Morphogenesis, volume and number of hop (Humulus lupulus L.) glandular trichomes, and their influence on alpha-acid accumulation in fresh bracts of hop cones

The ESEM investigations revealed the morphogenesis of peltate glandular trichomes, which was divided into five phases. In phase one, new peltate glandular trichomes were initiated; in phase two, they were differentiated; in phase three trichomes grew vigorously; in phase four they were determined; in the fifth and final phase they came to maturity. Volume of glandular trichome during the different phases of morphogenesis varied from 0.25 ´ 10–2mm3 in phase 1, to 1.95 ´ 10–2mm3 in phase 5. More glandular trichomes are placed on the base of the adaxial side of bracts (average 7 mm–2) than on the base of abaxial side (average 5.8 mm–2). In this research, positive spearman\u27s rank order correlations were found between the average number of glandular trichomes and content of a-acids as well as between the average volume of glandular trichomes and content of a- acids

PLEIOTROPIC EFFECT OF Rht3 DWARFING GENE ON SOME TRAITS OF WHEAT (Tr. aestivum L. em Thell)

True-isogenic lines, differing only in the semi-dominant Rht3 dwarfing gene, were developed from the cross 'Tom Thumb x Bankuty 1201' during 17 years of continuous selection on heterozygous semi-dwarf plant. The effect of double (Rht3 Rht3 = full-dwarf), single (Rht3 rht3 =semi-dwarf), or no dwarfing gene (rht3 rht3 = tall) dosage on some plant, seed, and flour quality traits were observed in the isogenic lines during two years field experiment, planted by 'honey-comb design' at Kri`evci, Croatia. Significant main effect of Rht3 gene was in shortening of plant height by 54% and 28% in double and single gene dosage respectively. Full-dwarf genotype (Rht3 Rht3) had by 12% more heads/plant, but the other yield components as number of grains/head, and grain weight/head were lower by 25 and 28% respectively, resulting in significantly lower grain yield/plant (-27%). However, this also could be a secondary side effect of prolonged vegetation influenced by doubled Rht3 gene. There was no significant effect on flour protein content. Double gene effect was strong and significant for maximum dough viscosity measured by amylograph in BU (101%). In our environment full dwarf (Rht3 Rht3) has no agronomic value, but single gene dosage could be of commercial interest in hybrid wheat breeding

Hop pellets type 90: Influence of manufacture and storage on losses of α-acids

Hop pellets type 90 are the most frequent hop products used in brewing. They are usually manufactured by drying hop cones, temporary storage of dry and pressed cones, milling and pelletising. Other possibility is a complete integration of hop harvest, cone drying, milling and pelletising in continuous process without temporary storage of pressed cones. The paper deals with the losses of bitter substances (primary α-acids) during hop cones drying, their pelletisation by two manufacturing procedures and storage in different conditions. The results of this study show that integrated procedure of hop pelletising decreases the total loss of α-acids compared to the usual procedure. During storage of hop pellets (produced by integrated procedure) the highest decrease (loss) of α-acids content was observed in pellets stored at 21 °C in the presence of air and the lowest under inert atmosphere (N2) at 4 to 7 °C, respectively

Hop pellets type 90: ESEM studies of glandular trichomes morphological and structural changes during the different phases of hop processing

The results of this study show that the most usual damages of hop glandular trichomes are obtained on tunica of peltate glandular trichomes as well as cracking of bulbous glandular trichomes. In fresh hop cones any sorts of damage of glandular trichomes are obtained, on the other hand frequency of damaged hop glandular trichomes increase after drying (fi=0.08) and after pelletization of hop cones the structure of glandular trichomes is completely destroyed. Volume of hop glandular trichomes of dried hop cones is significantly smaller in the comparison with volume of glandular trichomes of fresh hop cones (D=0.544×10−2 mm3; P<0.01) and a phenomenon of shrinkage on tunica surface of peltate glandular trichomes of dried hop cones is also visible in comparison with the fresh one. The decrease in volume of hop glandular trichomes in dried hop cones is the result of dehydration of hop cones and consequently hops glandular trichomes during the drying process which cause shrinkage of peltate glandular trichomes. However, after pelletization the structure of hop glandular trichomes is completely destroyed