Relación de los modelos respecto a escalas urbanas reales

From 1985 to the present, barley breeding led by the Zhejiang AAS was listed as a key project by the Chinese Ministry of Science and Technology. The Hangzhou National Barley Improvement Center, established at the Zhejiang AAS in 2001, has greatly promoted barley breeding in China. Other major institutes involved in barley breeding include Zhejiang University (formerly Zhejiang Agricultural University) in Hangzhou, Nantong Agricultural Research Institute, Yancheng Agricultural Research Institute and Yangzhou University in Jiangsu

Province, Shanghai Academy of Agricultural Science, Tibetan Agricultural and Animal Husbandry

Academy in Lasa, Qinghai Academy of Agricultural Science in Xinning, Gansu Academy of Agricultural Science in Lanzhou, and Hongxinnong Agricultural Research Institute in Heilongjiang. The Chinese Academy of Agricultural Science is responsible for germplasm collection and characterization.

The mission of the National Barley Improvement Center includes:

(1) Collection, preservation, and documentation of barley genetic resources, both local and introduced, and establishment of a barley genetic resources database.

(2) Genetic resource evaluation and analysis;

identification and evaluation of the main characteristics of barley resources; genetic analysis and evaluation of potential parents.

(3) Exchange and creation of new genetic resources among all barley breeding groups and creation of elite materials for cultivar assessment.

(4) Improvement of breeding methods, including research on heterosis, improvement of traditional breeding methods, identification of disease resistance, early generation

determination of quality, improved mutation induction technology, and biotechnology.

(5) Selection and promotion of new cultivars:

selection of malting and feed barley cultivars with good quality, high yield potential, disease resistance, and stress tolerance, and their promotion in appropriate cultivation areas.

(6) Industrialization of new cultivars as a sound base for malting and feed barley production;

establishment of mechanisms for combining cultivar selection, seed production, processing, and promotion and marketing of new cultivars.

(7) Training and international collaboration for the exchange of local and foreign barley germplasm;

establishment of a national barley network.

6.1 Malting quality improvement

The aim of breeding high quality malting barley is to increase malt extract, diastatic power, and amylase activity, and to decrease protein content while improving grain appearance and physical characteristics. In the near future, malt extract is expected to reach 82%, diastatic power will reach 280-300 WK, and the protein content of malting barley grown in northern China will be less than 12%.

6.2 Feed barley

The primary aim of the feed barley breeding program is high yield and quality with emphasis on increasing grain protein and lysine contents while decreasing beta-glucan and fibrin contents. In the near future, feed barleys are expected to have protein content approaching 13-15%, lysine content up to 0.5%, and beta-glucan content less than 2.5%.

6.3 Yield potential

Research will focus on traits likely to produce high yields, such as short stature, multi-spike characteristics (including large spikes and large grain), and high harvest index. Multi-rowed and naked feed barley genotypes with high yield

potential will be important, as naked types with high protein and low fibrin contents are well suited for feed. In the near future, the yield potential of feed barley should reach 1,200-9,000 kg/ha.

6.4 Disease resistance

Resistance to Fusarium head blight, barley yellow mosaic, and powdery mildew are essential for the production of high yielding malting and feed barleys. Fusarium head blight is the greatest constraint to the production of malting barley.

Resistance is quantitatively inherited and strongly influenced by environment; fortunately, it is easier to achieve in two-row than in six-row genotypes.

6.5 Tolerance to abiotic stress

Barley is more tolerant to salt, waterlogging, drought, and acidity than other cereals. There is huge potential to develop tolerant cultivars for the under-utilized eastern and southern areas of China that are subject to one or more of these constraints.

6.6 New breeding methods

The methods used to improve barley are typical of self-pollinated crop breeding programs.

Conventional methods may include pedigree, mutation, backcross, intercross bulk-population, doubled haploid, single seed descent, and hybrid approaches. With developments in molecular biology, marker-assisted selection and genetic transformation are beginning to be used in breeding.

Combining these new methods with conventional methods will provide further genetic gains.

Barley is an under-utilized crop in China. Barley improvement is relatively new, but it has already contributed to the malting and feed industries, while retaining its traditional role as a minor food crop.

It is now recognized that the qualities required for each of these end-uses are very different, and that separate improvement programs are required for each. There are also areas where barley production could expand without replacing or competing with other crops, and breeders should exploit barley’s special attributes of abiotic stress tolerance and promote its use in areas where such stresses limit other cereal crops. Increased production will meet the rapidly expanding demand for malting and feed barley, as living standards improve, and perhaps even reduce the current high reliance on imported grain for both uses. However, this will be achieved only with competitive, high yielding, high quality cultivars, and well organized grain handling, storage, marketing, and transport infrastructure.

References

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Feng, Z.Y., Zhang, Y.Z., Li, M., Kuang, S.F., and Xu, T.W. 2001.

Review of studies on barley nucleo-cytplasmic interaction type male sterility in China. Barley Science in China 5:

13-17 (in Chinese).

Huang, Z.R. 2001. Review of barley production and scientific research in China in the 20th century. Collections of Barley Research Papers in China 5: 1-6 (in Chinese).

Lu, L.S. (ed.). 1996. Chinese Barley Science. China Agriculture Press, Beijing, China (in Chinese).

Ma, D.Q., and Li, Y.Q. 1999. Excellent wild barley relatives’

resources in Tibet and Qinghai plateau in China.

Collections of Barley Research Papers in China 4: 1-5 (in Chinese).

Shao, Q.Q., Rong, J.K., Li, A.S., Deng, W.Q., and Lin, X.Y.

1991. Study on relationship between inheritance of male sterility and genetic distance between crossed species of barley. Collections of Barley Research Papers in China 2:

53-54 (in Chinese).

Sun, D.F., Xu, T.W., Jiang, H.R., and Zhao, L. 1995. Selection and genetic analysis of nucleo-cytoplasmic male sterile l1ne 88bcms in barley. Scientia Agricutura Sinica 28(3):

1-36 (in Chinese).

Wang, L., Xue, Q., Newman, R.K., and Newman, C.W. 1993.

Enrichment of tocopherol, tocotrienol, and oil in barley by milling and pearling. Cereal Chemistry 70: 499-501.

Xu, T.W., and Feng, Z.Y. 2001. Origin of cultivated barley in China with reference to the explanations of the Chinese classical words Lai Mu. Collections of Barley Research Papers in China 5: 18-22 (in Chinese).

Xu, Z.W., Deng, B., Liu, M.H., Fei, D.B., Li, Y.M., and Xu, Y. 2004. Effects of different enzymes on reducing the viscosity of barley, wheat and rye. Acta Agriculturae Zhejiangensis 16: 21-24 (in Chinese).

Yang, J.M., Shen, Q.Q., Wang, J.M., and Zhu, J.H. 2003. The production, demand and strategy of barley in China.

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Zhang, M.S., Zhang, J.Y., Jiang, X.P., Wang, J.R., Wu, C., and Guo, J. 1998. Current situation and tendency of research on exploitation of barley (Hordeum vulgare) heterosis. Acta Agriculturae Jiangxi 10: 81-85 (in Chinese).

Zhao, L.Q. 1993. Review on barley improvement in Zhejiang province. Barley Science 3: 1-3 (in Chinese).

1. Introduction

Triticale is a synthetic species created by combining the genomes of wheat and rye. Its creation was inspired by wheat’s own evolution. Hexaploid wheat (genomic formula: 2n=42=AABBDD) evolved through two natural inter-specific hybridization events followed each time by spontaneous chromosome doubling. This brought together the genomes of three diploid wild species, namely Triticum uratu (genome AA); a representative of the Aegilops group (genome BB) not unlike Aegilops speltoides; and Aegilops tauschii Cosson. (genome DD) (Wilson, 1876; Meister, 1921;

Gustafson et al., 2009). The addition of each genome resulted in marked improvements in both yield and nutritional quality.

Allopolyploid triticale can be produced through man-made crosses between wheat (AABB if tetraploid wheat is used, or AABBDD if hexaploid wheat is used) and rye (RR). The resulting hexaploid (AABBRR) or octoploid (AABBDDRR) triticales are characterized by large, complex genomes (Blakeslee, 1937; Muntzing, 1979). Because of potentially high biological yields, good nutritional quality, high levels of disease resistance, and wide adaptability, triticale has shown great potential as a new cereal crop in China and elsewhere (Zillinsky and Borlaug, 1971; Sun and Zhang, 1996; Sun, 2002; Sun et al., 2002).

In China, triticale research started in the 1950s. The first variety was exhibited around the country in 1970, and released for commercial production in 1976 (Bao, 1981; Bao and Yan, 1993; Sun and Wang, 1986).

Before 1995, triticale was used mainly as a food crop planted in high altitude, cold mountainous areas of southwestern and northwestern China because of its stress tolerance and disease resistance. After 1995, with changes in the Chinese agricultural structure and adjustments in cereal breeding objectives (from

breeding cultivars only for food, to developing green forage cultivars and dual-purpose forage and grain cultivars for food and feed), triticale began to be used as a fodder crop (Table 1) as its high biological yields and good nutritional qualities became increasingly known (Sun et al., 1996; Wang and Sun, 2002, 2003a, 2003b).

The area sown to triticale in China was around 73,000 ha in 2008. Today triticale is an important fodder crop throughout the country, and is expanding rapidly in the Yellow and Huai Valleys, northern China plain, southern and lower reaches of the Yangtze River, and northwestern China.

2. Development and evolution of triticale