Inheritance of flower color in Dendranthema grandiflora Tzvelev. (Chrysanthemum morifolium Ramat.) using cultivars and inbreds. II. Vacuole pigmentation

Summary Dendranthema grandiflora Tzvelev (Chrysanthemum morifolium Ramat.) garden cultivars Vulcan, with deep red ray florest, and Superior, with orange ray petals, were crossed as female with 16 inbred clones and the progeny assessed visually for flower color in 3 environments. Intensity of vacuole pigmentation in ray florets appeared to vary continuously. Evaluation was facilitated by placing plants in 7 color classes ranging from red, the most intense, through orange, an intermediate intensity, to yellow, the apparent lack of vacuole pigmentation. A simple hexaploid model with additive gene action, suggested by the 7 color classes, was inappropriate, as more than 50% of the plants in Vulcan families were red and more than 60% of the plants in Superior families were orange. Comparing evaluations of parental clones in 2 glasshouse and 2 field environments and considering data from an experiment, in which progeny first classified in the glasshouse were reevaluated in the field, revealed substantial shifts in classification. In the glasshouse, more individuals appeared in the red and orange classes, while field evaluation placed more individuals in classes adjacent to red and orange. However, the predominance of progeny in the color class of the common parent, that is, red for the Vulcan and orange for the Superior families, occurred in both glasshouse and field. Plants scored as other than red appeared in crosses between Vulcan and 3 red inbreds, suggesting that red ray petals are not conditioned by a homozygous genotype. The orange of Superior and orange progeny may be due to a single dominant gene causing mosaic-like distribution of red vacuole pigmentation over yellow plastid pigmentation. Because cloned genotypes were classified differently in diverse environments, critical genetic analysis of vacuole pigmentation will require cloned progeny and multiple-environment evaluation.     

Inheritance of resistance to powdery mildew (Erysiphe graminis f. sp. hordei) in eleven primitive barley varieties

The inheritance of the powdery mildew resistance of eleven primitive barley varieties was investigated. crosses with varieties with identified resistance genes revealed that at least three different genes are present in a group of six genotypes from Greece (Hor736, Hor847, Hor878, Hor1159, Hor1379 and Hor1873) and one from Turkey (Hor1188). One dominant gene is common to these seve genotypes and in the Greek accessions a second gene is present. The expression of this second gene was respectively dominant in the crosses with Hor736 and Hor1159, recessive in the crosses with Hor878 and Hor1873, and depended on the employed powdery mildew isolate in the crosses with Hor847 and Hor1379. The detected genes differ from the resistance genes of the crossing partners, viz. Ml-al2, Ml-(Ab), Ml-(CP) and Ml-(1402). The accessions from China (Hor824 and Hor4021) each possess two resistance genes which differ from Ml-a12, Ml-(La) and Ml-(CP). The major gene is common to both accessions and is either identical, allelic or closely linked to a gene in the variety Nigrate. The Columbian accession Hor1894 possesses one resistance gene linked to a resistance gene in Nigrate but this gene differs from the Ml-a locus. The variety Palestine (Hor3997) possesses two resistance genes of which one is allelic or closely linked to Ml-(at).     

α-Tomatine and other steroidal glycoalkaloids in fruits of tomato lines resistant to the glasshouse whitefly (Trialeurodes vaporariorum Westw.)

Summary The total steroidal alkaloid compositions of the mature-harvested fruits of the tomato cultivar Allround (Lycopersicon esculentum), of the species L. hirsutum glabratum, resistant to the glasshouse whitefly (Trialeurodes vaporariorum), and of four resistant lines were determined by capillary gas chromatography. The contents of -tomatine in the red-ripe fruits of Allround and in those of the lines were low (5 mg/kg fresh weight). The green-mature fruits of the wild species had a high content (3390 mg/kg fresh weight) of -tomatine. The total alkaloid profiles of Allround and of the lines were similar. Comparison of flame ionisation detector response with thermoionic detector response indicated that in addition to tomatidine, the aglycone of -tomatine, a small amount of one other steroidal alkaloid might be present in Allround and in the lines. The wild species contained five compounds which possibly are steroidal alkaloids.The safety level of -tomatine in tomatoes is discussed. It was concluded that, in respect of the glycoalkaloids of the mature-harvested fruits, the resistant tomato breeding lines are as safe for human cosumption as the standard cultivar.     

Genetic and cytogenetic studies with a male sterile mutant of common wheat (Triticum aestivum)

Summary Genetic and cytogenetic studies were done on a male sterile mutant of the wheat variety Probus. Association of the 4A chromosome carrying the ms gene was studied in the F₁ of the male sterile Probus with Chinese Spring ditelo 4AS, with Transec and with line T4AS-DRS respectively. The presumption that the genetic male sterility of the mutant was due to a terminal deletion of the short arm of chromosome 4A could be confirmed.Linkage studies showed that the ms gene was at 17 map units from the dwarfing gene (Rht3) of Minister dwarf. This allows selection of short male sterile plants at the seedling stage.     

Molecular and biological studies on male sterile cytoplasm in Cruciferae. II. The origin of Ogura male sterile cytoplasm inferred from the segregation pattern of male sterility in the F1 progeny of wild and cultivated radishes (Raphanus sativus L.)

Summary To determine the origin of Ogura male sterile cytoplasm in radish (Raphanus sativus L.), wild and cultivated radishes were crossed. Three types of progeny resulted from the F₁ hybrids between the wild radish from Kushikino with Ogura-type mtDNA and the cultivars (Uchiki-Gensuke or Comet). The segregation patterns of the male sterility were compared with those of Ogura cytoplasm. The male sterility induced in the F₁ hybrid was maintained by crossing with Uchiki-Gensuke, that maintains Ogura male sterility. In the two types of progeny, in which Comet (a restorer of Ogura cytoplasm) was used as one of the parents, both fertile and sterile plants segregated at the predicted ratio on the assumption that a single dominant fertility restoring gene exists in the restorer. From these results, we concluded that the Ogura cytoplasm is identical to that of the wild radish, and the former originated in a population of Japanese wild radish.     

Inheritance studies of characters associated with floating habit and their linkage relationship in rice

Summary Deep water rice varieties in general have certain peculiar characters which are associated with floating habit. These characters are (i) early nodal differentiation, (ii) nodal rooting, (iii) spreading habit, (iv) awned grains, (v) brown hull colour, (vi) red pericarp (red rice), and (vii) seed dormancy. Inheritance of these characters and linkage relationship of genes governing these characters were studied in a cross between Pankaj (non floating) and Nageribao (floating) rice varieties. Nageribao, a cultivar from Assam possesses these characters.Early nodal differentiation was observed to be controlled by a single dominant gene, designated as Nd. Nodal rooting was controlled by two dominant complementary genes, designated as Nr ₁ and Nr ₂. We found an inhibitory factor for spreading habit and one for brown hull colour in Pankaj; the operation of two dominant duplicate genes An ₁ and An ₂ for controlling awning characters, a single dominant gene Rd for red pericarp colour and a single dominant gene Gd for grain dormancy. Joint segregations between these characters resulted in the assignment of genes in the X linkage group of indica rices with estimated map distances based on the cross-over values. The genes An (awning), Es (spreading habit), Nr (nodal rooting) and Nd (nodal differentiation) were observed to be associated with each other. The gene for red pericarp (Rd) was observed to be linked with the grain dormaney gene Gd.     

Resistance to the glasshouse whitefly (Trialeurodes vaporariorum Westw.) in sweet pepper (Capsicum annuum L.)

Summary Fourteen cultivars, one F₁-hybrid and one half-wild type (Cind) of sweet pepper were tested on resistance to glasshouse whitefly. Several mutually significant levels of resistance were found. Most resistant appeared to be California Wonder, Severka M, Korál and Yolo Wonder. During the test sweet pepper plants were infested both with whiteflies and their parasite — Encarsia formosa, which caused the blackening of whitefly puparia. The blackened puparia are easily seen, enabling an easier and more rapid evaluation of the number of puparia present.     

Partial self-compatibility in ‘Tombul’ and ‘Montebello’ hazelnuts

Summary Self-pollination of hazelnut (Corylus avellana L.) cultivars in 1988 and 1990 revealed the existence of partial self-compatibility in Tombul and Montebello. Percent cluster set in these cultivars averaged 44 and 20%, respectively, but was less than 10% in 8 other cultivars investigated. Percent cluster set from pollination with Segorbe averaged 62 and 41% in 1988 and 1990, respectively. Self-pollination produced 40% fewer nuts per cluster and twice as many blanks as cross-pollination. All cultivars and selections have an active sporophytic incompatibility system.Evaluation of self-compatibility in seedlings from the cross Montebello × Compton revealed that the partial self-compatibility of the maternal parent was transmitted to some of the progeny. Self-pollination resulted in greater than 10% cluster set in two selections, OSU 41.134 and OSU 43.025, in both years, but only in 1988 in OSU 42.089 and Willamette. Three other selections had very low set in both years. Results of incompatible crosses with standard testers were generally in agreement with those of self-pollination, except that the S₂ tester induced greater set on 3 genotypes in 1988 and the S1 tester on 2 genotypes in 1990 than self-pollination. The partial self-compatibility of Montebello, OSU 41.134, and OSU 43.025 appears to be due to a failure of their stigmas to prohibit pollen tube growth in incompatible crosses. There is no evidence of a pollen-part mutation in Montebello, nor is there evidence that partial self-compatibility is due to the interaction of S-alleles, as Barcelona, which has the same alleles as these three genotypes, failed to set nuts in all incompatible crosses.     

Chromosomal location of genes controlling 6-phosphogluconate dehydrogenase,glucose-6-phosphate dehydrogenase and glutamate dehydrogenase isozymes in cultivated rye

Summary The 6-phosphogluconate dehydrogenase (6-PGD), glucose-6-phosphate dehydrogenase (G-6-PD) and glutamate dehydrogenase (GDH) zymogram phenotypes of wheat, rye and their aneuploid derivates were determined. At least three genes involved in the production of 6-PGD isozymes were located on chromosome arms 4RL, 6RL and 2RL of Imperial rye, King II rye and Dakold rye. Evidence was obtained that at least one gene located on chromosome arm 5RS controls G-6-PD isozyme activities in these varieties of rye and one gene involved in the production of GDH isozymes was located on chromosome arm 2RS of Imperial, King II and Dakold rye. The results indicate that the 6-PGD isozymes exist as dimers and monomers. No possible structure of the G-6-PD and GDH could be determined.     

A comparative study on anther development in male-fertile and male-sterile plants of Pelargonium crispumL'Her. ex Ait.

Summary Anther development of male-fertile and male-sterile plants in Pelargonium crispum was anatomically examined. Three cultivars, i.e., Lemon crispum, Crispum minor and Prince Rupert, were used. Lemon crispum and Crispum minor are male-fertile, whereas Prince Rupert is male-sterile. The tapetum in every cultivar examined behaved like an amoeba. The tapetal cells of the anther form plasmodial masses. Then, the plasmodial masses fuse producing a periplasmodium. The periplasmodium degenerates and finally disappears. There are no differences in tapetal behaviour between fertile and sterile anthers. In the sterile anthers the endothecium and lip cells do not develop sufficiently. Young microspores show normal growth at early stages. After the completion of their cell wall formation, however, the microspores in the sterile anthers lose their cytoplasm and become empty. On the other hand, the microspores in the fertile anthers increase the volume of their cytoplasm and become fertile pollen grains.     

Effect of in vitro propagation methods on field performance of two strawberry cultivars

Summary Strawberry cultivars, Redcoat and Veestar, propagated by meristem culture (MC), callus culture (CC) and direct shoot regeneration (DR) from leaf disks were compared for their vegetative and reproductive characters with standard runner (SR) propagated plants under field conditions. In the planting year, in vitro propagated plants of both cultivars had the same number of leaves as SR plants, but in vitro propagated Redcoat produced fewer stolons per plant than SR plants. However, in the following year, in vitro propagated mother plants of both cultivars had more leaves and higher runner production than SR mother plants. Flowering and fruiting behaviour of Veestar was not appreciably influenced by in vitro propagation methods. However, in vitro propagated plants of Redcoat flowered earlier and produced more flowers and fruits than SR plants, but still maintained normal berry weight. Among in vitro propagated plants, DR plants of Redcoat were the earliest to flower, whereas MC plants produced more flowers and fruits. The field performance of the first daughter plants derived from the in vitro propagated plants was consistent with their respective mother plants. Leaf shape of both cultivars was not altered by in vitro propagation. Phenotypic abnormalities were mainly confined to occurrence of yellow leaf variants in MC and CC plants and occasional appearance of plants with irregular flowering and growth habit among CC plants.NRCC No. 38004     

In vitro propagation of Japanese garden iris,Iris ensata Thunb.

Summary Explants of young scapes of Iris ensata were cultured on MS medium with 1 mg/l NAA, 1 mg/l 6-BA, 30 g/l sucrose and 10 g/l agar, and this species was characterized by high variety specificity for callus, shoot and root induction. Among 23 varieties and one wild form tested, Okichidori, Miyukisudare and Meiji-l exhibited a considerable rate of shoot induction, although these induced poorly rooted shoots. In addition, two types of callus induction such as green and white calli were observed, and the induction of green-type calli was significantly correlated with that of shoots. Surprisingly, the only modification, half-strength MS inorganic salts, for the above medium proved to be very effective for shoot induction in the scape culture. For shoots obtained from the scape culture, effects of sucrose concentrations and activated charcoal on root induction were examined by using 1/2 MS with 1 mg/l NAA, 1 mg/l 6-BA, 30 g/l sucrose and 10 g/l agar as the basic medium. The addition of 1% activated charcoal to the media had a marked effect for root induction independent of sucrose concentrations and varieties tested. The in vitro propagation technique of I. ensata is discussed.     

Stability of forage yield and quality in pearl millet hybrids heterogenous for rust resistance

Summary The susceptible pearl millet hybrid Tifleaf 1, the resistant hybrid Tifleaf 2, and two experimental 3-way hybrids with different proportions of resistant and susceptible plants were evaluated for rust resistance and forage yield and quality in 1990, 1991, and 1992. Different environmental conditions were obtained by varying planting date, planting density, and fungicide applications across three years of evaluation in the field. Rust severity of forage was negatively correlated with late season green yield, dry matter yield, in vitro dry matter digestibility, and digestible dry matter yield. The stability across environments of the 3-way hybrids was intermediate between resistant Tifleaf 2 and susceptible Tifleaf 1 for rust severity and the yield and quality measurements negatively correlated with rust severity. Mixtures of resistant and susceptible plants would probably provide greater control of rust than measured in these small-plot experiments. Although a mixture of resistant and susceptible plants appears to provide an alternative to monogenic control of rust in forage pearl millets, identification and utilization of additional sources of resistance would be beneficial to improve the performance of 3-way hybrids.     

Accumulating polygenes for partial resistance in barley to barley leaf rust,Puccinia hordei. I. Selection for increased latent periods

Summary The barley cultivar Cebaba Capa was crossed to the cultivar L94, which is assumed to carry no genes for increased latent periods, and Vada, which is assumed to carry five to six minor genes for a longer latent period (LP). In the F2 selection was carried out for short and long LP's in the young flag leaves to Puccinia hordei in both crosses. In the F3, F4 and F5 the selection for short as well as for long LP continued by selecting the extreme plants in the extreme lines, a typical pedigree selection approach.The LP's are given relative to those of L94, set at 100 and of Vada, set at 185. From the cross with L94 homogeneous lines were obtained with relative LP's of 100 and of 220. From the cross with Vada the extreme lines had LP's of 135 and around or even beyond 300.Cebaba Capa is thought to carry four to six minor genes with an average gene effect slightly larger than those of the five to six minor genes in Vada. From the four to six minor genes one or two may be identical to or closely linked with minor genes of Vada, the others appeared to be different. In the lines with LP's of close to 300 or even more the number of minor genes accumulated is thought to be in the order of eight or nine. These gene number estimates are based on independent assortment. If linkage occurs the number of genes involved may be larger.Because of the high correlation between LP in the young flag leaf and the partial resistance in the field the selected lines are assumed to have a partial resistance to barley leaf rust far beyond that of Vada, which represents almost the highest level of partial resistance in European cultivars.     

Breeding for resistance to yellow disease of hyacinths. II. Influence of flowering time,leaf characters,stomata and chromosome number on the degree of resistance

Summary Analysis of an incomplete diallel design with 14 hyacinth cultivars and 4 wild accessions of Hyacinthus orientalis showed a significant GCA component for resistance to yellow disease. The late flowering hyacinth cultivars King of the Blues and Marconi and the early flowering Hyacinthus orientalis 70129 were found to be the best combiners for yellow disease resistance. Within a cultivar, the degree of earliness itself was not associated with the degree of resistance. Correlation coefficients of leaf characters and degree of resistance showed that hyacinths with short and/or narrow leaves are generally more resistant than those with long and/or broad leaves. Tetraploid cultivars with few, large stomata tend to be susceptible, diploid ones with many small stomata tend to be the more resistant.     

Inheritance of firmness in raw cucumber (Cucumis sativus L.) fruit

Summary Inheritance of raw cucumber fruit texture (Magness-Taylor Fruit Pressure Tester firmness) was investigated over a 4-year period from 1971–1974. Results from 2 separate but related experiments suggested that firmness was quantitatively inherited with sufficient additive effects to permit gain from selection. In a selection study within 4 F₂ populations derived from crosses between firm (Chipper and Gy3) and soft (Mincu and Green F) fruit type cultivars, variation among and within F₃ and F₄ families was significant but overall family means were not significantly higher than the high parent in any of the 4 crosses. Narrow sense heritability estimates for fruit texture were 0.80 in the Mincu × Chipper population and 0.77 in the Green F × Chipper, Mincu × Gy3, and Gy3 × Green F crosses. In a separate experiment, generation means analysis was used to assess the mode of gene action in 2 crosses: Green F × Chipper, and Gy3 × Green F. Additive genetic effects accounted for 98.8% and 99.3% of the total genetic variation within each cross, respectively.Scientific Journal Series Paper No. 9794.     

Pleiotropic association of infection frequency and latent period of two barley cultivars partially resistant to barley leaf rust

Summary Cebada Capa, carrying four to six minor genes for a longer latent period (LP), was crossed to L94 and Vada, carrying no and five to six minor genes for a longer LP respectively. Of each of 68 F3-lines the infection frequency (IF) and the LP of ten just-heading plants were assessed. There appeared to be a strong association between IF and LP, whereby the relationship between IF and LP of both crosses could be described by a single linear regression equation. The data strongly suggest that the genes for increased LP pleiotropically decrease the IF. The possibility of a close linkage between genes for reduced IF and genes for increased LP, although unlikely, could not be excluded.     

Genetics of resistance to five strains of turnip mosaic virus in Chinese cabbage

Summary Inheritance of resistance to turnip mosaic virus (TuMV) strains C1, C2, C3, C4, and C5 in Chinese cabbage (Brassica campestris subsp. pekinensis) was evaluated using monoclonal antibodies. Crosses were made between a resistant line, 0–2, and four susceptible line. Seoul (SE),SSD31 (SS), Cheongbang (CH), and Yaki 1 ho (YA), to determine the inheritance of resistance of 0–2 in different genetic backgrounds. Resistance to TuMV was controlled by a single dominant gene or double dominant genes depending on the strain and cross. The resistance genes of 0–2 were modified by susceptible parents such that a single dominant gene was involved in the SS×0–2 combination, but double dominant genes in the SE×0–2 against TuMV-C3 or TuMV-C5. ELISA tests using inoculated and noninoculated leaves in the same plant suggested that the dominant resistance genes inhibit virus movement rather than virus multiplication.     

Resistance to Corynebacterium michiganense in tomato genotypes

Summary The highest level of resistance to Corynebacterium michiganense was found in Irat L3 and Okitsu Sozai 1–20. Resistance was partial and symptomless plants proved to be carriers of the disease. The resistance is at least partially based on a diminished multiplication of the pathogen in the host plant.     

Evaluating drought resistance in germplasm of meadow fescue

Summary The drought resistance of 25 accessions of meadow fescue (Festuca pratensis Huds.) from seven countries was investigated in four experiments: two in the glasshouse using pot-grown plants from which water was withheld for various periods, and two in controlled environments under osmotic stress.There were significant differences between populations (broad-sense heritabilities or repeatabilities) in all four experiments. In the glasshouse there was a large residual effect of yield potential on production during and after slight-to-moderate drought, and different susceptibilities appeared only after very severe drought. The most consistently high-yielding accessions were from the Bergamo alps in Italy. Recovery after drought was strongly correlated with tiller survival. Continued production under moderate drought was considered important in wetter climates, whereas survival and recovery under severe drought was often associated with low production or flowering in the seeding year, and more typical of summer-drought climates.Leaf growth rates of plants subjected to zero or moderate osmotic stress were correlated with yields of irrigated or moderately-stressed plants in the glasshouse, although there was no differential susceptibility to mild stress. Under severe osmotic stress there were very large differences in survival between populations, but there was no relationship with survival under glasshouse conditions.The inconsistency of population rankings across experiments shows that no one technique gives a full evaluation of drought resistance, and emphasizes the complex nature of the phenomenon. It was possible, however, to identify (a) regions meriting further collections, and (b) ecotypes that had desirable responses in all experiments and could contribute to variety improvement.