Search

[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] This paper aimed to overcome the easy breakdown of conventional disease resistant plants. [ Method] A new kind of transgenic rice plant5 was generated based on Host Induced Gene Silencing ( HIGS) technology. [Results] SEC11, a key subunit of signal peptide complex in Magnaporthe oryzae, was selected for generating the HIGS expression vector by gateway technology. HIGS vector was transferred into the Japonica rice cultivar Nipponbare by agrobacterium mediated transformation to obtain transgenic rice plants. The spray assay with conidia of rice blast indicated that the HIGS transgenic rice plants were improved in rice blast resistance. [Conclusion] This study lays the foundation for molecular breading of rice blast resistant varieties with HIGS technology. [ABSTRACT FROM AUTHOR]

[Objective] The purpose of this paper was to clarify the effect of diversity mixed interplanting mode on rice photosynthesis, and provide a favorable basis for the further application of diversity mixed interplanting in the field. [Method] The rice varieties Gangyou 157 (main planted variety) and Huangkenuo (interplanted variety) were selected, and their relative chlorophyll content SPAD values and photosynthesis were measured under the mixed interplanting and mono-planting modes, and the occurrence and damage of rice blast and the agronomic characteristics of rice were investigated. [Result] When Gangyou 157 in the interplanting mode, the SPAD value of the inner row was significantly higher than that of the outer row and mono-planting treatments.There was no significant difference in the SPAD value of Huangkenuo under the two planting modes.The net photosynthetic rate of Gangyou 157 in the interplanting mode was significantly lower than that of the mono-planting treatment (decrease by 14.36%), and there was no significant difference when compared with the outer row. The transpiration rate, stomatal conductance and intercellular CO2 concentration were significant differences in all treatments. The net photosynthetic rate, transpiration rate, stomatal conductance and intercellular CO2 concentration of Huangkenuo were not significantly different under the interplanting and mono-planting modes.Gangyou 157 and Huangkenuo had no significant difference in water use efficiency under interplanting and mono-planting modes. The rice blast disease index of Huangkenuo under the interplanting mode（2.79 ± 0.86） was significantly lower than that of the mono-planting（43.65 ± 6.11）,and its plant height under the interplanting mode（138.93±2.91）cm was significantly lower than that of the mono-planting（152.07 ± 2.27）cm, and the number of tillers of Huangkenuo under the mono-planting mode（9.75 ± 0.59） was significantly higher than that of the interplanting（7.04 ± 0.73）.There was no significant difference in disease index, plant height and tiller number of Gangyou 157 under the two planting modes. The yield per hectare of Huangkenuo under the diversity mixed-interplanting mode(6.23 t/hm² ) was significantly higher than that of the mono-planting model（4.50 t/hm²; the yield per hectare of Gangyou 157 under two planting modes was no significant difference. [Conclusion] Under the diversity mixed interplanting mode, the chlorophyll content of the main cultivars increased significantly, the photosynthetic rate decreased significantly, and other photosynthetic characteristics were no significant changes; the performance of the interplanted cultivars was not significantly different from that in the mono-planting mode. At the same time, the incidence of diseases of interplanted varieties was significantly reduced, without affecting the main varieties. [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]

Pita is a broad-spectrum resistance gene for rice blast and has been applied in different rice resistance breeding programs. In order to improve the efficiency for Pita selection based on molecular marker-assistant selection (MAS)，a gene-specific dCAPs marker，Pita918, targeted on single nucleotide polymorphism that result in single amino acid changed between resistant and susceptible allele of Pita on 918th aa has been developed in this paper. The result showed that Pita specific DNA marker Pita918 can distinguish Pita from other R genes and susceptible allele gene clearly，providing breeders an efficient and accurate marker for Pita selection. Additionally，Pita918 has been used for genotype characterization among 13 resistant rice landraces collected from south and southwest of China，the result showed that those landraces do not harboring Pita for their rice blast resistance，suggesting that Pita918 is a valuable DNA marker for genotype identification in rice germplasm，which will give breeders abundant genetic information in new resistance genes discovery [ABSTRACT FROM AUTHOR]