In vitro androgenesis of wheat: from fundamentals to practical application

Wheat anther cultures have a history of almost 30 years and are nowemployed efficiently in many countries of the world for the developmentof doubled haploid lines for breeding. The present paper discusses keyquestions of the elaboration and perfection of the method: cytologicalaspects of in vitro androgenesis, the conditions required for theembryogenic development of microspores and the applicability of anthercultures in the Martonvásár wheat breeding programme.     

Assessment of yocoboue wild oil palm (Elaeis guineensis Jacq.) from Côte d'Ivoire

Following a survey involving wild oil palm groves in Côte d’Ivoire as a whole in 1968, 17 parents were chosen at Yocoboué (southernCôte d’Ivoire). Agronomic performance of the 17 parents was assessed through Deli × Yocoboué hybrids in 3 trials grown at La Mé (Côte d’Ivoire), Mondoni and La Dibamba (Cameroon).When compared to the Deli × La Mé progenies used as controls, the Deli × Yocoboué hybrids produced 91% for total bunch weight and86% for oil yields. However, the genetic variability within the Deli × Yocoboué progenies allows to select individual progenies as productive as the Deli × La Mé controls, for breeding purposes. A study of major agronomic traits led to the choice of parent YO 11 T , which combines the largest number of favourable traits. On average, Deli × Yocobouéprogenies have slower vertical growth and are susceptible to Fusarium wilt, except 2 parents (YO 3 T and YO 9 T), which seem to be resistant.     

萝卜花药培养技术研究

通过单倍体育种途径可快速获得纯合材料,增加有益性状的选择几率,加快育种进程。花药培养是获得单倍体的有效途径之一,已在十字花科芸薹属作物上取得巨大成功。但关于萝卜花药培养的报道极少。以15个不同类型的萝卜品种为试材,研究了花药离体培养中胚状体的诱导及再生。结果表明:基因型是限制花药培养成胚的关键因素,15个品种中,有4个品种获得了胚状体及再生苗。同时植株生长条件也对胚状体的形成产生影响。采用流式细胞仪(FCM)鉴定了再生株的倍性,再生株群体的倍性组成比较复杂,以二倍体为主。     

Plants regenerated from embryo cultures of an apomictic clone of Kentucky bluegrass (Poa pratensis L. ‘Baron’) are not apomictic in origin

Plants were regenerated from tissue cultures of embryos dissected from seeds that were harvested from a self-pollinated clonal selection of Kentucky bluegrass (Poa pratensis L.) ‘Baron’, an apomictic cultivar. Plants were regenerated from 35 embryo-derived callus cultures of the 3280 embryos that were plated. Flow-cytometric (FCM) and RAPD-marker analyses were performed to determine if regenerants were or were not apomictic in origin. Fifteen regenerants with a 3c DNA content were classified as arising from 2n + n aberrant embryos, which was a higher frequency than expected, based on a chi-square analysis. Of the remaining 20 regenerants with a 2c DNA content, a chi-square test showed that all could have arisen from n + n sexually-derived embryos, based on the observed segregation of n + n regenerants, which fit the expected 3:1 ratio of dominant:recessive RAPD-marker phenotypes. The apparent lack of regenerants of apomictic origin, and implications for genetic transformation and breeding of Kentucky bluegrass are discussed.     

Possibility of exploiting the Yd2 resistance to BYDV in spring barley breeding

The effects of the Yd2 gene on tolerance to barley yellow dwarf virus (BYDV) and other agronomically important characters in spring barley were evaluated in a set of randomly selected doubled haploid (DH) lines of an‘Igri’/‘Atlas 68’ cross and three crosses between CIMMYT Yd2 materials and the Czech malting barley ‘Akcent’. The cleaved amplified polymorphic site (CAPS) diagnostic marker Yd2 was used for identification of the Yd2 gene and this analysis showed high agreement with the results of field infection tests. Yd2 lines exhibited significantly lower symptom scores and lower reductions of some grain yield characters, but their resistance level was not consistent over the years. The presence of secondary stresses (high temperature/drought) in 2000 led to relatively higher sensitivity to BYDV infection, strengthened by the long life cycle of genotypes. In cases where secondary stresses were mild (in 2002), the longer life cycle significantly increased sensitivity to BYDV infection only in the absence of the Yd2 gene (in susceptible genotypes). The examination of different vegetative, grain yield and malting quality characters separately for groups of Yd2 and non‐ Yd2 lines did not show any evidence of adverse effect of the Yd2 gene on any character.     

作物育种品系试验四种分析方法比较

用水稻、小麦和大豆的8个三重复品系试验的产量结果, 进行了作物育种品系试验的三种分析方法与随机完全区组分析(RB)的比较. 此三种分析方法分别是, 行列区组分析(RC)、行列区组及近邻小区分析(RCN)和行列区组及以小区丛数为协变量的协方差近邻分析(COV). 结果表明, 以误差均方作为相对效率指标, RC、 RCN、 COV相对于RB的平     

系祖轮配对维持并提高豫州褐壳蛋鸡Ⅲ系生产性能的研究

对豫州褐壳蛋鸡Ⅲ系采用系祖间轮配的选配方法，经过连续3个世代的选育，开产日龄推迟5．72d，开产平均蛋重减少0．87g，72周龄平均蛋重增加2．82g、蛋数增加8．62枚，蛋品质维持在较高水平，蛋壳颜色变深。说明对已育成的纯系采用系祖间轮配的选配方法，可以维持并提高其生产性能。     

Breeding strategies for early soybeans in Belarus

Yield and other agronomic traits in soybean depend on the growth habit. The best maturity group, 00 indeterminate cultivars, compared with semi determinate cultivars for 3 years, out yielded the latter by 9%, possessed greater height and node number but somewhat stronger lodging and better lower bottom pod set. Maturity did not differ significantly within the samples. Correlations were recorded between the yield, growth type and node number. Indeterminate cultivars, in general, require fewer days to start flowering than determinate cultivars. This character is useful in the development of cultivars tolerant to a moderate drought in the second half of the summer. Thus, the most likely model of maturity group 00 variety for Belarus may be an indeterminate, early flowering, full season cultivar.     

Flower induction in seedlings of Aster novi-belgii and selection before and after vegetative propagation

Bolting and flowering of Aster novi-belgii seedlings as well as correlations between characteristics within seedling populations and between seedlings and their vegetatively propagated offspring were investigated in order to improve breeding efficiency. In seedlings of A. novi-belgii, flower induction was observed without vernalization. Seedlings initially formed a rosette, but bolting was a prerequisite for development of a normal flowering shoot. Bolting was promoted by long photoperiods as compared to short days. The shortest time from sowing to anthesis was recorded when plants were grown under long photoperiods until the main stem was at least 5 cm long, and then moved to short photoperiods. A large variation in time to anthesis, plant height, branching ability, and flower size and color was found among the seedlings within all crosses. Magnitude and significance of correlations between some characteristics varied among crosses. The more consistent correlations seem mainly to be due to natural courses of plant growth and development. High correlations between seedling characteristics and their vegetatively propagated offspring were only found for flower hue. Lower, but significant correlations were found for flower color intensity, plant height and branching ability. There were no significant correlations for the time-to-anthesis between the two groups of plants. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetic and non-genetic factors affecting germination and vitality in spring barley seed

Germination of eight spring barley varieties, grown in two years at eight different locations in State varietal trials in the Czech republic, was analysed. All the combinations were tested under optimal conditions for germination as recommended by ISTA and also at low temperatures (5 and 10°C), and underwater stress (- 2 and - 4 bar). Germination under low temperature and water stress was considered as a character of seed vitality. Varieties in nearly all experiments were a significant source of variation and their relative contribution to the total variation was higher for vitality (5.7–38.7%) than for germination (2.0–4.3%). However, the percentage of germination were not related to the percentage of vitality. The location in nearly all the experiments caused the greatest variation and the impact was greater for germination than for vitality. Provenance effects were different for germination and for vitality; grains harvested in the lowland had the highest germination values, but not the highest vitality values. The results should encourage breeding for seed vitality and some reconsideration of provenance effects on seed vitality.