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Legume Genomics and Genetics 2012, Vol.3, No.3, 14
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would provide an important study direction and
material for further research in PD relative genes and
their regulatory network.
3 Materials and Methods
3.1 Materials used in this research
The soybean female parent was
Glycine max
Merr.,
The CV Jinbean 23 which does not shatter easily after
maturation; the male parent was pod shattering
susceptible cultivar,
Glycine max
Merr. CV. ZDD2315,
which shatters easily after maturation. The recombinant
inbred lines (JINF population) were constructed from
the female and male parents. All of these materials were
provided by Xueyi Liu from Industrial Crop Research
Institute, Shanxi Academy of Agriculture Sciences.
3.2 Genetic map of soybean and QTL analysis
Yusong Wan et al (2005) used the JINF population as
materials, and integrated a soybean genetic linkage
map which has 227 SSR markers. Based on the SSR
markers in this map and the markers in soybean public
map, Pengtao Gong et al (2006) re-integrated a new
genetic linkage map. In this research, 240 SSR
markers from the soybean molecular genetic map
constructed by Pengtao Gong (2006) were used to
identify the QTLs for the related traits.
Open the "Frequencies" dialog box in "Descriptive
Statistics" under "Analyze" with SPSS 16.0, select
"Histogram" and "With normal curve", and make the
column charts for the three related traits. Next,
open=the "Bivariate" in "Correlate" under "Analyze"
with SPSS 16.0, select the "Means and standard
deviations" and "Excludes cases pairwise" in
"Options" box, set the "Correlation Coeffecients" as
"Pearson", select "Two-tailed" in "Test of Significance",
and analyze the correlations of the three related traits.
Import the data to the WinQTLCat 2.5 software
(http://statgen.ncsu.edu/qtlcart/WQTLCart.htm), set
the "Walk speed" as 2, and "By Manual Input" as 11.5,
the rest boxes as default values to map the QTLs for
the three related traits by CIM.
3.3 Soybean planted in the field
The materials for the research were dried in the sun
for one day. The seeds were planted at the square
pots (20 cm×20 cm) of Hainan Institute of Tropical
Agricultural Resources (HITAR), on August 5
th
, 2011.
Each pot has 4 kg clay (The clay also needs to be
dried in the sun for one day and mixed with fertilizer).
Three pots for each parent, and the one pot for each of
the 112 strains were grown. 5~6 seeds were planted in
each pot, and final singling was performed when
seedlings reach V
4
stage. Three strains were kept in
each pot. During seedling growth, watering and
weeding of the plants were performed periodically,
and the data record and harvest were completed at
relevant growing stages.
3.4 Phenotype dermination
3.4.1 Phenotype assessment of PD
The pods were collected (10~20 pods from each plant)
when the soybean was grown to R
8
stage (95% of the
pods have reached their mature, brown or tan color),
and all the pods were dried in room for 15 days.
The degree of PDH was evaluated by monitoring the
percentage of the dehiscent pods after heat treatment
at 80
℃
for 5 hours (Tukamuhabwa et al., 2002). In
the process of heat treatment, in order to prevent the
pods burst affect the outcome statistics, pods were put
into a flask first. The percentage of shattering pods
was then recorded, and average was obtained from the
3 replicates of each strain. The cylindrical map was
created with SPSS 16.0 (Figure 4).
3.4.2 Phenotype assessment of RTW
Pods were collected (10 pods per plant) when the
plant was grown to R7 stage (when one normal pod at
any node on the main stem has reached its mature
brown or tan pod color). Next, we measured the total
width and total thickness of these pods. Measurement
of the total width of pods was based on the method of
Liu et al (2003), which measures the width by lining
up 10 pods side by side according to the direction of
its width, measuring the total width and calculating
the average. Measurement of the total thickness of
pods was modeled after the above method. A simple
device was made by the author, which stacked the
pods in accordance with the direction of its thickness.
We measured the total thickness, and calculated the
average from the total. Then, we calculated the ratio
of total thickness to width, and averaged every three
repeats. The frequency distribution was obtained with