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Wheat Information Service
Number 84: 1-6 (1997)
Research article
Study on utilization of the dominant male sterile
triticale in breeding sterile triticale in breeding
Yuanshu Sun and Chongyi Wang
Institute of Crop Breeding and Cultivation, CAAS, Beijing 100081,
China
Summary
This paper describes the fertile segregating progenies derived
from crosses and back crosses between male sterile triticale lines
and hexaploid and octoploid triticale and the populations established
for rotational selection. Gene recombinations took place extensively
for breaking down adverse gene linkages and improvement of the
frequency of favorable genes, seed plumpness, and the synthesis of
good characters.
Key words: triticale, male-sterile line, rotational
selection
Introduction
Triticale, first grown in China in the 1970's, has shown
significant potential in disease resistance, stress tolerance,
nutritional quality and yield. However, it has not been used
extensively because of poor traits such as plant height, late
maturity, low seed test weight and low flour yield due to shrivelled
seed. Triticale was grown on approximately 0.4 million mu (one
hectare is equal to 15 mu) in the early 1980's in China. However, the
sown area later decreased because of the problems mentioned above.
Shrivelled seed and the adverse characters of triticale are
controlled by multiple factors and are linked with adverse genes;
thus the problems cannot be resolved with conventional breeding
methods (Wang and Sun 1986). We have done several thousands cross
combinations and long term selections without success. The dominant
male sterile materials are good tools for rotational selection of
triticale. They can be used in the short term for gene recombination
and breaking down of adverse gene linkage, but they can also improve
the frequency of good genes and the good traits of the dispersed
multiple genes can be combined (Liu and Deng 1986; Ji and Deng 1986;
Darvey 1986). Therefore, it is an effective method for improving the
plumpness of seed and adverse characters of triticale.
Materials and methods
The establishment of triticale male sterile lines
In 1982, crosses were made between male sterile Chinese Spring Ms2,
and the rye AR132. The Ms2 dominant male sterile gene was
transferred into octoploid triticale through hybrid' chromosome
doubling in the second year. Triticale sterile lines with different
characters ha been bred through crossing with hexaploid triticale
OH1, WOH45, WOH63 and octoploid triticale H1162, H2645, H8301 in
1983-1987.
Group combination
The triticale sterile lines were divided into groups according to
breeding objectives such as maturity period, plant height, grain
quality, and as food or feed. Ten to 15 lines were selected from each
group for inter crossing; a) semi-diallel crosses: fifteen lines for
each group and 105 single crosses. were made according to the formula
n(n-1)/2; b) random crosses: from 1988, sterile plants were
interplanted for natural random crosses. Thus the genes in the CO
population can be full: combined.
Rotational selection
According to the breeding objectives for each group, 200-500 sterile
and fertile plants were selected among CO population and sterile
plants were mixed and entered into the C1 (Fig.1).
The fertile plants whose main traits exceeded the average of the
population in female parent row were selected and mixed as male
plants of C1 after testing. Selection for C2 was carried out
according to the selective method for C1. Thus hybridization and
selection can be carried out Bonce at each cycle. Selection
concentrated on the female gamete of fertile plants. Selection aimed
to improve characters such as plant height, bushiness, winter
hardiness, disease resistance, date of heading, etc. It should be
carried out before anthesis in order to reduce the diffusing of
adverse genes among the population. The results of selection were: a)
comparison between each cycle, and b) comparison with conventional
selection. The distribution of seed plumpness and the important
traits of fertile plants were assessed after each cycle of
selection.
Seed plumpness is divided into five grades according to the degree of
endosperm development and pericarp smoothness; 1 grade: the endosperm
is full of seed coat and pericarp is the most smooth, 2 grade: the
pericarp is quite smooth, 3 grade: the endosperm is about 3/4 full of
seed coat, 4 grade: the endosperm is about 1/2 full of seed coat, and
5 grade includes others. Each plant may evaluate 2.5, 3.5, or 4.5
seed plumpness depending on percentage of different grade seeds.
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