Male-sterility in the grain amaranth (Amaranthus hypochondriacus ex-Nepal) variety Jumla

Summary Twenty naturally occurring male-sterile plants were recovered from a normal population of the grain amaranth, variety Jumla. The identification of the male-sterile plants is possible during anthesis and after flowering. The male-sterility in this variety is conditioned by a single recessive nuclear gene ms.This research was supported by Grant No. AMA-KE-4-83-22 (CRG GRANT) from the National Academy of Science, USA. Reprint requests to V.K. Gupta.     

Sex modification in Actinidia deliciosa var. deliciosa

Summary The aim of the trial was to determine whether growth regulators and injuries could affect sex expression in the cultivated kiwifruit. Growth substances (NAA, BAP, GA, ethephon, ABA, TIBA, and CCC) were applied at 1% concentration in lanolin (w/w) to shoots of 17-year old plants of the staminate clone Matua and the pistillate clone Hayward. Injuries consisted in shoot defoliation or removal of a ring of phloematic tissue from the laterals. Both the application of growth regulators and injuries were done about 5 weeks before anthesis. In the pistillate clone, no treatment resulted in overcoming pollen grain sterility; ABA and GA mereased the stigma-style number as well as the density of papillae on the stigma surface. A positive correlation was found between stigma-style number and pedicel length (r=0.660). In the staminate clone, pollen grain viability was significantly altered by treatment; the highest (79.2%) and lowest (10.3%) values were recorded for ABA and GA, respectively. A negative correlation was found between pollen grain viability and pedicel length (r=–0.648). As a general rule, treatments which depressed pollen grain viability allowed the development of a variable number of styles. About 20 styles were consistently produced when GA was applied; the gibberellin-caused feminization of kiwifruit was confirmed in a repeated trial. The data collected also suggest that sex expression can be slightly changed by injuries; contrariwise, rather good results can be achieved by using a growth regulator earlier in the season or before flower initiation.     

籽粒苋AhNAD-ME的序列特征与表达

NAD(P)-苹果酸酶催化苹果酸氧化脱羧,产生丙酮酸和CO₂,伴随NAD(P)的还原。在C₄植物中,苹果酸酶参与了C₄光合作用。本研究对克隆的双子叶C₄植物籽粒苋NAD-苹果酸酶基因(AhNAD-ME)编码的氨基酸序列进行了生物信息学分析,结果表明, AhNAD-ME具有苹果酸酶的完整功能域,包括苹果酸N端结构域和苹果酸酶的NAD结合结构域;进化树表明, 该序列属于NAD-ME的α亚基,该亚基定位于线粒体基质中。半定量RT-PCR分析表明,该基因主要在叶片和茎中表达,表达量随光照时间延长而增加。将AhNAD-ME基因重组到原核表达载体pEASY-E1中,电击法转化到大肠杆菌Transette (DE3)菌株中,IPTG诱导其高效表达,表达的融合蛋白的分子量与预期相符,主要以包涵体形式存在。     

Estimates of genetic variability and heritability for vegetative and reproductive characters of kiwifruit (Actinidia deliciosa)

The results of this study indicated a great deal of genetic variation in a number of characters of horticultural interest in kiwifruit seedling populations, and therefore, a potential to improve kiwifruit by vine selection. High narrow sense heritability was shown for pedicel length(0.62) and flowering duration (0.50) in male vines, and pedicel length (0.67),floral shoot percentage (0.54), leaf length-width ratio (0.64), fruit elongation (0.64) and fruit weight (0.52) in female vines. For these traits, selection of superior seedlings should lead to rapid genetic improvement in these populations. This revised version was published online in August 2006 with corrections to the Cover Date.     

Manova and discriminant analyses of phenotypic data as a guide for parent selection in kiwifruit (Actinidia deliciosa) breeding

Evaluation of seedling populations assists in identifying those plants most desirable as parents for a breeding programme. A multivariate analysis of variance (Manova) showed that the seedling populations from 6 kiwifruit (Actinidia deliciosa) crosses differed in their overall merit. Discriminant functions were then used to identify the characters most powerful in distinguishing between populations. The populations were placed in order of their function scores which represent overall merit, and the superior populations were determined. The results showed that `Bruno' was a superior female parent for the production of seedlings with high discriminant function scores for floriferousness (male offspring)and productivity and high vitamin C content (female offspring). One male parent D-1-20 was consistently superior to D-1-6 the other male parent. This revised version was published online in July 2006 with corrections to the Cover Date.     

The role of pollen and stigma in determining the level of partial self-compatibility in brussels sprouts

Summary Brussels sprouts inbred plants, homozygous for the same recessive S-allele, were intercrossed in all combinations and the number of pollen tubes penetrating the stigmas of such crosses measured. The results of five such experiments showed that pollen as well as stigma is significant in determining the number of pollen tubes counted. It was also found that the capacity of a plant's stigmas to permit pollen tube penetration was independent of the capacity of its pollen to penetrate other plants' stigmas. Variation in pollen tube production between pollens of the plants tested was often greater than that between their stigmas.     

Disc polyacrylamide gel electrophoresis of pollen proteins in the oil palm (Elaeis)

Summary A preliminary screening of proteins and isozymes in the oil palm was investigated with a view to using the data in discriminating oil palm fruit forms. Protein and enzyme staining was carried out using pollen tissue. Repeatable bands of proteins which showed reproducable variation in banding patterns were obtained. Low percentage similarities between the groups compared for protein banding patterns were obtained. A single enzyme esterase extracted from pollen tissue exhibited repeatable variation between species only. It was intended to obtain information that would supplement morphological markers through electrophoretic data in the identification of different fruit forms of the oil palm.     

Inheritance of taste characters and fruit size and number in a diploid Actinidia chinensis (kiwifruit) population

We investigated the variability and inheritance of taste components and fruit size and number in a seedling population of diploid Actinidia chinensisPlanch. We found significant variation in all characters measured. Narrow-sense heritability estimates were high for vitamin C content, titratable acidity (TA), soluble solids content (SSC), fruit weight and dry matter content (DM), but low for glucose content, quinic acid content, and fruit number per vine. The genetic correlations between sugars (except myo-inositol), acids (except quinic acid), TA, vitamin C content, SSC and DM tended to be positive and moderate to high. However, correlations between these characters and fruit weight tended to be negative and moderate to high. The standardised coefficients () of multiple regression showed that SSC was highly dependent on the levels of fructose content, sucrose content and TA. Estimates of relative selection efficiencies (E) suggested that selection using SSC could be an efficient and convenient alternative to direct selection for improvement of sugar levels in kiwifruit. However, selection strategies based on SSC need to take account of its moderate negative correlation with fruit weight. Male and female parents useful for improving acid and sugar composition and fruit size were identified. One family was outstanding, as it combined large fruit size with high levels of SSC and DM.     

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.     

Variation in the storage proteins of peas in relation to sulphur amino-acid content

Summary A cellulose acetate electrophoretic technique has been used to characterise the storage proteins present in pea seeds in order to try and determine the proportions of proteins present which are enriched in sulphur amino-acids. Some of the eight varieties examined were shown to differ in their proportions of the various storage proteins. When the proteins were separated and estimated quantitatively and also characterised by their sub-unit composition, it was shown that cellulose acetate electrophoresis of crude protein extracts or of whole globulins did not give the degree of resolution required. The procedures which have to be undertaken in order to obtain this information are considered, and the difficulties of incorporating them into a plant breeding programme discussed.     

Genetic variation for isozyme genes and proteins in spanish primitive cultivars and wild subspecies of Lens

Summary An analysis of the variability for genes encoding seven isozyme systems and storage proteins in a collection of cultivated and wild accessions of Lens is reported. The collection, which is part of the Spanish INIA Cenebank, contains the ssp. culinaris, orientalis, odemensis, nigricans and ervoides, and presents a high degree of genetic diversity both within and between the accessions. A total 25 loci were examined; of these, 18 were polymorphic (the 7 genes encoding storage proteins, and the following isozyme loci: Acp-1, Acp-2, Cpx-1, Cpx-2, Aat-p, Aat-m, Lap-1, Mdh-2, Mdh-3, Mdh-4 and 6pgd-p) and 7 were monomorphic (Aat-mb, Aat-c, Mdh-1, Mdh-5, 6pgd-2, Pgm-c and Pgm-p). The phylogenetic relationships between subspecies were analyzed using the allelic frequencies. The study suggests that orientalis and odemensis share more biochemical characters than the other subspecies, and that those subspecies keep an intermediate position between Lens culinaris and Lens nigricans.     

The site of action of the crossability genes (Kr 1, Kr 2) between Triticum and Secale. I. Pollen germination,pollen tube growth,and number of pollen tubes

Summary Seven genotypes of common wheat (Triticum aestivum L.) were crossed with rye (Secale cereale L.) in order to find the site or sites of action of the crossability genes, Kr ₁ and Kr ₂, of wheat. The data obtained, by fluorescence microscopy, were compared to the controls (wheat x wheat). The results indicate that the crossability genes have little effect on pollen germination and on the time taken for the pollen tubes to reach the microphyle, irrespective of their crossabilities with rye. The number of pollen tubes reaching the microphyle is, however, affected by the Kr-genes, as high crossable genotypes have more pollen tubes than the low crossable ones. There was a high correlation between the mean number of pollen tubes at the micropyle with seed set, which also reflects the crossability. The Kr-genes seem to manifest themselves in the retardation and inhibition of pollen tube growth between the style base and the top of the embryo sac, where the effect is most distinct in the low crossable genotypes.     

Similarities and differences between Amaranthus species and cultivars and estimation of outcrossing rate on the basis of electrophoretic separations of urea-soluble seed proteins

Wheat-rye translocation line (2BS/2RL) has been developed for resistance to biotype L of Hessian fly and agronomically useful traits. AFLP analysis using 64 primer pairs was conducted in order to identify 2RL-specific polymorphisms between “Coker 797” (non-2RL), near-isogenic line (NIL) carrying 2RL, and “Hamlet”. Nine primer combinations identified twelve reproducible polymorphic fragments in the NIL carrying 2RL. These twelve fragments were cloned and sequenced with an aim towards converting AFLP markers into sequence tagged sites (STS). A comparison of the 12 sequences with non-redundant accessions in the NCBI database using the BLAST search option indicated that one fragment of approximately 200 bp in length (amplified using primer combination E+AAC / M+CTA) was highly homologous with the rye-specific repetitive sequence R173-1 and Wis-2-lA, a retrotransposon-like element in wheat. Two STS primers (SJ07 and SJ09) out of twelve STS primer sets enabled the detection of polymorphisms between Coker 797 and NIL carrying 2RL. In order to verify whether the polymorphism detected by primers SJ07 and SJ09 was in fact the result of the presence of 2RL, additional plant material was examined. Amplified products of about 260 bp fragment with the SJ07 primer set were generated in rye cvs.“Chilbohomil” and “Jochunhomil”, triticale experimental line Suwon 15, and wheat experimental line K-14 (1AL/1RS & 2BS/2RL), as well as NIL carrying 2RL and Hamlet, but not in Coker 797 (non-2RL), “Keumgangmil” (non-translocation wheat), KS92WGRC17 (PI592729 /;/ 6BS/6BL-6RL), KS92WGRC19 (P1592731 /;/ 4BS/4BL-6RL), “TAM200” (1AL/1RS), and “Siouxland” (1BL/1RS). Our data suggest that primer set SJ07 amplifies a “2RL-specific” fragment of diagnostic value. This revised version was published online in August 2006 with corrections to the Cover Date.     

The interaction between compatible and self-incompatible pollen of apple and pear as influcenced by their ratio in the pollen cloud

Summary The production of self-seed was investigated in apple and pear with the aid of viable and compatible mentor/ pioneer pollen in relation to the proportion of self-imcompatible pollen present in the pollen cloud.Treatments consisted of mixtures of compatible and self-incompatible pollen at ratios of 1:1, 1:2 and 1:9 applied once or twice or followed by self-pollination. Selfing only, whether once or twice, produced virtually no fruits or seeds, while mixed pollinations did. Generally, fruit set tended to decrease and the self-seed to increase with increasing amounts of self pollen in the pollinations.The pioncer-pollen method (compatible in advance of self pollen) appeared more effective than the mentor pollen method (compatible and self pollen mixed). The use of viable instead of dead mentor/pioneer pollen causes competition for the ovules with the self pollen, but has the advantage that, in addition to some self-seed, other seeds are formed which, e.g. in apple, are necessary to keep the fruits on the tree until harvest.Fruit set was moderately reduced at ratios of compatible pollen to self pollen not exceeding 1:9 with pear and 1:5 with apple which constitute maximal ratios in practice as regards pollinator trees: trees of the main cultivar. In fruit orchards and probably in nature with other species, the interaction between compatible and self pollen may result in more self-seed, and so suggests that inbreeding played a greater part in the evolution of self-incompatible species, than the meager results of articial self-pollination imply.     

Cytoplasmic male-sterility and source of pollen influence the expression of resistance to sorghum midge, Stenodiplosis sorghicola

Sorghum midge, Stenodiplosis (Contarinia) sorghicola (Coquillett), is an important pest of grain sorghum, and host plant resistance is an important aspect of control of this pest. This research investigated how cytoplasmic male-sterility and source of pollen influence the expression of resistance to sorghum midge. Sorghum midge emergence was significantly lower in panicles of midge-resistant and midge-susceptible cytoplasmic male-sterile lines when pollinated with AF 28 - a midge-resistant restorer line, than those pollinated with Swarna - a midge susceptible restorer line, indicating the presence of xenia effects. Maintainer lines (B-lines) of midge-resistant parents had significantly lower numbers of eggs and larvae than the B-lines of midge-susceptible parents. Male-sterile lines of the both midge-resistant and midge-susceptible lines were equally susceptible, indicating that resistance to sorghum midge is influenced by factors in the cytoplasm of the B-line. These findings will have an important bearing on the production of hybrids with resistance to insects. This revised version was published online in August 2006 with corrections to the Cover Date.     

Incompatible pollen tube growth and protein composition in styles of Japanese pear following high temperature treatments

Summary Immersing the excised-prepollinated styles of self-incompatible Japanese pear, Pyrus serotina Rehd., into distilled water at 45°C for 1.5–2.5 min promoted the growth of self-pollen tubes; both the number of styles penetrating the pollen tubes through styles to cut ends and of pollen tubes protruding from cut ends were increased. The subsequent growth of the protruded pollen tubes on agar media was also enhanced by the treatments. Treatments at 40°C did not promote the growth of self-pollen tubes and those at 50°C led the styles to necrosis. In the stylar proteins analyzed by isoelectricfocusing polyacrylamide gel electrophoresis, several changes in banding pattern were found following the heat treatment; one of the bands was a glycoprotein that increases in quantity in developing styles as self-incompatibility of the style becomes stronger (Hiratsuka et al., 1986). This protein band was stained more weakly by Coomassie Brilliant Blue-G250 dye. Antigenic substances in the styles examined by immunodiffusion seemed not to be denatured by high temperature treatments.Abbreviations IEF-PAGE isoelectricfocusing polyacrylamide gel electrophoresis - CBB Coomassie Brilliant Blue     

Resistance to Tomato spotted wilt virus introgressed from Lycopersicon peruvianum in line UPV 1 may be allelic to Sw-5 and can be used to enhance the resistance of hybrids cultivars

The breeding line UPV 1 developed from the PE-18 accession of Lycopersicon peruvianum collected in Huallanca, Ancash, Peru, shows resistance to TSWV. Mechanical inoculation and thrips transmission were used to study the inheritance of TSWV resistance of this line. UPV 1resistance is controlled by a dominant gene. The penetrance of this resistance gene was complete in mechanical inoculation and incomplete when thrips transmission was used. Linkage tests between the resistance genes of lines UPV 1 and RDD (Sw-5), indicated allelism. A molecular analysis using a SCAR marker tightly linked to Sw-5 also supported this hypothesis. In heterozygotes the level of resistance expressed in UPV 1 is higher than that expressed in RDD (Sw-5), indicating that the resistance from UPV 1 may be of higher value for the development of commercial hybrids. This revised version was published online in July 2006 with corrections to the Cover Date.     

Analysis of pollen tube growth in situ to investigate self-incompatibility in the wild potato Solanum commersonii

Summary Pollen tube growth was investigated in a diallelic crossing design with seven genotypes of the diploid wild potato species Solanum commersonii, accession O/S UR-9, CIP 762459. Pollen tube growth in the style was recorded using a combined quantitative and qualitative evaluation scale. Clear-cut differences in pollen tube growth behavior in compatible and in partially or completely incompatible crosses were detected. Diallelic crossing of the seven randomly chosen genotypes, intercrossing within two progeny families, and backcrossing of two progeny populations to the parents revealed the existence of a one-locus gametophytic system of stylar incompatibility. The S-allele status of all genotypes investigated was determined.     

Occurrence of 2n and jumbo pollen in the Brazilian ginseng (Pfaffia glomerata and P. tuberosa)

An analysis of microsporogenesis was carried out in four populations of Pfaffia tuberosa (2n=4x=68) and in ten populations of P. glomerata(2n=2x=34). Monads, dyads and triads were reported at high frequency in all populations of P. tuberosa. In P. glomerata, on the other hand, only four populations presented monads, and at low frequency. Dyads and triads were observed in both species, albeit at a higher frequency in P. tuberosa populations. Certain abnormalities of spindles in the second division, such as sequential and tripolar spindles, led to triad formation by the rejoining of two chromosome sets. The precise causes of monad and dyad formation have not been found during meiosis, although evidence exists that dyads originated by omission of second meiosis and monads by omission of both meiotic divisions. This revised version was published online in July 2006 with corrections to the Cover Date.     

Factors affecting haploid production in wheat using the Hordeum bulbosum system. 1. Genotypic and environmental effects on pollen grain germination,pollen tube growth and the frequency of fertilization

Summary A quantitative examination of pollen grain germination and pollen tube growth within the overy wall was made in selected wheat × tetraploid H. bulbosum hybridizations, to investigate the effect of the wheat and the H. bulbosum genotype on these characters. As expected, variation at the known crossability loci had no effect on pollen grain germination. The frequency of pollen tube penetration of the ovary wall was, however, severely reduced when the dominant alleles were present. Pollen tube penetration was nevertheless observed in 3 of the 110 ovaries examined of the non-crossable cultivar Highbury. The H. bulbosum genotype had a much smaller effect on these characters, but significant differences between the clones were observed in the numbers of pollen tubes initially penetrating the ovary wall. Although two H. bulbosum genotypes showed no significant differences in the number of ovaries with pollen tubes at the base of the ovule, significant differences in the frequency of fertilization were observed. The possible cause of this discrepancy is discussed.The frequency of fertilization in crossable wheat × H. bulbosum hybridizations was improved by the application of gibberellic acid within 10 minutes of pollination, and reduced by an increase in the ambient temperature from 20°C to 26°C. Fertilization following the pollination of non-crossable wheat genotypes was not affected by either of these factors.