Genetic Analysis and Mapping of Genes Involved in Fertility of Pingxiang Dominant Genic Male Sterile Rice

Pingxiang-dominant genic male sterile rice （PDGMSR） was the first dominant genic male sterile mutant identified in rice （Oryza sativa L.）, and the corresponding dominant genic male sterile gene was designated as Ms-p. The fertility of PDGMSR can be restored by introduction of a dominant epistatic fertility restoring gene in some rice varieties. In the present study, E823, an indica inbred rice variety, restored the fertility of PDGMSR, and the genetic pattern was found to be consistent with a dominant epistatic model, therefore, the dominant epistatic fertility restorer gene was designated as Rfe. The F2 population from the cross of PDGMSR/E823 was developed to map gene Rfe. The F2 plants with the genotypes Ms-pMs-pRferfe or Ms-pms-pRferfe were used to construct a fertile pool, and the corresponding sterile plants with genotypes Ms-pMs-prferfe or Ms-pms-prferfe were used to con- struct a sterile pool. The fertility restoring gene Rfe was mapped to one side of the microsatellite markers RM311 and RM3152 on rice chromosome 10, with genetic distances of 7.9 cM and 3.6 cM, respectively. The microsatellite markers around the location of the Ms-p gene were used to finely map the Ms-p gene. The findings of this study indicated that the microsatellite markers RM171 and RM6745 flanked the Ms-p gene, and the distances were 0.3 cM and 3.0 cM, respectively. On the basis of the sequence of rice chromosome 10, the physical distance between the two markers is approximately 730 kb. These findings facilitates molecular marker-assisted selection （MAS） of genes Ms-p and Rfe in rice breeding programs, and cloning them in the future.

Dominant Gene cplsr1 Corresponding to Premature Leaf Senescence Resistance in Cotton (Gossypium hirsutum L.)

Cotton （Gossypium hirsutum L.） premature leaf senescence-resistant inbred XLZ33 and senescence- susceptible inbred lines XLZ13 were selected and crossed to produce F1, Ft-reciprocal, F2 and BCl generations for evaluation of leaf senescence process and inheritance. The results showed that leaf senescence processes for XLZ13 and XLZ33 were obviously different and leaf senescence traits could be distinguished between the two parents at particular periods of cotton growth. Inheritance anlysis for the cotton premature leaf senescence resistant trait further showed that the segregation in the F2 fit a 3：1 ratio inheritance pattern, with resistance being dominant. The backcross of F~ to the susceptible parent produced a 1：1 ratio, confirming that cotton premature leaf senescence resistant trait was from a single gene. The single dominant gene controlling cotton premature leaf senescence resistance in XLZ33 was named as cotton premature leaf senescence resistance 1, with the symbol cplsrl.

Identification and Gene Mapping of Completely Dominant Earliness in Rice

The completely dominant earliness was identified in a genie male-sterile and early maturing indica line 6442S-7. F1 progenies from 6442S-7 crossed with thirteen various types of medium- or late-maturing varieties, shared the same heading date as 6442S-7. The segregation of heading date in the F2 and B1F1 populations showed that the earliness of 6442S-7 is mainly controlled by two dominant major genes. The local linkage map of one dominant earliness gene harbored in 6442S-7 was constructed with F2 population and four kinds of molecular marker techniques. The results showed that the gene was located between a RFLP marker C515 and a RAPD marker OPI 11.557 on the terminal region of short arm of rice chromosome 3, 10.9cM and 1.5cM from C515 and OPI11.557, respectively. The genetic distances from the target gene to two SSR markers, RM22 and RM231, and one AFLP marker, PT671, were 3.0, 6.7 and 12.4 cM, respectively. This gene, being identified and mapped first, is designated tentatively as Ef-cd(t). As a new genetic resource of completely dominant earliness, 6442S-7 has splendid future in rice improvement.

Isolation, Identification and Earliness Effect Analysis of Rice Dominant Earliness Gene Ef-cd

Ef-cd gene is a dominant earliness gene located on the short arm of rice chromosome 3. In this paper, through continuous backcross, self-pollination and molecular marker assisted selection, individual Ef-cd gene was isolated and its nearly isogenic lines were constructed by using early-maturing indica line 6442S-7 as the donor parent, and by using latematuring indica line Minghui 63 （MH63）, Shuhui 881 （SH881） and Shuhui 527 （SH527） as the recurrent parents （genetic background）, respectively. Further, it was found out that Ef-cd gene could generally advance rice to head 11-14 d earlier. So, it was considered that Ef-cd gene played an important role in rapid developing early-maturing and super high-yielding rice varieties.

Genetic Analysis of the Resistance in Six Newly-bred Rice Varieties to the Whitebacked Planthopper,Sogatella furcifera

The paper reports the study on resistance in 6 newly-bred rice varieties, such as Nongxiang 16 and 9234, to the whitehacked planthopper, Sogatella furcifera. In crossing with the susceptible Taichung Native 1 (TN1), the resistance of their F1 and F2 populations and the back-crossed BC1F1 populations have been evaluated. The resistance to 5. furcifera in Zhenongda 6022, 9234 and Zhongjian 96-3 was controlled by a single dominant gene, and by a single recessive gene in Nongxiang 16, R40 and Shuhui 881, respectively. These varieties possessed good agronomical characteristics and could be used in further rice breeding and rice production.

An Improved GA for Combinational Logic Expressions

This paper discusses complete binary trees as chromosomes of Genetic Algorithm (GA), and proposes the concept of dominant and recessive genes. On the base of it, a new crossover operator with the selective ability was designed. Finally experimental results are presented.

Genetic Analysis and Mapping of the Dominant Dwarfing Gene D-53 in Rice

The dwarfing gene D-53 Is one of a few dominant genes for dwarfing In rice （Oryza satlva L.）. In the present study, our genetic analysis confirmed that mutant characteristics including dwarfing, profuse tlllerlng, thin stems and small panicles are all controlled by the dominant D-53 gene. We measured the length of each Internode of KL908, a D-53-carrylng line, and classified the dwarfism of KL908 Into the dn-type. In addition, we measured elongation of the second sheath and a-amylase activity In the endosperm, and we characterized KL908 as a dwarf mutant that was neither glbberelllc acid-deficient nor glbberelllc acid-Insensitive. Using a large F2 population obtained by crossing KL908 with a wild-type variety, NJ6, the D-53 gene was mapped to the terminal region of the short arm of chromosome 11, with one simple sequence repeat marker, Ds3, co-segregating, and the other, K81114, located 0.6 cM away.