(to
KOMUGI Home) (go
to WIS List) (go
to NO.76 Contents)
Wheat Information
Service
Number76:56-58 (1993)
Effects
of Aegilops crassa cytoplasm on agronomic characters of
F1 hybrids
K. Murai1*, H. Hirohara1 and K.
Tsunewaki2
1Takarazuka Research Center, Sumitomo Chemical Co.,
Takarazuka, Hyogo 665, Japan
2Laboratory of Genetics, Faculty of Agriculture, Kyoto
University, Sakyo-ku, Kyoto 606-01, Japan
We have demonstrated that the male sterility in the alloplasmic line
of Triticum aestivum cv. Norin 26 with Aegilops crassa
cytoplasm was induced by long-day treatments of 15 hours or longer
light period, and proposed a new system for hybrid seed production
using this conditional male sterility (Murai et al 1991). In contrast
to the system using T. timopheevi cytoplasm, the
present system requires only the male sterile and pollinator lines,
so that it is called "two-line system" for hybrid wheat production.
In this report, we examine the genetic effects of the Ae.
crassa cytoplasm on the F1 hybrids.
Materials and Methods
Five alloplasmic lines, Ae. crassa/11*Norin 26 (Tsunewaki
1980), Ae. crassa/6*Shirasagi-komugi, Ae.
crassa/6*Junrei-komugi, Ae. crassa/6*Fujimi-komugi and
Ae. crassa/5*Asakaze-komugi, and five cultivars, Norin 61,
Nichirin-komugi, Ushio-komugi, Sakigake-komugi, and Orofen, were used
as the male sterile and restorer lines, respectively. Twenty-three
F1 hybrids were produced by hand-pollination. They were
space-planted at the Kasai Experimental Farm of Sumitomo Chemical Co,
Hyogo, Japan, and compared their agronomic characters and heterosis
on grain weight/plant with the F1 hybrids having the
corresponding normal (wheat) cytoplasm.
Results and Discussion
Average performances on agronomic characters of the 23 F1
hybrids with the Ae. crassa cytoplasm and with the
normal (wheat) cytoplasm are shown in Table1.
Two F1 hybrids, Junrei-komugi x Sakigake-komugi and
Fujimi-komugi x Nichirin-komugi, were not available for this
investigation because of their low germinability and a small number
of seeds obtained, respectively. The average of five (or four)
pollinators is given in the table. The analyses of variance revealed
that the effects of the Ae. crassa cytoplasm were significant
on five characters, grain number/ear, grain weight/ plant, 1000-grain
weight, selfed and open-pollinated seed fertilities (Table
2). Fujigaki and
Tsunewaki (1976) reported that the T. timopheevi
cytoplasm hastened heading date and increased plant height
and ear number/plant in Japanese cultivars. However, our results
indicated that the effects of the Ae. crassa cytoplasm were
not significant on these characters. The over-all averages of both
the selfed and open-pollinated seed fertilities of the F1
hybrids with the Ae. crassa cytoplasm were11% lower than
those of the F1's with the wheat cytoplasm. The decreases
in grain numberlear and grain weight/plant of the F1
hybrids with the Ae. crassa cytoplasm were associated
with their lower fertility than that of the F1's with the
wheat cytoplasm. A significant increase in 1000-grain weight of the
F1 hybrids with the Ae. crassa cytoplasm is
probably due to the compensatory effect of the decreased seed
fertility. No significant effect of the cytoplasm was detected on
test weight, indicating that the grains of the F1 hybrids
with the Ae. crassa cytoplasm were not shriveled. In spite of
the decreased fertility (80% fertility), the F1 hybrids
with the Ae. crassa cytoplasm showed, on the average, 20% and
14% heterosis on grain weight/plant over the check cultivar (Norin
61) and the average (mid-parent) of the female and male parents with
the wheat cytoplasm, respectively. Fig.1
shows ears and grains of the F1 hybrids between
Junrei-komugi x Nichirin-komugi and Norin 26 x Nichirin-komugi, which
showed the highest standard and mid-parent heterosis,
respectively.
References
Fujigaki J and Tsunewaki K (1976) Basic studies on hybrid wheat
breeding. VII. Characteristics of the male sterile lines of common
wheat cultivars. Jpn J Breed 26: 179-186.
Murai K, Hirohara H and Tsunewaki K (1991) A new system for hybrid
wheat production using Aegilops crassa cytoplasm. Wheat Inf
Serv 72: 91-94.
Tsunewaki K (1980) Genetic diversity of the cytoplasm in
Triticum and Aegilops. Japan Society for the Promotion
of Science, Tokyo.
*Present address: Research
Institute of Agricultural Resources, Ishikawa Agricultural College,
Nonoichi-machi, Ishikawa 921,Japan
(go
to KOMUGI Home) (go
to WIS List) (go
to NO.76 Contents)