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Autopolyploidy and allopolyploidy may represent an evolutionary advantage and are more common in plants than assumed. However, less attention has been paid to autopolyploidy than to allopolyploidy, and its evolutionary consequences are largely unclear, especially for plants with high ploidy levels. In this study, we developed oligonucleotide (oligo)-based chromosome painting probes to identify individual chromosomes in S. spontaneum. Using fluorescence in situ hybridization (FISH), we investigated chromosome behavior during pachytene, metaphase, anaphase, and telophase of meiosis I (MI) in autotetraploid, autooctoploid, and autodecaploid S. spontaneum clones. All autopolyploid clones showed stable diploidized chromosome behavior; so that homologous chromosomes formed almost exclusively bivalents during MI. Two copies of homologous chromosome 8 with similar sizes in the autotetraploid clone showed preferential pairing with each other with respect to the other copies. However, sequence variation analysis showed no apparent differences among homologs of chromosome 8 and all other chromosomes. We suggest that either the stable diploidized pairing or the preferential pairing between homologous copies of chromosome 8 in the studied autopolyploid sugarcane are accounted for by unknown mechanisms other than DNA sequence similarity. Our results reveal evolutionary consequences of stable meiotic behavior in autopolyploid plants. [ABSTRACT FROM AUTHOR]

The Saccharum genus comprises species with large and variable chromosome numbers, leading to challenges in genomic studies and breeding improvement. Cytogenetics, including classical and molecular approaches, has played a central role in deciphering the genome structure, classification, and evolution of the genus Saccharum. The application of fluorescence in situ hybridization using oligonucleotide probes significantly improved our understanding of the complex genomes of Saccharum species. This paper reviews the application and progress of cytogenetic techniques in Saccharum. Future applications of cytogenetics are discussed, as they could benefit both genomic studies and breeding of sugarcane as well as other plants with complex genomes. [ABSTRACT FROM AUTHOR]

In the scenario of unexpected climate patterns food security has become the highest priority around the globe. The decline in freshwater resources is of major concern for achieving stable agricultural productivity. Demand for vegetable oils is increasing globally but existential drought is responsible for the under production of important oilseed crops. In rapeseed and mustard, drought stimulates plants to down regulate or even stop normal metabolic pathways and activate the synthesis of stress responsive metabolites. These metabolites result in hormonal imbalance, disruption to tissues, reduction in oil contents and morphological changes in overall plant phenotype. Ultimately, optimal production of yield and biomass is compromised to ensure survival. To develop tolerance in existing genotypes of Brassica conventional breeding have provided promising outcomes, but further input from molecular breeding approaches offers rapid, targeted selection for favourable genotypes and thus an increased speed of variety development. Unprecedented advances in biotechnology have assisted the exploitation of drought stimulated mechanisms and engineering of the respective pathways to incorporate drought tolerance in innumerable Brassica species. This paper reviews the current and novel application of molecular breeding and biotechnology for producing drought tolerance in Brassica species with a major focus on ubiq- uitination and sumoylation regulatory pathways. [ABSTRACT FROM AUTHOR]

Brassica napus is an important cultivated oilseed crop famous for good quality oil (Canola oil) yet its production is insufficient to meet the domestic demands. One of the problems due to which reduction in yield occurs, is pod shattering at maturity and during harvesting. Enhanced inherent shatter resistance is the best solution for this problem. The phenotypic variation of such complex trait can be studied through Association mapping. The present study was based on delineation of marker-trait associations by using simple sequence repeats (SSRs) markers. A collection of 75 randomly selected most diverse lines, based on the results of previous experiment, was genotyped using 55 polymorphic SSRs covering whole genomes. The population structure and linkage disequilibrium (LD) was measured from the genotypic data after removal of minor alleles with P > 0.01, and marker trait associations were was also determined. Minimum 1 and maximum 4 SSRs were found to be highly associated with each trait studied. Important marker-trait associations found were days to 100% maturity with "Ra2A11", pod shatter percentage with "sNRA85", plant height with "sR94102" seed yield per plant with "PBCESSRJU15" and thousand seed weight with "sNRB35". These highly associated markers may effectively be used in Marker assisted breeding of Brassica napus. The SSR markers, found highly associated to various traits may be utilized in MAS of Brassica napus inbreeding programs to reduce varietal development time. [ABSTRACT FROM AUTHOR]

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Mean performance and heritability in morphological yield traits of eight cultivars (SLH-284, CIM-446, CIM-473, CIM-496, CIM-499, CIM-506, CIM-554 and CIM-707) of upland cotton (G. hirsutum) and their 56 F3 diallel populations were studied at University of Agriculture, Peshawar, Pakistan during 2011. The experiment was laid out in RCBD with triplicate replications. The analysis of variance showed highly significant variability among 8 × 8 F3 populations including their parents for all the studied characters except monopodia per plant which was found to have significant differences. Among parental genotypes, CIM-707 showed maximum performance for sympodia per plant, locules per boll, seeds per locule and seeds per boll. Among F3 populations, cross CIM-473 × CIM- 446 revealed superior performance in case of seeds per locule, seeds per boll, sympodia per plant and locules per boll which were found comparatively good for seed cotton yield per plant. Highest heritability was noticed for sympodia per plant (0.79) and locules per boll (0.77). Our findings further confirmed that F3 populations from SLH-284 × CIM-707, CIM- 473 × CIM-496, CIM-554 × CIM-707 and CIM-506 × CIM-499 were promising and performed better for various morpho-yield traits. Majority of the studied traits were highly heritable indicating that selection may lead to improvement in mean value of corresponding traits and thus may be used as guidance in future cotton breeding programs. [ABSTRACT FROM AUTHOR]