Koeficijenti korelacije morfološko-produktivnih osobina vrsta roda Sorghum

Objective of the research were phenotypic and genetic correlation coefficients of three species of Sorghum genus - forage sorghum S. bicolor Moench. (genotype NS-Džin), Sudan grass S. sudanense L. (genotype Zora) and interspecies hybrid S. bicolor x S. sudanense (genotype Siloking). Studies were carried out on samples of plant material from the first cut. The following morphological-productive traits were studied: plant height, number of leaves per plant, mass of leaves on the stem, average stem mass and yield of green biomass. In the analysis of genetic and phenotypic coefficients, differences depending on the impact on studied morphological-productive traits are observed. The highest value of the stem height was recorded in Sudan grass (2.281 m), as well as number of leaves per plants (7.917). The greatest mass of leaves per plant was established in forage sorghum (49.05 g), and the highest average stem mass was recorded in interspecies hybrid plants (80.798 g). Variation of morphological-productive indicators per species was significant and very significant. Coefficients of simple correlations indicate the presence of very strong to almost complete, statistically very significant positive correlations, so these effects were expected. Plant height and number of leaves were not directly but indirectly statistically significant to yield of green biomass and varied from insignificant and very weak to sporadically medium strong and statistically significant.Predmet istraživanja ove studije su fenotipski i genetički koeficijenti korelacije tri vrste roda Sorghum, i to krmni sirak S. bicolor Moench. (genotip NSDžin), sudanska trava S. sudanense L. (genotip Zora) i interspecies hibrid S. bicolor x S. sudanense (genotip Siloking). Ispitivanja su vršena na uzorcima biljnog materijala iz prvog otkosa, Proučavane su sledeće morfološko-produktivne osobine: visina biljke, broj listova po biljci, masa listova na stablu, prosečna masa stabla i prinos zelene biomase. Analizom genetičkih i fenotipskih koeficijenata uočavaju se razlike i zavisnosti u delovanju na ispitivane morfološko-produktivne osobine. Najveću vrednost visine stabla imala je sudanska trava (2,281 m), kao i broj listova po biljci (7,917). Najveća masa listova po biljci bila je u krmnog sirka (49,05 g), a najveću prosečnu masu stabla imale su biljke interspecies hibrida (80,798 g). Variranja ovih morfološko-produktivnih pokazatelja po vrstama bila su signifikantna i vrlo signifikantna. Koeficijenti prostih korelacija ukazuju na postojanje vrlo jakih do skoro potpunih, statistički vrlo značajnih pozitivnih veza, ovakvi efekti su se mogli očekivati. Visina biljke i broj listova nisu bili direktno statistički značajni na prinos zelene biomase, ali indirektno jesu i varirali su od beznačajnih i jako slabih do sporadično srednje jakih i statistički značajnih

Effects of nitrogen and harvesting time on chemical composition of biomass of Sudan grass, fodder sorghum, and their hybrid

The subject of this study is 2-year variability research (2007 and 2008) of the chemical composition of naturally dried biomass samples of 3 different sorghum species, which are widely used in the southeast Balkans. Samples of Sudan grass Zora, fodder sorghum NS-Dzin, and their hybrid Siloking were examined based on the quantity of used nitrogen and the harvest time. Plants were grown in the experimental field of Radmilovac (property of the Faculty of Agriculture in Belgrade) in a randomized block, split-split plot design with 3 replications for 2 years. Naturally dried biomass with the highest amount of total proteins was obtained by mowing during the stem elongation phase (plant height, 100-120 cm). By subsequent mowing in the tasseling phase, the amount of total proteins and mineral substances in the biomass decreased, while the amount of carbohydrates and cellulose significantly increased. The content of lipids in the samples tested differed depending on the cultivar, but this variation was not statistically significant. By increasing the intensity of plant nitrogen nutrition, the total protein content in the tested samples was increased. Due to the large amounts of nonprotein nitrogen compounds, the fraction of digestible proteins did not increase. According to the established chemical composition of the silage sorghum hay, the total digestibility of nutritive components of the tested samples was determined to be satisfactory, above 51%. The highest quality biomass was obtained by mowing the hybrid of sorghum and Sudan grass during the stem elongation phase. The most suitable nitrogen dose of 80-120 kg and harvest during the tasseling period were the best for all 3 cultivars

Acid and Temperature Treatments Result in Increased Germination of Seeds of Three Fescue Species

Efficient germination of fescue seeds is essential for successful establishment of meadows and pastures. This research was conducted to ascertain the effects of various acid and temperature treatments on seed germination in three fescue species: Festuca rubra, F (mina, and E pratensis. Seeds from different cultivars, populations, or lots were exposed either to four concentrations of sulfuric acid at three different time intervals (12 treatments) or six different temperatures at three different time intervals (18 treatments). Despite all belonging to the genus Festuca, the seed from different species responded differently to the treatments. The three optimum treatments for E rubra seed involved soaking in a 75% solution of sulfuric acid for 20 minutes (improved the germination rate by 19%), soaking in a 50% solution of sulfuric acid for 30 minutes (improved the germination rate by 18%) and exposure to either 60 degrees C or 70 degrees C for 90 minutes (improved the germination rate by 17%). For F. ovina seed, optimal treatments included soaking seeds for either 10 or 20 minutes in a 50% sulfuric acid solution (both treatments improved germination rates by 13%) or exposing seeds for 30 minutes in a 25% sulfuric acid solution and 80 degrees C for 60 minutes (improved germination rate by 12%). Two optimal treatments were identified for F. pratensis seed. Whereas the first involved soaking the seeds in a 75% sulfuric acid solution for 30 minutes (improved germination rates by 22%), the second involved either exposing the seeds to 90 degrees C for 90 or 60 minutes, or exposing the seeds to 80 degrees C for 90 minutes (improved germination rate by 21%). Our findings indicate that if fescue seed is to be sown during the autumn (two to three months after seed collecting), treating it with acid and temperature can significantly enhance its germination