[Genetic analysis of gelatinization temperature in rice via microsatellite(SSR) markers].

Rice gelatinization temperature is an important character contributing to cooking quality. Here the inheritance of gelatinization temperature (GT), which was represented by alkali spreading value (ASV), was reported. Two parents, Balilla (japonica variety) and Nantehao (indica variety), which were significantly different on GT-ASV, were selected to construct a backcross population Balilla/Nantehao//Balilla containing 142 individuals. And ASV was investigated in the population, a continuous distribution with two obvious peaks was observed. It indicated that GT-ASV was controlled by one major gene, also modified by some minor genes. In order to map the major and minor genes and estimate the effects of genes. A total of 119 SSR markers were employed to construct a linkage map; further a genome-wide detection was carried out by interval mapping method. The results showed that 6 QTLs were detected, of which, qASV6-1 located on chromosome 6 was a major gene with 87.6% variance explained, and alleles from parent Nantehao could decrease the value. It shoud be the same locus as the alkali degeneration gene (alk). The other QTLs (qASV2, qASV3, qASV6-2, qASV9, and qASV11) all belong to minor genes, which were located on chromosome 2,3,6,9 and 11, respectively. In two parents, they carried the positive and negative alleles simultaneously. These results will be helpful for rice quality breeding and improvement.

[A genetically modified japonica restorer line, C418-Xa21, and its hybrid rice with bacterial blight resistance].

The cloned bacterial blight (BB) resistance gene Xa21 was transferred into C418, a major restorer line of japonica hybrid rice in China, using an Agrobacterium-mediated system. The integrated single copy of transgene displayed a 3:1 segregation ratio in T1 generation in PCR and resistance analyses. The transgenic homozygous C418-Xa21 lines were selected in T2 generation through PCR and resistance analyses. The selected transgenic restorer lines were then crossed with a commonly used sterile line, TijinA, to produce Xa21 transgenic hybrid rice. Molecular analysis revealed that the produced hybrid rice, named as Tiyou418-Xa21, inherited the transgene. Both C418-Xa21 and Tiyou418-Xa21 plants displayed high resistance with a broad spectrum to Xoo races and maintained their normal elite agronomic characters. We also observed that the resistance level of Tiyou418-Xa21 was obviously higher than that of C418-Xa21 which may be attributed to their differences in genetic background. The propagation of this BB resistant hybrid variety with the transgene Xa21 with extend hybrid rice production in north China.

[Re-analysis of wide compatibility in rice].

Utilization of heterosis between rice subspecies has fascinated rice breeders for several decades. One of the main obstacles is the hybrid sterility in the F1 populations of subspecies crosses in rice. Wide compatibility varieties are considered to an important way to overcome the problem. But the genetics of the wide compatibility is controversial. This paper dealt with the problem through three kinds of triple crosses in which a wide compatibility variety, Ketan Nangka, was involved. Pollen fertility, spikelet fertility and the correlationship between the two fertilities were analyzed in the three kinds of triple crosses. The results suggested that male and female sterilities existed in indica-japonica hybrids at the same time, while the contribution of male sterility to spikelet fertility varied from cross to cross; The characteristic of wide compatibility in different triple crosses was coordinated with the hybrid sterility between the indica and japonica test varieties used; Ketan Nangka possessed the wide compatibility genes on the loci in which the male and female sterilities between the test varieties were involved; The genetics of wide compatibility gene S-5 fitted to one locus sporo-gametophytic interaction model.

[RFLP analysis of the effect of wide compatibility genes in Aus variety 'Dular'].

RFLP markers were employed to test whether the individuals possess wide compatibility genes (WCGs) in the progenies of Dular, which is one of the typical wide compatibility varieties in ecotype Aus rice. Meanwhile the characteristics of WCGs were also analysed. The results are shown as follows: (1) the effect of WCG at S-5 locus is better than the others, (2) the combination of different wide compatibility loci is obviously effective in increasing the spikelet fertility, (3) intraallelic interaction can cause japonica macrospore abortive, while interallelic interaction has some effects in fertility expression.

[In vivo antitumor activity of mitoxantrone and the flow cytometric analysis of its influence on cell cycle transition--comparison with doxorubicin and aclarubicin on ascitic hepatoma AH109A cells].

Mitoxantrone was compared with doxorubicin and aclarubicin of its in vivo antitumor activity and influence on cell cycle transition by use of rat ascitic hepatoma AH109A. Antitumor activity determined by the cell growth curve was similar in mitoxantrone and doxorubicin, but the sensitivity of AH109A to aclarubicin was lower than that to the other two drugs. Doxorubicin and mitoxantrone showed all phase arrests with 1/10 of maximally tolerated dose (MTD), and with lower concentrations a strong arrest at G2 phase was observed, thus, mitoxantrone appeared to have a similar antitumor activity on AH109A to that of doxorubicin. Aclarubicin, with 1/10 MTD, demonstrated only a transient arrest at G2 phase, cells arrested at G2 phase entering into the next phase. With below 1/10 MTD, there was no appearance on histograms, and the influence on AH109A cell cycle transition by aclarubicin was considered to be little in comparison with doxorubicin and mitoxantrone.