Climate Change and Dryland Agricultural Ecosystem Management

Competitive ability and yield stability in winter wheat old and
modern cultivars
Yan Fang1,2,3, Lin Liu1,2,3, Bingcheng Xu1,2 and FengMin Li1,2,*
1State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water
Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling Shaanxi 712100, China.
2MOE Key Laboratory of Arid and Grassland Ecology, Lanzhou University, Lanzhou 730000, China.
3Graduate School of Chinese Academy of Sciences, Beijing 100039, China.
Abstract:A pot and two field experiments were conducted to analysis of changes in competitive
ability and yield stability of old and modern winter wheat cultivars and to attempt assessment whether
a relationship is existed between competitive ability and yield stability. Two water regimes were
imposed to compare competitive effects and yield stability under adequately watered and
water-limited conditions. The results are similar in both pot and field experiment. Competitive ability
was investigated using de Wit replacement series. In mixture, the old cultivar had a higher relative
yield and spikes number compared with that of modern cultivar, the dry matter content per stem of
modern cultivar tended to decrease with increasing proportions of old landrace. The difference
between old and modern cultivar mentioned above showed that the competitive ability of modern
cultivar was lower than that of old cultivar in mixture. In monoculture, the modern cultivar had higher
grain yield, yield components (except spike number), water use efficiency (WUEg) and harvest index
than the old cultivar under two water regimes. However, the reduced grain yield from water adequate
to water limited condition in old cultivar was higher than that of modern cultivar in both pot and field
experiment. Greater grain yield of modern cultivar was associated with higher harvest index,
thousand-kernel-weight and lower R: S ration. Water consumption over the entire growing period was
significantly higher in old cultivar under difference moisture, and mainly different between two
cultivars was observed before anthesis period. The competition superiority of old landrace was mostly
due to the higher plant height, LAI, tiller capability and larger root system. Post-anthesis accumulation
of dry matter was greater in modern cultivar under water limited condition, no difference between two
cultivars when water condition improved. The dry matter remobilization and its contribution to grain
yield for modern cultivar were lower than old landrace. Our study demonstrated that higher
competitive ability in old landrace leading to increase growth redundancy (both above-ground and
belowground biomass), which resulting in more grain yield was lost when water condition was
unfavorable, and contributed to decrease the yield stability. In conclusion, the current study suggested
that breeder should pay more attention to select new cultivars with low competition and high yield
stability, which may lead to superior performance in semi-arid area.
keywords: Triticum aestivum, Semi-arid Loess Plateau, Growth redundancy, Above-ground biomass,
Root system, Post-anthesis dry matter dynamics.
*
Corresponding author, FengMin Li, Email: fmli@lzu.edu.cn
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