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Rice Genomics and Genetics 2012, Vol.3, No.2, 8
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12
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was arranged in hot dry season (7
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8 months) prior to
transplanting. It began to drain water off prior to
weeding and fertilizing after transplanted seedlings
reviving until the stages of heading and maturity. Both
of drought-resistant varieties of “Brazilian upland rice
and Jinggang upland rice No.1” and the recipient
parent "Ganxiang B" were employed as the controls,
of which began to be curling as criteria for selection,
seed rate and other traits.
Screening for tolerance to low nitrogen: Transplanting
24 individuals per lines followed line by line, fertilizer
of urea 75 kg per hectare was topdressed in the stage
of seedling reviving after transplanting, on any addi-
tional fertilizer applied. Growing traits were recorded
including plant biomass, tiller numbers, panicle length,
grain number etc. The receptor of Ganxiang B used as
control, the line that most of selection criteria was
better than that of the control lines was screening out
as low nitrogen-tolerant line.
Screening for rice blast resistance: All lines for blast
identifying were planted in the Fengtian village of
Kenzhi Station in Jingguangshang where was heavy
blast-prone area, where is a national station of southern
regions of rice and Jiangxi provincial station for rice
blast identification. Incidence of leaf blast and panicle
blast occurs severe every year. In Seeds sown in late
May, transplanting followed by lines, 15 individuals
per lines transplanted with in density of 16.5 cm×
13.2 cm. Using LijiangXintuanHeigu and recovering
line 752 were employed as references, the appropriate
urea was applied. leaf blast was investigated during
the vegetative growing stage and panicle blast were
investigated in the early ripening stage based on the
national standard GB/T 15970, grade 1~3 was classified
as leaf blast resistance, grade 4~9 was classified as a
susceptible to rice blast, incidence rate less than or
equal to 5% stands for resistance to panicle blast
while greater than 5% stands for susceptible to panicle
blast.
Screening for high-temperature tolerance: Transplanting
24 individuals per lines followed line by line, The
growing stages of booting, heading and filling were
matched in the hot season, labeling spike blooming in
hot temperature, after 20 days labeling the seed setting
rate was investigated, if the seed setting rate was
more than 70% that the line was considered as high
temperature tolerant line.
Screening for flooding resistance: Seeds mixed by
lines were sown in the deep bucket with soil placed
outdoors, growing to 1 leaves with new emerging
leaflet, seedlings were submerged, refreshing the water
(filling water instead of pouring water) in bucket
every three days to prevent possible toxic to seedling
due to fermentation happening, after 7 days later
draining water out, the alive seedlings were investigated
in additional 5 days later in the outdoor.
Screening for herbicide resistance: Seeds mixed by
lines were sown in the nursing field prior to soaking
and germinating. The seedling with 2 leaves was
uniform spraying herbicide glyphosate isopropylamine
salt (41%), and re-spraying three days later after first
spraying. Ganxiang B used as a control, the number of
alive seedlings were investigated after 10 days of
re-spraying.
Authors' contributions
Yeqing Xiao is the person who conducted experimental design
and performances and wrote the manuscript. Xiaoyan Wu,
Lanxiang Hu, Wenchang Wu, Shiyou Luo and Wei Deng
involved in doing research work. Dazhou Chen is principal
investigator who conceived the project and supervised the
experimental designing, data analyzing, and paper writing and
revising. All authors have read and agreed the final context of
manuscript.
Acknowledgments
This research was jointly funded by 948 project (2006
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G1) of
the Ministry of Agriculture, 863 project (Innovations of
drought-resistant germplasm of rice) and Project (51587
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13) of
the Bill & Melinda Gates Foundation. Authors thank the two
anonymous peer reviewers for their critical comments and
helpful revising. Thanks Dr. Xianhua Shen of our Institute for
his revising this English version.
Reference
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Xu J.L., Gao Y.M., Fu B.Y., and Li ZK., 2005, Identification and screening
of favorable genes from rice germplasm in backcross introgression
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