ITEMS FROM THE PEOPLES REPUBLIC OF CHINA
HENAN ACADEMY OF AGRICULTURAL SCIENCES
Wheat Institute, Zhengzhou, Henan, PRC 450002.
Wheat breeding.
Z.J. Lin, Q.R. Lai, R.Z. Fu, G.C. Cao, J.S. Ma, Y.R. Sun, Z.K. Chen, and M.L. Yi.
1994-95 season.
A warm winter and a spring frost resulted in damage to some spring
varieties. Precipitation was less than normal for the year, severely
reducing the yield in the rain-fed region. However, sunshine and
temperature were favorable during the grain-filling period. Kernel
weight was higher than normal this year, and yield in some of
the irrigated regions even increased. Therefore, the total yield
was reduced by only 5 % compared to last year.
Recurrent selection. Continued
recurrent selection still provides sources of disease resistance.
From the recurrent selection population, some lines were selected
that possess higher yield potential, along with high resistance
to the powdery mildew fungus. Two of the lines also possess good
quality for biscuit manufacture. Thus, recurrent selection can
be used for improving different characters simultaneously.
Gene transformation. Immature
embryos of a wheat cultivar were bombarded in the presence of
plasmid TABNBAR 55, which contained the artificial sterile gene
barnase and selectable marker gene bar. Resistant
calli were selected on Basta media. Some green plants were regenerated
from resistant calli, whereas no green plants were regenerated
from control calli. Southern blotting of DNA from the green plants
confirmed stable integration of both the barnase and bar
genes into nuclear DNA.
NANJING AGRICULTURAL UNIVERSITY
Wheat Breeding Institute, Nanjing 210095, China.
Guo-Liang Jiang, Shi-Rong Yu, Xi-Zhong Wei, You-Jia Shen, Yong Xu, Zhao-Xia Chen, and Shi-Jia Liu.
An original base population with wide genetic variability
was developed by multiple-parent crossing, intermating, and recrossing
using the dominant male-sterile gene ms2(Ta1). Phenotypic
recurrent selection then was conducted for male-sterile plants
in order to improve the population and develop a gene pool with
increased resistance to scab in wheat. The RC0-RC2 and
RC1-RC5 generations from the resistance resource pool were
evaluated for resistance, and the effect of population improvement
was analyzed in Nanjing under soil-surface inoculation with F.
graminearum-diseased seeds and single-floret inoculation
with G. zeae, respectively.
The experimental results of the soil-surface inoculation
indicated that the numbers or percentages of diseased spikelets
and seeds per spike of the male-fertile plants decreased significantly
and the comprehensive resistance of the population to scab obviously
was increased. The percentages of uninfected seeds per spike in
generations RC0, RC1, and RC2 were 49.2 %, 65.5 %, and 70.7 %,
respectively. The frequencies of plants with lower than 30 % diseased
spikelets and seed set in the population increased by 40 % and
36 %, respectively, through two cycles of selection. Under single-floret
inoculation, the results further demonstrated that the resistance
to fungal spread could be improved significantly through phenotypic
recurrent selection.
The opportunity of obtaining superior resistant plants
from the population would be enhanced gradually with the development
of the gene pool. On average, in each cycle from RC1 to RC5, the
population mean of diseased spikelets of inoculated spikes was
reduced by 8.6 %, and the frequency of resistant plants with fewer
than four diseased spikelets per inoculated spike increased by
4.2 %. The frequency of susceptible plants with more than 10 diseased
spikelets in the inoculated spikes decreased by 9.2 % after four
cycles of selection. The genetic variance for resistance was reduced
remarkably, but no significant decrease in the genetic coefficient
of variation was found during the first four cycles of selection.
Screening white wheat germplasm for preharvest sprouting tolerance.
Sprouting damage during harvest time is a severe
problem for wheat production in the mid-lower Yangtze River Valley
in China. Simple, convenient, and reliable evaluation methods
and utilization of resistance germplasm should be the basis for
breeding white-seeded cultivars with preharvest sprouting tolerance.
More than 60 white wheat cultivars from different regions of China
and 41 advanced lines from our breeding program were evaluated
for seed germinability in ears during 1991-95. Germination
tests were made by wrapping water-soaked, intact spikes in plastic
packets. To preserve a high humidity and facilitate sprouting
under room conditions, they were stacked upright in a plastic
rectangular container. The averages of sprouting percentage of
all materials tested in 1991, 1992, 1993, 1994, and 1995 were
21.98 %, 16.93 %, 11.86 %, 19.30 %, and 21.25 %, respectively.
The ranges of variation were 0.53-76.75 %, 0-77.58
%, 0.12-56.31 %, 1.93-64.58 %, and 0.01-94.82
%, respectively. The sprouting percentage for the seven local
cultivars or landraces and 11 improved cultivars or breeding lines
was less than 15 % or the `mean minus the standard deviation'
of all materials each year. These materials would be useful to
breeding for preharvest sprouting resistance in white wheat.
A preliminary study on inheritance of sprouting tolerance in white wheat.
Ten resistant, white-grained cultivars/lines used
as paternal parents were crossed with five susceptible, white-grained
cultivars. Twenty-nine F1 and 20 F2 combinations and their parents
were planted in 1993-94, and germination percent in ears
was determined. The comparison between the F1 performance of the
reciprocal crosses did not show a maternal effect in the inheritance
of sprouting resistance. For all of the F1 and F2 generations,
the mean sprouting percent was between the two parents, and that
of F1 generation was lower than the mid-parent value in most combinations.
Thus, partial dominant effects existed in the resistance inheritance.
A nonsignificant correlation occurred between F1 and F2 (r = 0.418).
Compared with the F1, the average sprouting percentage obviously
increased and about reached the mid-parent values in most F2 generations,
but was reduced in three combinations. The frequency distributions
of the sprouting percentage in the F2 generations appeared continuous
and resembled a deflective or normal distribution in shape. Resistance
to sprouting in white wheat might be inherited as a quantitative
trait with complex performance. The resistance of the hybrids
could be enhanced by backcrossing with the resistant parent.
Rational evaluation of cultivars in wheat cultivar registration.
A set of wheat-cultivar regional test data from the
Jiangsu and Shandong Provinces was used as an example to demonstrate
the analysis methods. The following problems with rational evaluation
of cultivars in registration are discussed.
1. The precision of cultivar regional tests. We proposed that the scale might be measured by
2. The statistical model in a complex analysis of variance. The complex variance analysis for environments and cultivars in regional tests might be a better model.
3. Stability and adaptability parameters. The bi can be the expressed adaptability parameter, and ai can be a stability parameter.
4. Rational evaluation of cultivars.
Grouping the estimation of parameter analysis was suggested.
Development of cultivars and germplasm.
`Changjiang 8809'
is a scab-resistant cultivar developed through recurrent selection
integrated with conventional breeding methods using the dominant
male-sterile gene Ta1(ms2). This cultivar outyielded `Yangmai
5' by 4.92 % in regional experiments in the Anhui Province
and decreased in production compared with `Yang 158'
in both the Anhui and Jiangsu Provincial tests during 1994-95.
New strains and germplasm with high-yielding capacity,
such as Changjiang 9045, 9046, 9206, 9207, 9401, 9403, 9404, and
9405, were bred during the development of a scab-resistant gene
pool. Under usual conditions, their grain yield was between 5.25-6.00
t/ha, and they outyielded the checks Yangmai 5 and Yang 158 by
10-15 %. The cultivars W14 and Changjiang 9306, 9307, and
9311 also were demonstrated to possess higher resistance to scab
spread than the resistant cultivar Sumai 3 in JAAS and NAU.
Publications.
Jiang G-L, Wu Z-S, Chen Z-X, Yu S-R, and Wu J-M.
1995. Effectiveness of population through recurrent selection
for scab resistance in wheat using dominant male-sterile gene
ms2. Sci in China (Series B) 38(11):1361-1369
(in English); 25(6):610-615 (in Chinese).
Jiang G-L, Chen Z-X, and Wu Z-S. 1996. Screening
white wheat germplasm for pre-harvest sprouting tolerance. Seventh
International Symposium on Pre-Harvest Sprouting in Cereals, Japan.
(In press).
Xiao S-H, Wu Z-S, Shen Y-J, Jiang G-L, Dai D-Q, Jiang
H-R, Qin D-H, and Jiang D-Y. 1995. A study on exploring resistant
germplasms to pre-harvest sprouting from local varieties of wheat
(Triticum aestivum L.) in Yangtze Valley. Sci Agric Sinica
28(1):56-60.
Yu S-R, Lu Z-M, Zhou Y-Z, and Zhu L-X. 1995. Rational
evaluation of cultivars in wheat cultivar registration. Sci Agric
Sinica 28(3):87-93.
BC INSTITUTE FOR BREEDING AND PRODUCTION OF FIELD CROPS
Marulicev trg 5.I, 10000 Zagreb, Croatia.
The breeding of hard winter wheat (T. durum Desf.) in Croatia.
S. Tomasovic and P. Javor.
Because of the fact that a large part of the Republic
of Croatia has a Mediterranean climate very favorable for growing
durum wheat, we established a separate breeding program for these
wheats. More than 2,500 genotypes have been collected since 1985,
some of which are suitable for use in the breeding program. The
most important properties for our agroecological conditions are:
winterhardiness, spike fertility, low stature, culm strength,
size and position of leaves, and length of the vegetative period.
In choosing parents, special attention is given to
gentoypes with high resistance to fungal diseases, especially
Fusarium and Septoria spp. After crossing in breeding
generations, we use the `pedigree' method with modified
discontinual individual selection.
The best durum lines (Tables 1 and 2, page 73) were submitted for registration to the National Committee of the Republic of Croatia, including the lines `BcTD 3201/92', which is in the final year of testing, and BcTD 3200/92.
Insert Tables 1 and 2 from Croatia contribution.