Inheritance of pseudo-self compatibility in self-incompatible garden and greenhouse chrysanthemums, Dendranthema grandiflora Tzvelv

Summary Self incompatibility (SI) can be used to alleviate costly hand emasculation and pollination in F₁ hybrid chrysanthemum seed production. SI, however, disrupts the progression of inbreedig (selfing or full-sib mating). Consequently, inbreds are selected for breakdown of the SI system or the presence of pseudo-self compatibility (PSC). PSC inbreds, recombinant inbreds, and noninbred cultivars were selfed and/or intercrossed to determine PSC expression across environments and generate 1–3 inbred generations (I₁–I₃). Percent PSC ranged from 0–68.8% for inbred parents, 0.2–99.7% for recombinant inbreds, and 0.6–25.7% for noninbred cultivars. There was no indication of end-of-season PSC. The majority of parents (78%) were classified as low PSC and this trend continued in the I₁ (70.1%), I₂ (65.6%), and I₃ (83.6%) generations; mid PSC was rarer (11.9–18.8%) and high PSC the least common (4.5–15.6%). PSC distributions were primarily continuous, rather than discrete, indicating quantitative inheritance. In several inbred families, 100% of the I₁ individuals were SI; this was not correlated with parental PSC level. Inbred families derived from selfing low and mid PSC parents were the most likely to reach extinction due to inbreeding depression. High PSC was not highly heritable, since I₁ progeny were predominantly SI or had low to mid PSC levels. Most 153-1 values for PSC:SI segregations (1:1, 1:3, 3:1) were not significant at the 5% level. Realized heritability (H _R ) estimates for PSC ranged from a low of 0.05% to 10.19%, although increased H _R values did not account for inbreeding depression or genetic mechanisms preventing selection for high PSC. The highest individual %PSC increased over the high parent with SI × low PSC or SI × mid PSC parents in all cases; progeny means did so only in SI × low PSC. Low × low crosses were split evenly between an increase and decrease in progeny or highest individual mean. Since all low × low crosses and low selfs produced 43–50% of the progeny with PSC levels higher than the parents, it appears that most low parents possess some unexpressed PSC genes. Mid PSC parents responded similarly to low PSC genotypes. An increase in PSC was found when crossing SI × PSC parents, illustrating a threshold effect. PSC × PSC crosses (high × low, low × low) produced SI, low, and mid PSC I₁ individuals but did not show a heterotic effect, since the PSC parents had already surpassed the PSC threshold. Selfing high PSC parents, however, suggested different genetic control. Progeny and highest individual means behaved the same; 83% decreased and 17% remained the same for PSC levels. The drop in PSC indicated non-additive gene action. Thus, the PSC threshold with additive gene action holds when selection for higher PSC levels is being done from low and mid PSC parents, but once high PSC levels are obtained, non-additive gene action prevails.Abbreviations self pollinated - H _R Realized Heritability - PSC Pseudo-Self Compatibility - SC Self Compatibility - SI Self Incompatibility     

In vitro induction of tetraploids in colchicine-treated cocoyam plantlets

A self-compatible (SC) variant of a wild diploid potato species, Solanum chacoense, which is normally self-incompatible (SI), was investigated for the nature and genetics of self-compatibility. It was crossed with a SI cultivated diploid potato species, S. phureja. The F₁ progeny segregated SC vs. SI. Diallel crosses were made among 15 F₁'s. Self-compatibility was tested in a selfed family of a parental SC variant and in sib-mated and selfed families of F₁ progeny. All the data suggest that there is a single dominant gene (Sli) with sporophytic action inhibiting S gene expression in the pollen. Plants having a ‘Sli’ gene, produce pollen which is compatible to its own parent and plants with similar S genes. The ‘Sli’ gene has been maintained in a heterozygous condition through eight selfing generations (S₈) implying that dominant homozygotes might be associated with lethality. This revised version was published online in July 2006 with corrections to the Cover Date.     

甘蓝SI相关基因BoCDPK14的克隆与分析

甘蓝自交不亲和性(self-incompatibility,SI)是柱头对相同单倍型的花粉产生的排斥或抑制反应。钙依赖蛋白激酶(calcium-dependent protein kinase, CDPK)是植物面对逆境信号时参与抗逆反应的重要元件。本文通过甘蓝自花授粉0～60min的柱头转录组数据分析,成功地筛选到一个受自花授粉诱导上调表达的基因BoCDPK14,该基因与拟南芥中参与植物逆境信号传导的钙依赖蛋白激酶基因高度同源。BoCDPK14基因开放阅读框1599bp,编码一种具有533个氨基酸残基的亲水性蛋白,可在大肠杆菌胞质中被诱导表达,其相对分子质量为60.4kD,表明BoCDPK14为活性胞质蛋白。该基因起始密码子上游2000bp的核苷酸序列中含有胁迫反应、激素反应、代谢调节等应答元件。BoCDPK14在甘蓝柱头、花粉、花蕾、花瓣和叶片中表达,且柱头中的表达量低于花粉。荧光定量PCR结果证实,BoCDPK14在0～60min的表达变化趋势与转录组分析结果一致。通过酵母双杂交发现,BoCDPK14蛋白激酶结构域与谷氨酸受体通道蛋白BoGLR2.8d存在相互作用,表明BoCDPK14可能是参与SI反应过程的新蛋白。本研究结果表明BoCDPK14可能作为Ca~(2+)信号元件参与甘蓝柱头响应花粉刺激的分子过程,这为甘蓝自交不亲和的进一步研究和利用提供了新内容。     

用化学方法克服油菜等芸苔属(Brassica)作物自交不亲和性的研究 Ⅳ.用NaCl克服自交不亲和性的机理初探

研究结果表明,NaCl克服油菜等芸苔属作物自交不亲和性的机理主要在于使柱头蛋白质变性;在识别反应中,柱头可能是主动的起关键作用的一方,花粉可能是被动的起次要作用的一方;用NaCl只处理花粉不能有效克服自交不亲和性;NaCl克服自交不亲和性的效应似乎是可逆的。     

Inheritance of Temperature-Induced Pseudocompatibility in Rye

The differences between pseudocompatible seed produced by selfing self-incompatible plants of rye (Secale cereale L.) at high temperatures were investigated. The isozyme loci Prx7 and β-Glu which are linked to the two self-incompatibility loci S and Z, were used as markers. Different alleles of S and Z strongly influenced the pseudocompatibility. For the locus S at 30°C a scale of varying efficiency of the S alleles was found. Furthermore, it proved possible to select one population with increased and one with decreased pseudocompatibility at high temperatures. The population with high pseudofertility was still incompatible under normal temperature conditions. Such selected material facilitates the production of inbred lines of self-incompatible rye material, which can be a useful tool in an efficient rye breeding programme.     

Lilium x ‘Black Beauty’—a potential bridging hybrid in Lilium

Summary Lilium Black Beauty, a rare intersectional hybrid previously reported sterile, was re-examined for pollen and ovule fertility. No pollen tubes were detected following incubation of styles pollinated with Black Beauty pollen. However, embryos varying in size from small globular to long boat-shaped and only rarely associated with endosperm, were found in 0.1–1.0% of the ovules in Black Beauty pistils pollinated with Oriental or Aurelian division lilies. Aseptic extraction and culture of these embryos on a nutritive medium resulted in growth, germination, and plantlets. It is apparent that with embryo culture, Black Beauty has unique value as a species bridge in that it accepts pollen of both Oriental and Aurelian lilies, two of the major commercial lily divisions.Scientific Journal Series Paper Number 9197 of the Minnesota Agricultural Experimental Station.     

Overcoming self-incompatibility in Ipomoea cairica by IAA

Summary Ipomoea cairica Sweet (Convolvulaceae) exhibits sporophytic self-incompatibility. This has partially been overcome under in vitro conditions, by treating the pollen and/or stigma with 10^-5–10^-1M indole-3-acetic acid (IAA), the optimum being 10^-2M. The self-pollen. which otherwise does not even stick to stigma. germinates after self-pollination provided only one or both the partners are treated. The pollen tubes not only penetrate stigmatic papillae but also traverse the whole length of the style, at least in optimum experimental combinations.     

New self-incompatibility alleles in apricot (Prunus armeniaca L.) revealed by stylar ribonuclease assay and S-PCR analysis

Apricot (Prunus armeniaca L.) shows gametophytic self-incompatibility controlled by a single locus with several allelic variants. An allele for self-compatibility (S_C) and seven alleles for self-incompatibility (S₁–S₇) were described previously. Our experiments were carried out to ascertain whether the number of allelic variants of apricot S-locus was indeed so small. Twenty-seven apricot accessions were analysed for stylar ribonucleases by non-equilibrium pH gradient electrofocusing (NEpHGE) to determine their S-genotype. To validate the results of electrofocusing, the applicability of the S-gene-specific consensus PCR primers designed from sweet cherry sequences was tested. NEpHGE revealed 12 bands associated with distinct S-alleles in newly genotyped cultivars. Cherry consensus primers amplified 11 alleles out from 16 ones, which indicated that these primers could also recognize most of the S-RNase sequences in apricot, and provided an efficient tool to confirm or reject NEpHGE results. By combining the protein and DNA-based methods, complete or partial S-genotyping was achieved for 23 apricot accessions and nine putatively new alleles (provisionally labelled S₈–S₁₆) were found. Their identity needs to be confirmed by pollination tests or S-allele sequencing. This study provides evidence that similarly to other Prunus species, the S-locus of apricot is more variable than previously believed.     

Pollen and pollination experiments. V. An empirical basis for a mentor pollen effect observed on the growth of incompatible pollen tubes in pear

Summary The self-incompatible pear cultivar Doyenne du Comice was selfed with the aid of the mentor pollen technique (self pollen mixed 1:1 with compatible pollen) and the pioneer pollen method (compatible pollen applied 14 h in advance of the self pollen). Observations on tube growth in the style showed that inviable methylated pollen was ineffective either as mentor or pioncer pollen, having no effect on the performance of the self pollen which stopped growing at about one quarter of the style from the stigma. Calculations made on the basis of the obtained data indicated that the viable untreated or irradiated pioneer and mentor pollen, the former somewhat better than the latter, aided the self pollen tubes to reach the base of the style.     

Self-Fertile Doubled Haploid Plants of Perennial Ryegrass (Lolium perenne L.)

The self-fertility of chromosome-doubled haploid lines of perennial ryegrass and their first (I₁) and second (I₂) generation selfed offspring was studied. The overall seed set was low, 0—0.4 seeds per spike, as would be expected for chromosome-doubled haploids of a self-incompatible species. Nevertheless, significant genetic variation was observed for self-fertility within three of the six lines studied. Within one line, three I₂-clones showed increased self-fertility, while in two other lines one and three I₁-clones, respectively, showed significantly increased self-fertility. Selection, during selfing, of rare pollen grains with mutations in the self-incompatibility system could explain the observed changes and would lead to a general breakdown of self-incompatibility in Lolium perenne during repeated selfing of chromosome-doubled haploids.