提高普通大麦离体单倍体胚出苗率的研究

 本试验以普通大麦（Hordeum vulgare L，2n=2x=14）×球茎大麦（H. bulbosum L.,2n=2x=14）产生的普通大麦单倍体胚为材料，研究了胚龄（胚大小）、基因型及B#-5培养基中加不同物质对其离体培养时出苗的影响。结果表明：⒈每升培养基加5克活性碳可以提高出苗率，四个供试基因型的提高幅度为7.2%-24.3%；⒉最佳接种胚龄受温度等因素的影响，3月底至5月初温室条件下的最佳胚龄为14天左右，大田为17-19天或更长；⒊培养基中加15-30mg/L多效唑（PP333）时，出苗率最高，但不同基因型有不同反应；⒋不同基因型单倍体胚的出苗率有明显差异；⒌培养基中加活性碳和PP333还可使苗生长健壮。因此，将适当胚龄的单倍体胚接种在B#-(5)+5g/L活性碳+15-30mg/L PP333的培养基上，可以产生较高频率的单倍体苗。     

大麦‘花22’不同生育期的饲用品质及呕吐毒素含量

为了明确大麦‘花22’不同生育期的饲用品质。以‘花22’为材料,分别在拔节期、灌浆后期、乳熟期和完熟期进行刈割,测定其常规营养成分、脂肪酸组成、氨基酸组成及呕吐毒素含量。结果表明：从拔节期至完熟期,随着生育期的延长,粗蛋白、粗脂肪、钙、磷含量显著下降(P<0.05);干物质和木质素含量显著增加(P<0.05)。脂肪酸组成中C18:3n3含量、氨基酸组成中的氨基酸总量、必需氨基酸含量、呈味氨基酸均显著下降(P<0.05)。粗纤维、中性洗涤纤维、酸性洗涤纤维含量呈阶段性波动,其中从拔节期至灌浆后期,粗纤维、中性洗涤纤维、酸性洗涤纤维含量显著增加(P<0.05),灌浆后期期达到最大值,之后显著下降(P<0.05)。完熟期检测出呕吐毒素含量为560.50 μg/kg,拔节期、灌浆后期和乳熟期未检测出呕吐毒素。综上各生育期比较,拔节期‘花22’的营养品质最好,粗蛋白、粗脂肪含量达到最大值(20.44%、4.71%),粗纤维含量最低(20.40%)。拔节期‘花22’的营养品质与黑麦草相近,无显著性差异(P>0.05)。灌浆后期、乳熟期和完熟期‘花22’的营养品质显著低于黑麦草(P<0.05)。拔节期、灌浆后期‘花22’的营养品质高于带穗玉米秸秆,完熟期的‘花22’的营养品质低于带穗玉米秸秆。在闽北种植的‘花22’完熟期不能作为青饲料使用。     

Comparison of Anther Culture and Hordeum bulbosum Method for the Production of Doubled Haploid in Winter Barley I. Production of Green Plants

The relative response to two-major techniques of producing haploids in barley – anther culture and the Hordeum bulbosyum method – were compared using seven F₁ hybrids from a winter barley breeding programme. Both techniques were Applied to the same plants with the same number of replications. 358 viable green plants were obtained from 420 spikes ot donor plants used: 147 through anther culture and 211 through the H. bulbosum method. From the data analysis we found that the response to the two techniques was not significantly different, genotype effect and genotype × technique interaction were highly significant. The possibility of combining the two techniques in a doubled haploid production programme is discussed.     

The Effectiveness of Vernalization of Immature Embryos of Winter Wheat var. Grana as Related to Age and Exogenous Phytohormones

Starting from the 10th day after pollination, immature embryos of winter wheat var. Grana were isolated and then vernalized for 4 to 8 weeks on Murashige and Skoog nutrients containing BAP (0.5 or 2 mg/dm³), NAA (0.5 or 2 mg/dm³), or GA₃ (5 or 20 mg/dm³). Vernalized seedlings were cultivated in a greenhouse and the number of days to the heading of individual plants as well as the percentage of plants capable of generative development were estimated. The lower limit of size for 50 % survival of embryos strongly depended on the phytohormone used: from 0.9 mm in control, 1.1 mm in nutrient containing BAP, 1.2 mm for NAA, up to 1.7 mm in nutrient with GA₃. Exogenous GA₃ was lethal for embryos younger than 18 days but induced elongation of older embryos. Embryos isolated 2.5 to 4 weeks after pollination showed minimal requirements for the length of vernalization. BAP increased the percentage of heading plants originated from the youngest embryos. GA₃ improved partial vernalization, strongly increasing the percentage of heading plants, but did not change the time from the end of vernalization to heading. It has been postulated that GA₃ increases number of plants capable of overcoming the threshold of induction of generative development but does not accelerate the flowering process. Hormonized plants showed no deformation of generative development. As the effectiveness of vernalization increased, the heading of plants was faster but they were shorter, forming spikes with a smaller number of spikelets and producing fever lateral shoots. The very young embryos probably have in reserve sufficient amounts of auxins and gibberellins and therefore exogenous GA₃ decreases their viability or even exerts a deleterious effect. However, as the embryos' ageing, gibberellin starvation develops. This being especially pronounced during vernalization. The de novo synthesis or activation of gibberellins takes place during the second stage of vernalization. This is why exogenous hormone improves the effectiveness of partial vernalization, though it is not possible to substitute by gibberellins the vernalization requirements of immature embryos.     

Comparison of Anther Culture and the Hordeum bulbosum Method for the Production of Doubled Haploids in Winter Barley

The comparison, between the efficiency of anther culture and the Hordeum bulbosum method in barley was extended to the chromosome number distributions of all planes derived from the two techniques and the proportions of fertile doubled haploid plants which survived until maturity. The frequencies of haploid and spontaneously doubled haploid plants which were useful for practical breeding purposes were found to be around 90 % for both techniques. The remainder consisted of polyploid, mixoploid and aneuploid variants in the case of microspore-derived plants and diploid interspecific hybrids in the progeny of the H. bulbosum method. The ploidy level distributions of the microspore- and H. bulbosum-derived plants appeared to be independent of the genotype of the donor. There were no significant differences between techniques regarding the proportions, of plants which survived a severe winter and the production of fertile doubled haploid plants. Both techniques can therefore complement each other in a breeding programme and their relative merits are discussed. Possible ways of improving doubled haploid production in barley are suggested for increasing its use in breeding schemes.     

三种有机磷农药对大麦毒性效应的研究

使用浸种和浸种加喷施两种方法,研究了3种有机磷农药———马拉硫磷、对硫磷和久效磷在不同浓度条件下对大麦幼苗生长发育、根细胞分裂及叶绿素含量的影响。结果表明,3种有机磷农药对大麦种子萌发和根伸长均有一定的抑制作用,抑制程度随浓度增大而加强。幼苗根伸长比种子萌发对有机磷农药胁迫更为敏感。不同浓度的有机磷农药处理后均能抑制根细胞分裂,使有丝分裂指数下降。浸种法和浸种加喷施法都能使大麦叶片叶绿素含量降低,但浸种加喷施法对叶绿素合成的影响明显大于浸种法。3种有机磷农药对大麦幼苗的毒性程度依次为马拉硫磷>对硫磷>久效磷。     

应用小孢子离体培养技术培育大麦新品系

以大麦F1、F2代为供体材料,通过技术优化,建成了大麦小孢子培养高频再生技术程序。利用大麦小孢子加倍单倍体育种技术平台,二年内就可获得种性稳定的株系,四年内即可参加新品种区试。经过田间严格鉴定与选择,育成了大麦新品系“花98-11”和新株系“花01-3”、“花01-12”。     

Genetic Variability for Grain Yield and Protein Content in Barley and Its Modification by Net Blotch

Protein content, yield and 1000-grain weight of healthy and net blotch-diseased plants were studied in a diallel cross programme concerning nine different varieties of barley (Hordeum vulgare L.). F₁ hybrids and their parents were grown in the field in two randomized block design experiments each with three replications (three inoculated and three non-inoculated plots). General and specific combining abilities were determined for yield, protein percentage, 1000 grain weight, protein yield, and non-protein yield. A high genetic variability for the traits studied was observed. Non-protein yield and 1000-grain weight decreased significantly in inoculated plants where protein yield was not affected. Significant general and specific combining abilities were observed for all traits. Values for general and specific combining abilities were, in some cases, significantly modified by net blotch of barley. This indicates that attention must be paid to the danger of drawing conclusions in quantitative genetics studies dealing with both diseased and healthy plants.     

Radiation-Induced Nullisomy in Hordeum vulgare L.

A plant with drastically reduced vigour was observed in a population of diploid barley (Hordeum vulgare) raised from seeds exposed to gamma radiation. Cytological studies revealed that the plant was nullisomic with 2n = 12. At meiosis, regular formation of 6 bivalents was observed. The plant was totally sterile and produced neither stainable pollen nor seed.     

Effectiveness of Twenty-Four Barley Resistance Genes Against Powdery Mildew (Erysiphe graminis DC f. sp. hordei Em. Marchal) in Spain

Twenty-four near-isogenic barley lines, with a cv.‘Pallas’ background, carrying different mildew resistance genes were subjected in 1987, 1989 and 1990 to natural infection by the pathogen at several different and contrasting Spanish sites in order to study its virulence. The virulence genes proved to be geographically grouped into three regions: western (Valladolid), southern (Sevilla) and northern and northeastern (Navarra, Lleida and Girona). The mildew population of Lleida was more variable when compared with Navarra and Valladolid. Overall, the most effective resistance genes were: Ml-a13 + Ml-(Ru3), mlo and Ml-(1402).