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Plant Gene and Trait 2012, Vol.3, No.4, 18
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based on the specific primers P1 and P2, and the size
was about 750 bp in length (Figure 1). The PCR
product was separated on 1.2% agarose gels for
recovery, and then was cloned into PMD 19
-
T vector
(TaKaRa Biotech, Dalian, China). The result of
digestion and recycling showed that the size was same
to the target fragment, which indicated that the
fragments were transformed into the plasmids
successfully (Figure 2). And the recombinant plasmid
was sequenced by Sangon Biotech (Shanghai) Co.,
Ltd. The result showed that the length of the fragment
was 762 bp, named as SCAR
-
762 (Figure 3).
1.2 The heredity rule of SCAR molecular marker
related to early-bearing trait in maternal parents
and F
1
generations
The DNA of four parents and a control were amplified
based on primers P1 and P2 (Figure 4). The result
showed that SCAR molecular marker could be
obtained in early-bearing parents, but not in the
control of late-bearing, which indicated that the SCAR
molecular marker was related to early-bearing trait in
walnut. We also found that there was no difference
among the early-bearing parents.
Figure 1 The result of SCAR amplifications
Note: 1~2: The DNA of early-bearing species; CK: The control;
M: DNAMarker D
Figure 2 The result of plasmid PCR
Note: 1~3: Plasmid; M: DNAMarker D
Figure 3 Sequence of SCAR marker SCAR-762 linked to walnut early-bearing gene
Note: The primers were underlined
The F
1
generations of the five parents were amplified
based on the specific primers P1 and P2 (Figure 5;
Figure 6). The results showed that 39 plants of 41 in
Lun 1 had the SCAR molecular marker, 42 plants of
43 in Lun 2 had the SCAR molecular marker, 27
plants of 28 in Lun 3 had the SCAR molecular marker,
27 plants of 29 in Lun 4 had SCAR molecular marker,
and 43 plants of 44 in Lun 5 had SCAR molecular
marker, respectively. The percentage of this marker in
the F
1
generations was 92.68%, 97.92% 96.43%, 93.10%
and 97.73%, respectively (Table 1). The results indicated
that early-bearing was an high heredity trait, which
displayed the same result as Yang et al (2007).
2 Discussion
The stage of flowering was an important turning phase
during the development process of fruit tree, the time
of flowering would affect the fruit directly, To
understand the molecular mechanisms of flowering,
genetic and molecular biological approaches have
been used to isolate the key genes that regulated
flower development, such as,
Carya cathayensis
(Wang
et al., 2006; 2008),
Cictus
(Liu et al., 2001),
Prunus
(An et al., 2008) and
Malus domestica
(Cao et al.,