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【Objective】The present paper aimed to illustrate the potential utilization of the gene of resistance to bacterial blight and bacterial leaf streak, so as to provide reference for enriching genetic base of rice breeding.【Method】A total of 102 rice cultivars were used to screen by molecular marker for the gene xa5, which mediated the resistance for both for resistance to bacterial blight and bacterial leaf streak. The parents carrying xa5 gene and having good resistance to bacterial blight and bacterial leaf streak were used as resistant sources to cross with susceptible cultivated rice. Through pedigree method and molecular marker-assisted selection（MAS）, elite hybrid rice restorer lines were cultivated. The excellent restorer lines and sterile lines were combined with strong heterosis combinations to analyze the resistance and comprehensive agronomic traits of strong heterosis combinations.【Result】A total of 17 cultivars were screened, which carried xa5 gene from 102 rice germplasm resources（materials）. Among these cultivars, DP3, IRBB5, N36, N776, N777, N779 and P89 were well resistant to both bacterial blight and bacterial leaf streak. An elite line Y240-1 was selected from the cross between DP3 and 9311. Moreover, 998 R was crossed with elite individual Y240-1. With molecular MAS, an elite restorer line Yexiangzhan with xa5 was developed from the cross of 998 R and Y240-1, after multiple generations of selfing. Yexiangzhan was combined with sterile line Pingfeng A to produce an elite hybrid cultivar Pingfengyouxiangzhan, which showed higher resistance to bacterial blight and bacterial leaf streak in comparison with Pingfeng A. Pingfengyouxiangzhan was resistant to rice blast at moderate level and meet the 2nd class standard of fine quality issued by Ministry of Agriculture of China.【Conclusion】xa5 gene with resistance to bacterial blight and bacterial leaf streak of rice has partial dominant effect, which can be used for breeding improvement of hybrid rice; It is helpful to enrich and broaden the genetic basis of rice breeding by cultivating the superior hybrid combinations of rice with moderate resistance to bacterial blight and stripe disease with wild rice blood. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to clarify the relationship between rice flavor quality and nitrogen nutrient absorption and utilization, the genotypes of high nitrogen efficient and good taste value rice were selected.【Method】The excellent japonica rice varieties（strains） cultivated along the yellow area were used as the test materials, and the influence of nitrogen on different rice genotype rice quality and nitrogen absorption and utilization was studied by setting different nitrogen fertilizer levels. 【Result】The taste value of different genotypes rice showed high difference, which decreased with nitrogen application increasing. The taste value of no nitrogen fertilizer was the highest and up to 83.9. Protein and straight starches increased with nitrogen application increasing. The linear analysis showed a significant open downward parabolic relationship and was performed with the nitrogen application quantity and the taste value(r=0.998**). The milled rice rate and the whole head rice rate increased with the nitrogen amount increasing, and the chalky grain rate and the chalkiness decreased with the nitrogen amount increasing. The nitrogen use efficiency, nitrogen grain production efficiency and nitrogen harvest index differed greatly between genotypes. The excellent and high-efficient nitrogen rice genotypes represented by by xindao 89 and xinkedao 31 were generally manifested with good appearance quality and relative high nitrogen grain production efficiency, up to 56.44 kg/kg. The related analysis showed that the nitrogen grain production efficiency was significantly positively with the rice taste value and significantly negatively with the protein content. The nitrogen use efficiency was significantly negatively with the taste value, negatively with the chalky grain rice rate and chalkiness, and positively with the milled rice rate and the whole head rice rate. It showed that the taste quality of rice improved and the appearance quality decreased under the level of no or less nitrogen fertilizer.【Conclusion】The nitrogen grain production efficiency can be used as an important evaluation index of excellent quality and high nitrogen efficient rice breeding. Improving the nitrogen use efficiency may be more conducive to improving rice processing, appearance quality and rice yield level. Good quality with high nitrogen efficiency（high nitrogen grain production efficiency） and high yield with high nitrogen efficiency（high nitrogen use efficiency） can be used as important evaluation standards for excellent food taste rice breeding and high yield rice breeding, respectively. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to clarify the distribution of rice blast resistance genes Pib, Pi9, Pi2, Pi54 and Pish in Japonica rice varieties (lines) and the resistance levels of different genotype to rice blast. [Method] A total of 93 rice materials were assessed by artificial inoculation and screening of molecular markers tightly linked to 5 major resistance genes. [Result] Three, two and one resistance genes were found in 19 (20. 4%), 25 (26. 9%) and 28 (30. 1%) materials, respectively, and five resistance genes corresponding to markers were found in all varieties (lines). There were 49 (52. 7%), 16 (17. 2%), 8 (8. 6%), 31 (33. 3%) and 31 varieties (lines) (33. 3%) containing rice blast resistance gene Pib, Pi9, Pi2, Pi54 and Pish in 93 varieties (lines), and the genetic frequency of Pib was the highest within this collection. A total of six genotypes and gene combinations (Pi9, Pi54, Pib + Pi9, Pib + Pi2, Pib + Pish and Pi9 + Pi54) are applicable in the rice-breeding, due to the resistance to rice blast but with low distribution in the tested varieties (lines). [Conclution] The study provided a scientific basis for breeding rice cultivars with rice blast-resistance. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimedto analyze the change of resistance of different resistance genes and gene combinations to panicle neck pest. 【Method】The genotype of 80 resource materials screened for annual resistance were detected with the functional or closely linked markers of rice blast resistance genes Pi-ta, Pi-b, Pigm and Pi54 in rice, combined with the identification of rice panicle blast resistance for two consecutive years. 【Result】The results showed that among 80 experimental materials, 4 cultivars only carried Pi-b, 5 cultivars only carried Pi54, 8 cultivars carried Pi-b+Pi54, and 10 cultivars carried Pi-b+Pi54+Pigm. Rice cultivars carrying Pi-b+Pi54+Pigm gene combination did not show high susceptibility in two continuous years’ artificial identification. Two years’ correlation analysis between resistant genes and neck blast resistance showed that the disease resistance of single gene was gradually weakened and even lost. 【Conclusion】It was an effective way to enhance the disease resistance of rice to polymerized genes with broad antimicrobial spectrum and strong resistance in rice breeding. [ABSTRACT FROM AUTHOR]