2.5 Analysis
The following method was adopted to select plants with improved economic and ecological
traits: firstly, calculate the ecological benefit index, then preliminary select the family whose value
of ecological benefit index is higher than the average, finally, decide the improved economic
ecotype plants by Fuzzy Option System combined factors of fruit yield of single plant, fruit
diameter, 100--fruit weight, and thorn number with ecological benefit index.
The term of ecological benefit index proposed by Professor Huang Quan from the Chinese
Academy of Forestry was adopted. Ecological benefit index is abbreviated as EB in the following
equation:
EB = V t [1-W+(s/a)] (1)
where
V = the average volume of plant crown, which is calculated as: V = 4/3
AB
2
(A: half of the
average height of plant, B: half of the average crown width of plant)
t = the density of leaves
W = the ratio of withered trees to the total
s = the number of suckering
a = the age of plant.
3.
Results and Analysis
3.1 Comparison and analysis of ecological benefit for each observed family
The main purpose of the selection is to choose the improved economic--ecotype of
seabuckthorn. The selected plants should be of high adaptability and ecological benefit (Zhang
1997). Those of poor growth and low ecological value should be discarded.
We applied the data obtained in 1998 from the F
1
-generation experimental plot to the above
formula and got the ecological benefit indexes as shown in Table 1.
Table 1 shows that the EBs of the F
1
plants originating from Zhengyuan of Gansu province
(GZ) and Huanglong of Shanxi province (SL) are much higher than the average. The main reason
is that the latitude of the above places is similar to that of the experiment plot. The EBs of MK and
HbF origins are lower than the average EB, which showed that seeds of these origins were not
suited to the environment of the experimental area. According to the results of the tested 57
families, the EBs of 14 families are higher than those of the control families. Based on the
ecological effects, the EBs of 23 families are higher than the average EB. Among them are 4 of
HbF, 6 of MK, 4 of SL and 4 of SH, and 9 of GZ, respectively.
Based on the EB evaluation of the selected 23 families, further evaluations were conducted.
The data are shown in Table 2.
3.2 Comprehensive evaluation of the tested families
The following criteria were used in the evaluation:
Ø
fruit diameter
Ø
100--fruit weight and fruit yield of single plant
Ø
number of thorns on 10cm long branch of 2-year-old plants
Ø
ecological benefit index.
Following the requirement of the Fuzzy Option System, firstly, the units of the original data
were adjusted according to the following formulas (thorn number was adjusted according to
Formula (2) and the other factors were adjusted according to Formula (3)):
Xij = Xij/Max xij
(2)
Xij= Mini xij/xij
(3)
