Triticum L. gene pool, in this study, a total of 176 individuals belonging to T. monococcum L. ssp. aegilopoides (Link) Thell. and T. urartu Thum. ex Gandil. were pre-screened using single-strand conformation polymorphism (SSCP) analysis of the Acc-1 and Pgk-1 loci. A selected set of 76 DNA samples corresponding to the observed SSCP variants were sequenced for both loci and evaluated for nucleotide diversity associated with the taxonomic groups and geographical regions. We found three haplotypes, including one that was new for Iran, at each locus. Population structure and analysis of molecular variation results proved that the collection evaluated could be genetically divided into two distinct groups, which to a great extent was in accordance with the taxonomic classification. A genetic leakage from T. monococcum ssp. aegilopoides into T. urartu was observed during structure analysis, which was inferred on the basis of occasional outcrossing, despite their inbreeding nature. The results revealed that there was no variation within the populations belonging to T. urartu, while a meaningful variation was found between the geographical regions for T. monococcum ssp. aegilopoides. The median-joining networks revealed a conflict between morphology and haplotype variation, which was interpreted on the basis of introgressive hybridization, recombination signature and rapid speciation. In conclusion, we suggest that SSCP analysis is a useful tool in regions where thorough sequencing of an enormous number of DNA samples is time consuming and not affordable.

The objective of this study was to determine developmental pattern, total cell number, apoptosis and apoptosis-related gene expression in haploid and diploid embryos following parthenogenetic activation. In vitro-matured porcine oocytes were activated by electrical pulses and cultured in the absence or presence of cytochalasin B for 3 h. Zygotes with two polar bodies (haploid) and one polar body (diploid) were carefully selected and were further cultured in NCSU 23 medium containing 0.4% bovine serum albumin (BSA) for 7 days. The percentage of development to blastocyst stage was higher (p<0.01) in the diploid than in the haploid parthenotes. In haploid blastocysts, average total cell number was significantly reduced (p<0.05) and apoptosis was increased at day 7. The relative abundance of Bcl-xL and Bak mRNA in the diploid blastocysts was similar to that of in vivo-fertilized embryos. However, Bcl-xL was significantly decreased, and Bak mRNA was significantly increased (p<0.05) in haploid parthenotes compared with the diploid parthenotes. These results suggest that the haploid state affects apoptosis-related gene expression which results in increased apoptosis and decreased developmental competence of haploid parthenotes.

The growth response of diploid (2n) and thermally-induced triploid (3n) coho salmon to injected recombinant porcine somatotropin was examined over a 10 week period. All treatments were under-taken using replicate groups of 25 animals per group. Control 2n and 3n replicate groups grew at identical rates throughout the period of study, although 3n fish exhibited lower condition factors. Recombinant poreine somatotropin treated 2n and 3n fish responded positively to therapy and, by week 4 of the trial, expressed significantly greater increases in both weight and length (p < 0.01) when compared to controls. At the end of the study period, soinatotropin treated animals had gained approximately twice the amount of weight of controls. Food conversion efficiencies were greater in treated salmon, regardless of ploidy state. This relationship also extended to weight and length specific growth rates. The economic benefits of commercial application of recombinant porcine somatotropin therapy to triploid Pacific salmon culture are discussed.

This work studies the long-term effects of mutation and selection pressures on a diploid population embracing many genetic types. A number of results previously established for the simpler asexual case (see [4]) are extended to the cases of random mating and complete inbreeding (Theorem 1), and then, under particular conditions, to certain circumstances of mixed random mating and inbreeding (Theorem 3 and Corollary 1). Several implications for sex and diploidity are drawn from Theorem 2 and its corollaries. Further biological interpretations of these findings, especially of Theorem 2, are given in [3].