Genetic Diversity Analysis of Tibetan Wild Barley Using SSR Markers

One hundred and six accessions of wild barley collected from Tibet, China, including 50 entries of the two-rowed wild barley Hordeum vulgare ssp. spontaneum (HS), 29 entries of the six-rowed wild barley Hordeum vulgare ssp. agriocrithon (HA), and 27 entries of the six-rowed wild barley Hordeum vulgare ssp. agriocrithon var. lagunculiforme (HL), were analyzed using 30 SSR markers selected from the seven barley linkage groups for studying genetic diversity and evolutionary relationship of the three subspecies of Tibetan wild barley to cultivated barley in China. Over the 30 genetic loci that were studied, 229 alleles were identified among the 106 accessions, of which 70 were common alleles. H. vulgare ssp. spontaneum possesses about thrice more private alleles (2.83 alleles/locus) than HS (0.93 alleles/locus), whereas almost no private alleles were detected in HL. The genetic diversity among-subspecies is much higher than that within-subspecies. Generally, the genetic diversity among the three subspecies is of the order HS > HL > HA. Phylogenetic analysis of the 106 accessions showed that all the accessions of HS and HA was clustered in their own groups, whereas the 27 accessions of HL were separated into two groups (14 entries with group HS and the rest with group HA). This indicated that HL was an intermediate form between HS and HA. Based on this study and previous works, we suggested that Chinese cultivated barley might evolve from HS via HL to HA.     

转TrxS基因啤酒大麦种子中硫氧还蛋白h与淀粉酶活性变化

导入TrxS基因后,转基因大麦籽粒的硫氧还蛋白h活性明显提高;淀粉酶活性也明显提高,其中α-淀粉酶活性在开花后30d提高了3倍以上,随着籽粒的发育,转基因对α-淀粉酶活性影响作用减少,对β-淀粉酶活性的影响有同样的趋势;转基因大麦种子发芽势明显提高。说明TrxS基因有望改善啤酒大麦的制麦特性和品质特性。     

保护性耕作条件下旱地农田麦-豆双序列轮作体系的水分动态及产量效应

保护性耕作(conservationtillage)能够减少水土流失、提高耕地产量,是一类具有生态保护意义的持续性农业耕作形式。2002年至2004年在定西旱地农业地区进行了保护性耕作条件下旱地农田春小麦豌豆双序列轮作土壤水分动态及产量效应的试验研究,结果表明:保护性耕作能够显著改善0～200cm土层土壤贮水量及含水量,随着降水量的增多土壤对降水的保蓄能力增强。在降水较少年份免耕秸秆覆盖的这种作用表现突出,而在降水充沛的年份免耕地膜覆盖则更具优势。耕层土壤水分因受降水等因素的影响而变化剧烈,耕层以下土壤水分变幅相对较小。播种期、五叶期及收获期土壤具有较高含水量,而开花期土壤含水量则较低。在两种轮作体系中,播种期春小麦和豌豆免耕秸秆覆盖处理0～50cm土层含水量分别较常规耕作增加28%、26%和11%、23%,降水生产效率较常规耕作提高了17.79%～26.81%。在春小麦豌豆轮作体系中免耕秸秆覆盖处理的作物产量(春小麦 豌豆)及水分利用效率分别为3420kghm2和8.11kg(hm2·mm),较常规耕作分别提高26.81%和25.39%。     

AMMI模型在旱地春小麦稳定性分析中的应用

基因型与环境的互作(GEI)决定了作物在多变环境下性状的稳定性。AMMI模型是一种将方差分析和主成分分析结合于一体,能更有效分析GEI、进而评价基因型稳定性和环境对基因型差异分辨力的有力工具。利用AMMI模型对10个品种(系)、13个试点组成的全国旱地春小麦区域试验产量资料分析表明,试点间平均产量变幅为396.6~4050.2 kg.hm-2,现代品种间的平均产量变幅为1318.6~2315.6 kg.hm-2;基因型间、环境间和GEI引起的产量变异达到极显著水平,三者的变异平方和分别占总处理平方和的6.2%、70.3%、23.5%,表明环境和GEI对产量变化的影响远大于基因型。用前3个代表了90.8%GEI信息的显著主成分计算基因型稳定性参(Di)和试点分辨力(Dj),基因型间Di最大相差达3倍、而试点间Dj最大相差19倍;属于高产、稳产的品种有:定西35、西旱1号、定丰889,而在这两方面均表现最差的品种为蒙麦35号。有些品种对某些试点有特殊适应性,局部推广价值也大。     

In vitro regeneration of cereals based on multiple shoot induction from mature embryos in response to thidiazuron

The in vitro competency of mature cereal embryos (winter, spring and durum wheats, oat, barley and triticale) was assessed for direct multiple shoot production on culture media containing the plant growth regulators, thidiazuron (TDZ) and/or 6–benzylaminopurine (BAP). Mature embryos of CDC Dancer oat showed the best response, with 69 shoots per explant on culture medium containing a combination of 4.5 μM TDZ and 4.4 μM BAP. TDZ alone induced about 16 shoots per explant from the oat. Among the wheat genotypes, durum wheat showed the most number of shoots (35) per explant on culture medium containing 4.5 μM of TDZ and 4.4 μM of BAP. With TDZ alone, shoot regeneration for durum wheat ranged from 27–32 shoots per explant. The regeneration frequency from the three winter wheat genotypes ranged from 11–25 shoots per explant and was highest on culture medium containing 9.1 μM TDZ and 4.4 μM BAP. The latter culture medium was also effective for a triticale genotype, inducing 34 shoots per explant. The regeneration from mature embryos of barley genotypes ranged from 5–9 shoots per explant. The mature embryos of all the cereals tested could be used for in vitro regeneration with TDZ and TDZ+BAP combinations.     

Development of microsatellite markers for the barley stem gall midge,Mayetiola hordei (Diptera: Cecidomyiidae)

Ten microsatellites were isolated from the barley stem gall midge, Mayetiola hordei. Polymorphism at each locus was tested on 40 individual midges, among which 34 were collected on barley and six on wheat crops in Tunisia. Six loci were polymorphic with the number of alleles ranging from two to seven. The observed heterozygosity varied between 0.025 and 0.2. These microsatellite loci revealed a strong effect of host plant on the population genetic structure of M. hordei.     

Effects of Rate and Source Organo-Mineral Material on Forage Yield and Nutritive Value of Barley-Pea Mixed under Arid Conditions

Cereal-legume intercropping plays a vital role in the subsistence food production system that prevails in the arid regions. It not only provides profitable crop productivity for agricultural communities but also plays an important role in improving soil fertility. Therefore, the present research was conducted to assess the effect of the organic and mineral fertilizers on the forage yield and nutritional value in barley-pea intercropping system. The results revealed that the quality of forage grass is significantly influenced by both organic and inorganic fertilizer. Thus, organic fertilizer application has significantly influenced the dry matter (DM), crude ash (CA), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF). Among the treatments, organic fertilizer added at rate of 35 m⁻³ ha⁻¹ produced the maximum fresh and dry matter in barley and peas. In addition, the same level of organic fertilizer also improved silage composition by significantly increasing the protein and fiber content and showed highest the values. Based on overall results, it is concluded that organic fertilizer treatment (35 m⁻³ ha⁻¹) has the potential as an effective strategy to improve the productivity and nutritional quality of the barley-pea intercropping system in arid areas. The results revealed that organic fertilizer can be utilized in sustainable agricultural as a source of nutrients for numerous various crops under arid conditions.     

Host-parasite Interactions of Pratylenchus scribneri on Selected Crop Plants

Greenhouse tests were conducted to determine the effects of soil temperature and texture on development of Pratylenchus scribneri and the pathogenicity and reproductive rates of this nematode on selected crop plants. In a sandy loam soil, greatest numbers of P. scribneri were found at 30 and 35 C on sudangrass and sugarbeet, respectively. In a silty clay loam, the nematode reproduced best at 35 C on sugarbeet. Higher populations of P. scribneri were found in the sandy loam than silty clay loam soil at corresponding temperatures. In a pathogenicity test, top and root growth of sudangrass and barley were suppressed by the nematode, whereas no significant growth inhibition was found on wheat and alfalfa. Tests with other vegetable and field crops indicated wide variance in nematode reproduction.     

The occurrence of barley yellow dwarf viruses in CIMMYT bread wheat nurseries and associated cereal crops during 1988–1990

Enzyme-linked immunosorbent assay (ELISA)-based surveys of the occurrence of five barley yellow dwarf virus (BYDV) serotypes (MAV, PAV and SGV in “Group 1”; RPV and RMV in “Group 2”) in CIMMYT bread wheat nurseries and other small grain crops in various locations world-wide were undertaken in 1988, 1989 and 1990. The objective was to investigate the relative occurrence of BYDV serotypes in areas relevant to CIMMYT cereal breeding programs. Overall, MAV and PAV serotypes predominated in the samples collected, though their relative frequencies depended on the location. SGV serotypes were uncommon in most locations. Group 2 serotypes occurred widely, but RMV serotypes were more common than RPV serotypes.     

Soret absorption of intermediate(s) in protochlorophyllide to chlorophyllide photoreduction trapped at low temperature

Absorption spectra at ca 100 K from 400 to 750 nm and fluorescence emission spectra at 77 K from 600 to 750 nm were obtained from: 1) etiolated leaves of the H-ordeum vulgare L. (barley) mutant albozonata 2 and SAN 9789-treated Avena sativa L. (oat) with low levels of carotenoids, and 2) preparations of protochlorophyllide holo-chrome from Phaseolus vulgaris L. cv. Commodore (bean).
This allowed clear resolution for the first time of the Soret bands of the green pigments before and after light-induced accumulation of intermediate(s) in protochlorophyllide to chlorophyllide photoreduction and after conversion of the intermediate(s) to chlorophyllide by warming the samples to 233 K in darkness. Although the intermediate(s) differ(s) in absorption and fluorescence in the red wavelength region from both protochlorophyllide and chlorophyllide, the extinction in the Soret band is not distinguishable from that of chlorophyllide. These observations indicate that the C7-C8 double bond in ring IV of protochlorophyllide has been altered in intermediate(s) accumulated at low temperature in intense light, such that the transition state exhibits the character of a π complex.