HENAN ACADEMY OF AGRICULTURAL SCIENCES
Wheat Institute, Zhengzhou, Peoples Republic of China.
Zuoji Lin, Shenhui Jie, Jiachang Zhang, and Zhengchin Wu.
The 199798 season.
The past season was a contrast to previous seasons in the Henan province. Although the winter weather was normal, precipitation in late spring was higher amd sheath rot (Rhizoctonia cerealis) was severe at most sites. Sunny days were scarce during grain filling, and grain weight decreased significantly. Some cultivars were nearly 20 % lower compared to a normal year. The total yield was more than 10 % lower than in 1996-97.
Space mutation breeding.
Favorable mutation material was selected from 3,200 Sp2 head lines and planted in four sites. Seventy-five lines were selected, favorable for mutations for higher yield, higher grain weight, and greater resistance to sheath rot.
New variety registered.
A new variety selected from a recurrent selection group was
registered as Yu-Mai 50. Yu-Mai 50 is resistant to powdery
mildew and has a higher yield potential than the check cultivar
Yu-Mai 18. Yu-Mai 50 is an SWSW, with good quality suitable for
sponge cakes and biscuits.
NANJING AGRICULTURAL UNIVERSITY
Wheat Research Laboratory, Weigang 1, Nanjing 210095, P.R. China.
Guo-Liang Jiang, Shi-Rong Yu, Xi-Zhong Wei, You-Jia Shen, Yong Xu, Zhao-Xia Chen, and Shi-JIa Liu.
Combining ability analysis of scab resistance for F1 and F2 in a '4 x 5' factorial cross of common wheat.
Nine genotypes with different levels of resistance to scab and genetic backgrounds were crossed in a '4 x 5' factorial cross to make effective use of excellent parents. A field trial including parents, F1s, and F2s was conducted in a randomized block design, replicated three times, at Nanjing. The number of diseased spikelets was observed to assess the fungal-spread resistance by single-floret inoculation with F. graminearum. Average numbers of diseased spikelets were less in the F1 and F2 than in the midparent for most combinations, indicating dominance effects of the resistance genes. The parental versus F1 effects and average degree of dominance showed that the midparent heterosis in the F1 was mainly attributed to overdominance. Effects of general and specific combining ability were significant for both the F1 and F2. For inheritance of resistance, the additive effects of resistance genes in the F2 played a more important role than those in the F1. Hence, parent selection in breeding pure lines should be based mainly on combining ability analysis for the F2 rather than for the F1. The effects of resistance levels of parents and their interaction on the performance of offspring should be considered. We suggest that two new resistant resources should be used in a breeding program.
Studies on preharvest sprouting and relative traits in red and white wheat.
Seven pairs of red- and white-grained lines of common wheat, each pair having similar genetic derivations or backgrounds, were used as experimental materials. Sprouting percentage in the spike (SPS) and germination percentage of hand-threshed grain (GPG) were determined before harvest, and seed dormancy, a-amylase activity, falling number, water uptake rate, and inhibition of seed germination by glume-extracting solution were measured after harvest. Significant varietal differences in SPS, GPG, seed dormancy, and a-amylase activity were observed. Compared with the corresponding red-grained lines, white-grained lines had higher SPS, GPG, and a-amylase activity; weaker dormancy; and a smaller falling number. In most cases, the range of variation for SPS and GPG was larger in the white lines than in the red lines. Pairwise comparisons showed that the differences between red and white lines were significant at the 0.01 level for SPS, GPG, seed dormancy, and a-amylase activity and significant at the 0.05 level for falling number. Highly significant correlations existed between SPS and GPG, seed dormancy, a-amylase activity, and falling number. However, the water uptake rate and inhibition of on seed germination by glume-extracting solution did not display obvious differences between the red and white lines. Correlations between SPS or GPG and water uptake rate and inhibition by glume-extracting solution were not significant. We concluded that seed color, dormancy, a-amylase activity, and falling number were closely related to sprouting resistance in wheat.
Personnel.
In March 1998, Dr. Guo-Liang Jiang, by invitation from Prof. K. Noda of Okayama University, made a 1-week visit to Japan. He visited the research Institute for Bioresources, Okayama University, Kurashiki, Okayama; the Shikoku Agricultural Experimental Station, Shikoku; and the Kitami Agricultural Experiment Station, Hokkaido, and made academic exchanges of research on scab and preharvest sprouting in wheat with Japanese colleagues. Mr. Ken Tanifuji, a wheat breeder at Kitami Agricultural Experiment Station, made a short visit to our laboratory in July. Mr. Guofeng Lu, from the Ningxia Academy of Agricultural Sciences and Mr. Tianrong Huang, from the Xinjiang Academy of Agricultural Sciences, came to our laboratory to study for their Master's degrees.
Publications.
Jiang GL. 1998. Combining ability analysis of scab resistance for F1 and F2 in 4x5 factorial cross of common wheat. Wheat Inf Serv 87:31-38.
Jiang GL and Chen ZX. 1998. Analysis of combining ability for preharvest sprouting tolerance in white-grained wheat germplasm resources. Acta Agron Sinica 24(4):491-496.
Jiang GL, Chen ZX, liu SJ, and Xiao SH. 1998. Pre-harvest sprouting in white wheats and its resistant characteristics of cultivars. Acta Agron Sinica 24(6):793-798.