QTLs for Sugar Content of Stalk in Sweet Sorghum （Sorghum bicolor L.Moench）

High sugar content of sorghum stalk is an important factor in the sorghum silage production. To identify the genomic regions controlling sugar content and to develop molecular markers linked to sugar content in sweet sorghum, we used an F2：3 segregating population consisting of 207 individuals derived from a cross between a high sugar content inbred line, Early Folger, and a normal inbred line, N32B, for genetic linkage mapping and quantitative trait locus （QTL） analysis. We constructed a genetic linkage map spanning 983.5 cM based on a total of 327 markers comprising 31 restriction fragment length polymorphism （RFLP） markers, 254 amplified fragment length polymorphism （AFLP） markers, and 42 simple sequence repeat （SSR） markers. In the 20 linkage groups detected, 98.2% of markers aligned to the 10 linkage groups of sorghum. Variations in sugar content at different growth stages and among internodes suggested that the sugar content of middle internodes is stable and suitable for measuring at early dough stage. The broad sense heritability （hB0 of sugar content was 0.64 and 0.62 estimated from the data of F3 families and each parent in 2003 and 2004. We identified one and two QTLs accounting for 22.2 to 25.0% of phenotypic variance using simple interval mapping method in 2003 and 2004, respectively. These two QTLs showed a negative additive effect, and over-dominance effect. A QTL on LG-D was detected in both two years. Above results will be help us to understand the genetic mechanism of sugar content in sorghum and the QTL detected in this study might be useful in the improvement of sugar content by marker-assisted selection.     

Cell Ultrastructure of Kiwifruit （Actinidia chinensis） Shoot Tips During Cryopreservation

The changes in the cell ultrastructure of in vitro cultured shoot tips from dwarf genotype of kiwifruit （Actinidia chinensis Ganmi 5） during cryopreservation were investigated. Shoot tips were preserved in liquid nitrogen using vitrification, and the cell ultrastructure was examined using transmission electron microscopy （TEM）. The regular ultrastructure of the cell wall, cell membrane and nucleus of shoot tips could be damaged during the freezing and thawing associated with preservation using liquid nitrogen. The cell plasmolysis was increased and freezing tolerance was improved after precultufing and dehydrating in a preservation and vitrification solution （PVS2） （30% glycerol （Gly）＋ 15% ethylene glycol （EG）＋ 15% dimethylsulfoxide （DMSO） ＋ 0.4 mol L^-1 sucrose）. The structure of some cells with low degree of injury and reversible damage was similar to that of the control and they could undergo normal cell division and differentiation. Besides, they could recover automatically and regenerate after their reculture.     

Effect of traditional methods of processing on the electrophoretic patterns of faba bean water soluble proteins

A number of national dishes are prepared from the dry seeds of faba bean by soaking, germination (nabet), cooking (bisara and medammis) or frying a dough (falafel). Soaking (12 h) decreased the intensity of bands in the standard PAGE and increased the charge heterogeneity of neutral proteins in PAGIF. Germination (24 or 60 h) changed the patterns for esterases, peroxidases and amylases, but not for phosphorylases. The charge distribution of proteins was markedly changed in the basic region. Roasting did not affect the distribution in standard PAGE. All bands in the basic region of PAGIF disappeared. High MW-proteins wre degraded to low MW-proteins as seen in SDS-PAGE. The cooking broth and the cooked beans of nabet soup and medammis had more or less similar patterns in the standard PAGE. The broth of nabet soup had larger number of low MW-proteins than the bean extract in SDS-PAGE. Bisara proteins showed almost the same patterns as the corresponding proteins of the cooking broth of nabet soup. Falafel proteins showed patterns very similar to that obtained from roasted beans in the SDS-PAGE. PAGIF gave a different but characteristic charge distribution for falafel.