Characterization of interspecific hybrids and backcross progenies from a cross between Oryza minuta and Oryza sativa.

Oryza minuta, a tetraploid wild relative of cultivated rice, is an important source for the genetic improvement. Interspecific hybrids were obtained from the cross of O. sativa L.

[Relationship of activation of Tos17 and rice adult plant resistance to bacterial blight].

to investigate whether rice adult plant resistance (APR) is related to activation of long terminal repeat (LTR) retroelements, polymorphism of LTR retroelemnts Tos17 are studied using SSAP (Sequence-Specific Amplification Polymorphism) in seedlings and adult plants of rice cultivar Wase Aikoku 3 inoculated with Xanthomonas oryzae pv. Oryzae, water and those untreated. Of 2000 fragments detected, 9 and 2 are activated in seedlings and adult plants induced by development, respectively; each 3 fragments are activated in seedlings and adult plants induced by pathogen, respectively.

Genetic analysis of the low critical sterility temperature point in photoperiod-thermo sensitive genic male sterile rice.

It has been a long haul but photoperiod- and thermo-sensitive genic male sterile (PTGMS) rice has not been freely used in hybrid rice production because there are two perplexing problems corresponding to the critical sterility temperature point (CSTP): the uncertainty of the CSTP segregating pattern and the instability of CSTP for every originally useful line. N5088S, the most widely commercialized japonica-type PTGMS line in China, also saw that its CSTP variants have been isolated but with all other agronomic characteristics unchanged. In this report we analyzed the genetic basis of CSTP, by employing the iterated expectation and conditional maximization (IECM) algorithm on four tiller-splitting-formed sets of seven generations from N5088S and its CSTP-variant H5088S, each set treated with one temperature regime.

[Effect of temperature on the fertility restoration of different two-line hybrid rice].

On the basis of the fertility observation of hybrids from Pei'ai 64S and Nongken 58S crossed with an indica variety Nanjing11 and japonica marker line FL235, respectively, The plant growth chambers were employed to expose the F2 plant individuals to such different day mean temperature as 24 degrees C, 27 degrees C and 30 degrees C during natural long hour daylight from July to August in Wuhan (30 degrees 27' N), with a view to analyzing the difference in the temperature sensitivity of fertility between the two kinds of different fertility-restoring genes for two years running. The results showed that, whether it was under long daylight and high temperature or under long daylight and middle temperature, the mean natural seed-set percent of F1 was higher than 68.75%, suggesting that Nanjing11 could completely restore the fertility of Pei'ai 64S.

Cloning and expression of VB12-independent methionine synthase gene responsive to alkaline stress in rice.

VB12-independent methionine synthase is present in higher plants, and catalyzes the methylation of C-homocysteine to form methionine, which is very important for methylation reactions and syntheses of polyamines and ethylene. Under the alkaline condition, using cDNA-RAPD method, a new VB12-independent methionine synthase gene has been cloned and characterized for the first time in rice in this study. The results exhibited that, the cDNA gene entailed 2740 bp, had single copy in the rice genome and encoded peptide of 765 amino acids, the peptide showed 92% and 83% identity with that from Mesembryanthemum cystallinum (U84889) and Cathararanthus roseus (X83499), respectively.