The version of microevolutionary relationships between biotypes close to Elymus caninus (Poaceae) according to the sequencing of the nuclear gene GBSS1 (waxy)

A comparative study of the sequences of the GBSS1 gene fragment in accessions of species close to Elymus caninus:E. prokudinii, E. viridiglumis, E. goloskokovii, as well as a number of morphologically deviating forms (MDF) from the territoryof Russia and Kazakhstan was carried out. The StH-genomic constitution was established or confirmed in all studied taxa andMDF, and the microevolutionary relationships between species were assessed by constructing separate NJ dendrograms based onexons and introns together and exons only. Differences in the location of Y subgenomes in reference StY-genomic species on twotypes of constructed dendrograms were noted. Possible evolutionary reasons for these differences are discussed. A characteristicfeature of all taxa close to E. caninus is the presence of only St2clones of the St subgenome, which are closer in composition tothe North American ancestral line Pseudoroegneria spicata than to the Asiatic line ascending to P. strigosa. The reference Polishaccession E. caninus can_5274 is farthest from the Asian accessions in the St2subgenome, but closer to the diploid carrier ofthe St genome P. spicata. According to the levels of differentiation of the H subgenome, all putative relatives of E. caninus havevariants of the H1subgenome around the Asian diploid host Hordeum jubatum, while being divided into two distinct subgroups.Only the accessions of four reference species gravitate towards the North American species Hordeum californicum – the carrierof the H2gene variant. It should be noted that the gene variants of the Ural endemic E. uralensis are close to the main group ofE. caninus accessions in both subgenomes. Together with the results of sexual hybridization, this fact gives grounds to considerE. uralensis as closely related to the main group of taxa deserving the intraspecific rank of E. caninus s. l.

Review: Rice Blast Disease

Rice blast caused by Magnaporthe grisea is the major damaging disease in nearly all rice growing nations. Economically relevance with 60 percent of total population of world depending on rice as the main source of calories, may have destructive effects of the disease, however, this pathogen has developed into a pioneering model system for researching host-pathogen interactions. The disease outbreak depends on the weather and climatic conditions of the various regions. The disease's occurrence and symptoms vary from country to country. Susceptible cultivars cause huge rice production loss in yield. The principal cause of resistance breakdown in rice against rice blast disease is pathogenic variability. During sexual hybridization, pathogenic changes may provide evidence of pathogenic variation found at the asexual stage of the fungus. The virulent pathotypes cause severe disease incidence. Only through pathogenicity research the pathotypes can be determined using a collection of different rice varieties that are usually different carrying various resistance genes. Rice breeders now have a number of resistant genes however, most of the breeding programs emphasized upon monogenic resistance. Genetic heterogeneity of M. grisea should be taken into account when screening blast resistant rice genotypes through morphological analysis, pathogenicity and molecular characterization. Knowledge on the virulence of the rice blast and host resistant is essential for managing the disease. Cultivation of resistant varieties with chemical control is highly effective against blast pathogens.

Rubus glaucus Benth.: morphology and floral biology aimed at plant breeding processes

Rubus glaucus is widely distributed throughout the three mountain ranges of Colombia, where the blackberry growers have highlighted the need to standardize the supply of planting material, starting with plant breeding schemes that lead to more productive varieties with morphological characteristics that ease agricultural activities. Plant breeding activities have improved by considering the pollination mechanisms of plants. The implementation of controlled sexual hybridization depends on these pollination mechanisms, and several plant breeding methods have been adapted to crop pollination patterns. Morphological characteristics and studies on the floral biology of R. glaucus Benth were conducted to improve plant breeding processes. In addition, a study on pollen viability and stigma receptivity were performed. The reported morphological characteristics of R. glaucus enabled characterization of its flowers as complete and perfect with a regular, actinomorphic, perianth heterochlamydeous, dialipetalous, and dialisepalous structure. Meanwhile, the evaluation of different collection times for pollen viability revealed significant differences. The highest pollen viability occurred at 10:00 am, followed by 9:00 am. Qualitative evaluation of stigma receptivity led to the conclusion that the highest stigma receptivity is at anthesis at 12:00 m.

Plant Hybridization as an Alternative Technique in Plant Breeding Improvement

For ages, plant breeders have relied on the genetic variability that results from sexually crossing plants within the same species. However, the variability that exists within species populations is inadequate, hence the need to exploit desirable traits of interest in distantly related or even unrelated plants through hybridization techniques. Hybridization can be categorized into two; sexual and somatic. Sexual hybridization, also referred to as wide or distant hybridization involves combining two genomes from different parental taxa through pollination, either naturally or by induction. Somatic hybridization involves the fusion of somatic cells instead of gametes, which highly depends on the ability to obtain viable protoplasts and eventually differentiate them to whole plants in vitro. The impacts of hybrids can either be positive or negative. Among the positive attributes of hybrids that have been exploited is heterosis, which results either from dominance, over-dominance or epistasis. Negative ones include sterility, arrested growth of the pollen tube and embryo abortion. To overcome these problems, chromosome doubling, the use of hormones such as 2, 4-Dichlorophenoxyacetic acid (2, 4-D) and embryo rescue have been employed to overcome sterility, arrested growth of pollen tubes and embryo abortion respectively. After the development of hybrids, different hybrid identification techniques have been used to test them such as the use of molecular and morphological markers, cytogenetic analysis and fluorescent in situ hybridization. The use of hybridization techniques in plant improvement remains a vital tool to cross species barriers and utilization of important attributes in unrelated crop plants which could not have been achieved through conventional techniques of plant breeding.

Fluorescence-based approach for the effective development of industrial Saccharomyces cerevisiae strains

The laboratory evolution based on sexual hybridization – haploids breeding – is a powerful approach to study and develop Saccharomyces cerevisiae strains applied to the production of renewable fuels and chemicals. In this context, we developed a simple and efficient method based on reporter proteins expression and fluorescence-activated cell sorting (FACS). Exploring the natural genetic variability of two industrial Brazilian strains we obtained haploids showing superior biomass production under tree industrially relevant stress condition. In conclusion, this approach enables the isolation of an unlimited number of recombinants haploids requiring minimal and transient engineering, providing a powerful tool for create new superior hybrids through breeding, map genes related to industrially relevant traits, improvement of commercial strains and development of new ones.

Application of somatic hybridization for the improvement of horticultural crops

<p>Somatic hybridization (SH) using protoplast fusion is a promising tool to produce symmetrical and asymmetrical polyploidy somatic hybrids in many agricultural crops. The technique of SH could facilitate conventional breeding by providing of novel lines so as to use them as elite breeding materials in conventional crosses for both scion and rootstock improvement. Further, SH can overcome those problems associated with sexual hybridization viz., sexual incompatibility, nucellar embryogenesis, and male/female sterility. Successful exploitation of SH in horticultural crops mainly comes from transfer of resistance genes for biotic and abiotic stresses from related species in several horticultural crops, <em>viz</em>., citrus, potato, brinjal, tomato, mango, avocado, banana, strawberry, pear, cherry etc. Unlike transgenic technology, SH is not affected by legal formalities and able to transfer uncloned multiple genes. However, certain boundaries and limitations of SH restricts its use over sexual hybridization but, envisage of new genomic technologies providing better insight into the plant genomes will increase the potentiality of SH in betterment of agriculture.</p>