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Mean Yield (mean + yield)
Selected AbstractsForage and biomass feedstock production from hybrid forage sorghum and sorghum,sudangrass hybridsGRASSLAND SCIENCE, Issue 4 2008Brad Venuto Abstract As the bioenergy industry expands, producers choosing to shift current forage crop production to dedicated biomass crops can benefit from growing lower risk multipurpose crops that maximize management options. Hybrid forage sorghums (HFS) and sorghum,sudangrass hybrids (SSG) are capable of impressive biomass yields and tolerance to environmental stress. Multiple vegetative harvests (ratoon harvests) of sorghum are possible and there are photoperiod-sensitive sorghums that remain vegetative. However, the response of newer HFS and SSG cultivars to harvest management practices designed for forage or cellulosic feedstock production has not been fully investigated in all environments. The objectives of this study were to: (i) determine biomass production and quality characteristics of a genetically diverse range of HFS, SSG and sudangrass cultivars and evaluate their interaction with harvest system; and (ii) provide data to aid selection of sorghum cultivars for both forage and biofuel uses. Mean yield across all entries and years for a single late season harvest was 27.1 Mg ha,1 of dry matter per year. Mean total yield for a first harvest plus a ratoon crop was 25.5 Mg ha,1 of dry matter per year. However, entries varied for yield and interacted with harvest system. Mean caloric value was 16.5 Gj Mg,1 and modest differences were observed among cultivars evaluated. The best performing entry (cv. Tentaka) yielded 40.3 Mg ha,1 of dry matter for a single late season harvest, demonstrating the biomass potential of existing sorghum cultivars, specifically those possessing photoperiod- and/or thermosensitive genotypes. [source] Tall Fescue Adaptation to Low Nitrogen Fertilization in Relation to Germplasm Type and Endophyte InfectionJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 3 2008L. Pecetti Abstract Efficient crop growth with low nitrogen (N) application is becoming a requirement to face the concern on excessive N emission to the environment and the increasing cost of fertilizers. This study compared six natural populations and three improved varieties of tall fescue (Festuca arundinacea Schreb.) for dry-matter yield over 4 years under ordinary N fertilization (450 kg ha,1 in the 4 years) and very low N fertilization (only 40 kg ha,1 prior to sowing). Both endophyte-infected (EI) and endophyte-free (EF) forms of each accession were sown. On average, ordinary fertilization implied 30 % higher yield than very low fertilization and the EI germplasm outyielded the corresponding EF germplasm (+4.4 %). Mean yield of improved varieties was higher than that of natural populations under ordinary fertilization (P < 0.05), whereas the two germplasm groups did not differ under very low fertilization. Accession × N fertilization interaction was found among natural populations but not among varieties (P < 0.05). A few natural populations were top-yielding under very low fertilization and may be exploited, possibly in combination with endophyte infection, to select tall fescue varieties with enhanced performance under limited N application. [source] Barley adaptation and improvement in the Mediterranean basinPLANT BREEDING, Issue 6 2008A. Pswarayi Abstract To study barley adaptation and improvement in the Mediterranean basin, a collection of 188 entries comprising landraces and old genotypes and current modern varieties from the Mediterranean basin and elsewhere was tested on moisture-contrasted environments in seven Mediterranean countries, during 2004 and 2005 harvest seasons. The experimental design consisted of an unreplicated trial for all entries, augmented by four repeated checks to which a partial replicate containing a quarter of the entries was added. Best Linear Unbiased Predictions (BLUPs) representing adjusted genotypic means were generated for individual trials using a mixed model. BLUPs were used for genotype by environment interaction analysis using main effect plus genotype by environment interaction (GGE) biplots of yield ranked data and for comparisons of landraces, old and modern genotypes using analysis of variance. Mean yields ranged from near crop failure to 6 t/ha. Local landraces were better adapted to environments yielding below 2 t/ha, thus breeding has mostly benefited environments yielding above 2 t/ha where modern genotypes out yielded landraces and old cultivars by 15%. Current barley selection is leading to specifically adapted genotypes. [source] Evaluating Tripsacum -introgressed maize germplasm after infestation with western corn rootworms (Coleoptera: Chrysomelidae)JOURNAL OF APPLIED ENTOMOLOGY, Issue 1 2009D. A. Prischmann Abstract Maize (Zea mays L.) is a valuable commodity throughout the world, but corn rootworms (Chrysomelidae: Diabrotica spp.) often cause economic damage and increase production costs. Current rootworm management strategies have limitations, and in order to create viable management alternatives, researchers have been developing novel maize lines using Eastern gamagrass (Tripsacum dactyloides L.) germplasm, a wild relative of maize that is resistant to rootworms. Ten maize Tripsacum -introgressed inbred lines derived from recurrent selection of crosses with gamagrass and teosinte (Zea diploperennis Iltis) recombinants and two public inbred lines were assessed for susceptibility to western corn rootworm (Diabrotica virgifera virgifera LeConte) and yield in a two-year field study. Two experimental maize inbred lines, SDG11 and SDG20, had mean root damage ratings that were significantly lower than the susceptible public line B73. Two other experimental maize inbred lines, SDG12 and SDG6, appeared tolerant to rootworm damage because they exhibited yield increases after rootworm infestation in both years. In the majority of cases, mean yield per plant of experimental maize lines used in yield analyses was equal to or exceeded that of the public inbred lines B73 and W64A. Our study indicates that there is potential to use Tripsacum -introgressed maize germplasm in breeding programs to enhance plant resistance and/or tolerance to corn rootworms, although further research on insect resistance and agronomic potential of this germplasm needs to be conducted in F1 hybrids. [source] The effect of cutting and fish-orientation systems on the deheading yield of carpINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 9 2008Andrzej Dowgiallo Summary Applied research into carp-deheading yield indicated that the V-cut with two circular knives averaged 77.9%; the V-cut with one cup-type knife , 75.6%, and the straight cut at a 79° angle to the fish backbone , 77.4%. The yield averages for deheaded and gutted carp were 63.6%, 62.4% and 62.9%, respectively. Standard analysis of variance demonstrated that there were no statistically significant differences between the mean yields of these three deheading systems. Furthermore, the potential influence of the fish-orientation system in close connection with the cutting systems on the deheading yield was analysed. This indicated that, with the same yields, the straight-cutting system simplifies the precise orientation of the fish in relation to the cutting knives. [source] | |||||||||||||