Authors:A.O. Kolawole, A. Menkir, E. Blay, K. Ofori, and J.G. Kling
Two improved tropical maize composites, TZL COMP3 and TZL COMP4; representing complementary heterotic pools have been subjected to four cycles of reciprocal recurrent selection (RRS) for two decades to enhance varietal cross performance. The objectives of this study were to evaluate the effect of selection on genetic gain in heterosis for grain yield and other agronomic traits of these composites. Ten parental populations representing the C0 to C4 of each composite and their crosses plus a varietal check were evaluated in a trial at eight environments in Nigeria. Grain yield of the varietal crosses increased with selection by 3.1% cycle–1. Mean grain yields of the C4 × C4 varietal cross exceeded that of a popular improved reference variety by 23%. Selection also reduced anthesis-silking interval, improved ear characteristics, phenotypic appeal and resistance to foliar diseases. Mid-parent heterosis (MPH) increased from 4% at C0 × C0 to 24% at C4 × C4. The average rate of genetic gain in heterosis for grain yield in population crosses was 3.1% possibly because of presence of non-additive gene effects. The results of our study present the potential usefulness of the advanced selection cycle as sources of diverse inbred lines with improved combining ability as well as improved varietal crosses that can be multiplied and deployed in areas with limited market access.
Authors:Soňa Jantová, Silvia Letašiová, Marica Theiszová, and M. Palou
Kim, H. W., Noh, Y. J., Koh, Y. H., Kim, H. E. (2003) Enhanced performance of fluorine substituted hydroxyapatite composites for hard tissue engineering.
J. Mater. Sci. Mater. Med. 10
Kim H. E
Authors:Neda Haddadderafshi, Tímea Borbála Pósa, Gábor Péter, László Gáspár, Márta Ladányi, Károly Hrotkó, Noémi Lukács, and Krisztián Halász
Endophytic fungi have the potential to protect their host plants in stress situations. Characterizing the ecology and complex interaction between these endophytes and their host plants is therefore of great practical importance, particularly in horticultural plants. Among horticultural plants, fruit trees form a special category because of their longevity and because they are composites of rootstock and scion, which often belong to different plant species. Here we present the first characterization of culturable endophytic fungal community of sweet cherry. Samples from the Hungarian cultivar ‘Petrus’ grafted on 11 different rootstocks were collected in autumn and in spring in a bearing orchard and the dependence of colonization rate and endophyte diversity on rootstock, organ and season was analysed. On the basis of their ITS sequences 26 fungal operational taxonomic units were identified at least down to the genus level. The dominant genus, comprising more than 50% of all isolates, was Alternaria, followed by different Fusarium and Epicoccum species. We observed some organ-specificity amongst endophytes, and organs showed more sizeable differences in colonization rates and endophyte diversity than rootstocks. Most dynamic endophyte populations, strongly influenced by environmental conditions and crop management, were observed in leaves. The potential of selected endophytes to confer protection against Monilinia laxa was also analysed and 7 isolates were found to inhibit the growth of this pathogen in vitro.
Authors:W. Myers, J. Bishop, R. Brooks, and et al.
Indexing and mapping of co-occurrence for multiple species is central to many analyses of conservation needs, ecosystem health, and community composition. Species richness is often used because of its simplicity and interpretability, but a variety of ecologically based weighting schemes for species have been developed for special purposes such as determining biotic integrity. This work is concerned with indexing a balance between common and uncommon species for preliminary assessments of conservation needs. A Regional Habitat Importance Index is constructed in a manner that provides joint ordering of species and landscapes. The index lends emphasis to species having a scarcity of habitat over a region, low representation in conservation areas, and shortage of opportunity for expanding protection. Application of the index is illustrated for mammals and birds in the context of GAP Analysis for the state of Pennsylvania, USA.
Authors:Elizabeth M. Marlowe, Peter Gohl, Michael Steidle, Rodney Arcenas, and Carolin Bier
agreement (PPA). A composite reference (CR) was used to determine if the TV results from the cobas® TV/MG were considered true positive or true negative to calculate the sensitivity and specificity. The CR was composed of Aptima TV and the TV result of the
Doubled haploidy breeding via wide hybridization has been used in durum wheat haploid production for creating homozygosity in the shortest possible time. Post pollination treatment with hormones is a key factor for inducing haploid embryos in durum wheat wide crosses. An intergeneric hybridization experiment was carried out in seven durum wheat genotypes using Imperata cylindrica and two composites of Maize viz., Bajaura Makka and Early Composite, as pollen sources. The pollinated spikes were injected with 2,4-Dichlorophenoxyacetic acid (2,4-D) in five different concentrations i.e., 100, 150, 200, 250 and 300 ppm, for three consecutive days at 24, 48 and 72 hrs after pollination. Analysis of variance revealed that the five concentrations of 2,4-D significantly differed in their ability to induce haploid embryos and 2,4-D at 250 ppm was found to be most effective in durum wheat haploid production through wide hybridization. The highest frequency of embryo carrying seeds was recorded to be 65.75 and 36.73 percent, at 250 ppm with I. cylindrica and Bajaura Makka, respectively in first cropping season. During second season, embryo formation frequency was observed to be maximum, 70.69, 32.84 and 27.59 percent, at 250 ppm 2,4-D with all three pollen sources, viz., I. cylindrica, Bajaura Makka and Early Composite, respectively.
Phenoloid contents were detected, examined and compared with each other from seven composite species (Inula ensifolia L., I. salicina L., I. spiraeifolia L., I. britannica L., I. conyza DC., Centaurea scabiosa L., C. micranthos S. G. Gmel.). The six test solutions were the followings: apigenin, quercetin, hyperosid, chlorogenic acid, caffeic acid and rutin. There were significant differences between ray and disc florets from both quantitative and qualitative results, and the species with more significant insect visiting (Inula ensifolia, I. salicina, I. spiraeifolia) have got quantitative dominance.
Authors:K. Wajdzik, G. Gołębiowska, M. Dyda, K. Gawrońska, M. Rapacz, and M. Wędzony
The increasing economic importance of triticale (×Triticosecale Wittm.) makes this synthetic hybrid cereal an interesting object of genetic studies. Genomic regions (QTL) of morphological winter triticale traits were determined using the mapping population of 89 doubled haploids lines (DHs) developed from F1 hybrid of cv. ‘Hewo’ and cv. ‘Magnat’ accompanied with the genetic map consisting of 20 linkage groups assigned to the A (7), B (7), and R (6) genomes (total of 3539 DArT, SNP-DArT and SSR markers, length of 4997.4 cM). Five independent experiments were performed in the field and greenhouse controlled conditions. A total of 12 major QTLs located on 2B, 5A, 5R, and 6B chromosomes connected to the stem length, the plant height, the spike length, the number of the productive spikelets per spike, the number of grains per spike, and the thousand kernel weight were identified by a composite interval mapping (CIM).