Biomedical Engineering Reference
In-Depth Information
[
27
]. Hybrids between Minay and abaca, with the latter serving as male parent, have
been produced. The hybrids resemble the Minay parent more than the abaca parent
[
18
]. Artificial hybridization proceeds more effectively when the abaca is the male
parent.
A triploid and three tetraploid
Musa
which produce low-quality fiber have been
studied and used in breeding [
27
-
29
]. Two abaca varieties, Inosa and Laguis, were
found with chromosome numbers varying from 2
n
¼
17 to 2
n
¼
23 and 2
n
¼
16 to
2
n
24, respectively [
30
].
As of 1928, there were already hybrids developed for the varietal improvement
of abaca (Table
12.3
). Crosses between Libuton and Itom, as well as Canorajan and
Lagurhuan, were developed [
31
]. There were 54 different crosses developed from
1928 to 1931; however, only 29 crosses were successfully planted, 19 in
Guinobatan Abaca Experiment Station and 10 in Silang, Cavite [
5
]. Screening for
disease resistance was also carried out in 39 clones. Heterosis was observed in the
F
1
abaca hybrids. The F
1
hybrids produced greater number of abaca suckers than
either parent. Crosses with Maguindanao were better adapted to different conditions
and possess stronger root system.
In 1974, abaca hybrids developed in 1939 were field tested, and they were named
after the name of the parental line. The hybrid from Linawaan
¼
Laylay was named
as Linlay, Linawaan
Inosa as Linino
[
32
]. Oyardo [
33
] also field tested and named some abaca hybrids such as from
Itom
Libutanay as Linlib, and Linawaan
Lausigon as Itolaus, Itom
Maguindanao as Itomag, and Lausigon
Maguindanao as Lausimag.
The abaca varietal improvement program in UPLB was started in the early 1950s
initiated by the university's College of Agriculture (UPCA) and the Bureau of Plant
Industry (BPI) with emphasis on varietal collection, classification, evaluation,
establishment of disease observation nurseries, clonal selection, and intra- and
interspecific hybridization. The cooperative work was centered on the development
of resistant abaca varieties, and the most notable achievement was the identification
of
Pacol
as a source of resistance. Hybridization was done between
Pacol
and
abaca; however, the project was terminated in the 1960s. The abaca collection was
then maintained by the UPLB Forestry Abaca Gene Bank and was turned over to
the UPLB Experiment Station in 1981.
Diaz [
34
] generated F
1
hybrids of Mininonga crossed with six varieties of abaca
and screened for bunchy top resistance. Of the different crosses developed, only the
following crosses produced F
1
seedlings: Malaniceron
Mininonga, Mininonga
Itolaus 39, Mininonga
Layahon, Mininonga
Putumag 22, Mininonga
Tinawagan Puti, and Sogmad Pula
Mininonga. The reaction of these F
1
hybrids
to abaca bunchy top varied; Malaniceron
Mininonga, Mininonga
Itolaus
39, and Mininonga
Layahon have resistance to bunchy top virus, while Sogmad
Pula
Mininonga hybrids has moderate resistance.
In 1999, six abaca hybrid genetic stocks (Itolaus 39
Magsarapong 2, Itolaus
39
Magsarapong 3, Itolaus 39
Magsarapong 4, Itolaus 39
Magsarapong
7, Itolaus 39
Ilolaus 39) were identified by the
Institute of Plant Breeding. These genetic stocks were developed by conventional
Magsarapong 8, and Tetraploid
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