Attributes of wheat cultivars for late autumn sowing in genes expression and field estimates

Due to the growing interest in Central and Eastern Europe on cropping of wheat in optional late autumn terms, called facultative, genetic research and field evaluation were taken on four spring cultivars: Tybalt (NL), Monsun (DE), Ostka Smolicka (PL) and Bombona (PL), currently being recommended by breeders. The PPD gene analyze, expression level of dehydrine genes (WCS120 and WDHN13) in cooling test, and qPCR for RNA isolation and analyses of WCS120 and WDHN13 gene expression at the BBCH12 stage of wheat were estimated. Molecular analysis of PPD-D1 gene confirmed the presence of photoperiod sensitive allele ppd-D1b in all tested genotypes. The highest level of NRE WCS120 gene was detected in cultivars Tybalt and Bombona. Two-year field experimental study assessed the growth, development and productivity of facultative and spring crops of studied cultivars. Based on our results from field experiments and result of molecular analysis of alleles of PPD-D1 gene, the tested genotypes can be considered as potentially facultative genotypes.     

Comparison of selection methods among and within full-sibling progenies in Urochloa humidicola

Hybridization in the Urochloa humidicola breeding programme allowed to explore the genetic variability of the apomictic sources and, thus, to obtain new sexual and apomictic parents with compatible ploidy and/or superior progenies. However, given the high variability arising from crosses, there is a need to adopt efficient selection strategies among and within progenies. The aim of this study was to compare the selection methods among U. humidicola progenies with (t-BLUP) and without (BLUP) the weighting based on prediction error and subsequent selection within progenies by individual simulated (BLUP_IS) or optimal individual BLUP. We evaluated seventy-one U. humidicola full-sib progenies from biparental crosses between nine sexual and ten apomictic parents. The experiment was set up in an incomplete block design with 64 blocks of 15 plots each, consisting of individual plants. Seven consecutive cuts were made and the traits total dry-matter, leaf dry-matter and regrowth scores were measured. Genetic variance was expressive for all traits. The selection procedure among progenies of U. humidicula based on t-BLUP proved to be more advantageous regarding the use of BLUP not weighted by the prediction error, resulting in higher selection gains, taking as reference the optimal procedure of the individual BLUP. Furthermore, the use of BLUP_IS allowed an optimized selection of hybrids, allowing the breeder to explore with variable selection intensity the genetic variability within the selected full-sib progenies based on relative genetic merit.     

变叶海棠（M．toringoides（Rehd．）Hughes）无融合生殖胚胎发育的特征与结果

对３ｘ变叶海棠（Ｍ．ｔｏｒｉｎｇｏｉｄｅｓ（Ｒｅｈｄ．）Ｈ．）无融合生殖作了胚胎学观察。其无融合生殖方式是体细胞无孢子生殖，胚胎发育具胚囊的复合性、起源空间多位性、发生时间的持续性与滞后性。花粉败育、无融合生殖的结果大多种子败育或早期退化。     

蒲公英无融合生殖特性初探

以丹东蒲公英为研究材料,利用常规压片法对去雄切柱头和在自然授粉条件下的种子根尖染色体进行观察,同时采用石蜡切片法观察丹东蒲公英胚珠发育情况。结果表明:丹东蒲公英为二倍体,人工去雄切柱头后的丹东蒲公英子房切片中可以观察到二分体的形成,一个退化,另一个经有丝分裂形成八核胚囊,卵细胞逐步发育为成熟胚,表明丹东蒲公英无融合生殖类型为二倍体孢子生殖。此外,丹东蒲公英去雄切柱头后的结籽率高达90.34%,发芽率为84%。     

无融合生殖研究及其在高粱育种中的应用前景

无融合生殖是作物育种的新领域 ,与其它育种方法相比它的历史较短 ,但它独特的生殖方式和在作物育种中的重大意义引起了作物育种界的广泛关注与重视 ,特别是一些牧草作物实现了杂种优势固定 ,给作物杂种优势利用带来了新的革命。文章对作物无融合生殖类型、遗传方式以及在育种中的应用进行了概述 ,并阐述了高粱无融合生殖的研究现状、兼性无融合生殖系×兼性无融合生殖系育种方法在固定高粱杂种优势中的前景 ,以及高粱无融合生殖用于育种和生产的优势。认为玉米、水稻等作物如能用无融合生殖代替目前的杂种优势利用方式 ,其贡献和意义是巨大和深远的     

苹果属植物无融合生殖特性——文献综述

介绍了国内外苹果属中无融合生殖种类;综述了国内外学者对这些种无融合生殖特性的研究成果，包括兼性无融合生殖习性、无性胚形成方式、遗传方式、染色体倍性和同工酶表现；简述了无融合生殖在科研及生产的应用现状和潜力。     

Genetic variation in the agamic species complex of Pennisetum section Brevivalvula (Poaceae) from West Africa: ploidy levels and isozyme polymorphism

Some characteristics of the species complex Pennisetum section Brevivalvula are polyploidy and apomixis. Four euploidy levels (x = 9) were assessed by DAPI-flow cytometry for 304 plants of the section, distributed among five species: P. hordeoides (2n = 36, 54), P. pedicellatum (2n = 36, 45, 54), P. polystachion (2n = 18, 36, 45, 54), P. setosum (2n = 54), and P. subangustum (2n = 18, 36, 54). The geographical distribution of the ploidy levels seems to be related to major ecological zones of West Africa. The hilly regions displayed a higher ploidy diversity than the others; diploid populations of the annual species P. polystachion and P. subangustum were found. Genotypic variation expressed by isozyme polymorphism did not show any significant difference between the diploid, sexual populations and the polyploid, apomictic populations of these two species. This revised version was published online in July 2006 with corrections to the Cover Date.     

Apomictic frequency in sorghum R473

Summary Apomixis has been reported in a few lines of sorghum, among them R473 which was originally reported to be an obligate apomict. Although this line has multiple embryo sacs, the frequency of apomictic seed formation has not been determined because a progeny test has not been possible. R473 does not cross as a female with other lines except when its own pollen is present. In the present study mutations were induced in R473 by hydrazine and irradiation. Crosses were made between male-sterile mutants as females and normal R473 as males. Plants of R473 produced F₁ hybrids sexually, thus indicating that they were not obligate apomicts. These F₁'s also reproduced sexually, as indicated by segregation for male sterility and male fertility in F₂ progenies.     

Grass inflorescence and spikelet culture: An appraisal

Summary Techniques of inflorescence and spikelet culture have been used for three major cereals. In maize, the influence of hormones on sexuality has been demonstrated. For wheat and barley the influence of supplying carbohydrate and nitrogen on grain content has been explored. Although in vitro seed setting is less efficient than in vivo the resulting grains, from optimal treatments, are in almost all respects normal or nearly so. Culture media to achieve this are precisely defined.In reviewing this work a major concern has been to highlight an elegant system of enquiry but at the same time to indicate the remarkably small area of interest to which it has been applied. As a prelude therefore to a consideration of the technical achievements, the range of spikelet form, and more particularly, function are examined. The aim is to encourage the application of inflorescence and spikelet culture to a much wider range of topics than hitherto.     

Pollen and coenocytic microspore germination in male-fertile and malesterilemsl soybean

Summary Light and fluorescence microscopy were used to study coenocytic microspore germination from male-sterile (ms1 ms1) soybean plants. Anther squashes from male-sterile plants revealed that a low frequency of natural coenocytic microspore germination occurred in male-sterile anthers of four independent lines; [ms1-North carolina (T260H),ms1-Urbana (T266H),ms1-Tonica (T267H), andms1-Ames (T268H)]. Abnormalities such as giant tubes, branched tubes, tubes with swollen areas, and multiple tubes were observed from coenocytic microspores from all four lines. The Urbana line, however, demonstrated a higher percentage of coenocytic microspore germination than did the other three lines. Flowers of the Urbana line from both malefertile and male-sterile plants, as well as gynoecia pollinated with coenocytic microspores from sterile plants, were used for in vivo studies. Pollen-tube growth appeared normal in male-fertile plants. In contrast, coenocytic microspore tubes rarely were observed in gynoecia from male-sterile plants or in gynoecia from malefertile plants that had been artificially cross-pollinated withms1 ms1 plants. Few tubes from coenocytic microspores were observed in the vicinity of the micropylar region. A low frequency of seed set was achieved in the greenhouse on Urbana male-sterile plants grown in the absence of male-fertile plants. Thus, we believe either that some gametes from coenocytic microspores are able to participate in fertilization at low frequency or that apomixis occurs inms1 ms1 plants.Joint contribution: Agricultural Research Service, U.S. Department of Agriculture, and Journal Paper No. J-12310 of the Iowa Agriculture and Home Economics Experiment Station, Ames IA, 50011 USA. Project 2471.