Correlations among some statistical measures of phenotypic stability

Summary Two basic concepts of phenotypic stability are distinguished: (i) a stable genotype should have a minimal variance under different environmental conditions (biological concept), or (ii) a stable genotype should show minimal interactions with environments as measured by the ecovalence (agronomic concept). In a study using field trial data of various crops it is shown that the widely used method of regressing the yield of a given genotype in the various environments on the respective means of all genotypes under test may be regarded as a combination of these two concepts, for coefficients of regression are almost perfectly correlated with variances, and mean squares for deviations from regression are almost perfectly correlated with ecovalences.     

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.     

Effects of nucleus,cytoplasm and male sterile nucleus-cytoplasm combinations on callus initiation in anther culture of wheat

Summary Nuclear and cytoplasmic factors affect tissue culture response in wheat (Triticum aestivum), and cytoplasmic male sterility may enhance callus initiation in anther culture. Three wheat nuclear genotypes, each in normal and two alien cytoplasms conferring cytoplasmic male sterility, were evaluated for callus initiation frequency in anther culture. Nuclear genotype had the greatest effect on callus initiation, but cytoplasm and nucleus X cytoplasm interaction also produced significant effects. The nuclear genotype of Chris outperformed Butte and Coteau in all cytoplasms. Ordinary wheat and Triticum timopheevi cytoplasms outperformed Aegilops speltoides cytoplasm. Cytoplasmic male sterility did not increase callus initiation. This suggests manipulating the nuclear genotype is the best strategy for improving the capacity of wheat to initiate callus in anther culture.     

Comparative studies within and between seed and seedling populations of leafed, ‘leafless’ and ‘semi-leafles’ genotypes of Pisum sativum L.

In an attempt to explain previously observed differences between the growth rates of leafless and conventional plants, we have compared representatives of three pea phenotypes; conventional (AfAfStSt), semileafless (afafStSt) and leafless (afafstst) with regard to their embryonic axis/embryo weight ratio and their patterns of pre-emergent growth. Within each phenotype, comparisons were made between genotypes which differed for mean weight per seed and between seed weight classes within each genotype. Although significant differences were found between genotypes for embryonic axis/embryo weight ratios, these could not be attributed to differences between phenotypes. Within each seed population there was a consistent decrease in this weight ratio with increasing seed size irrespective of phenotype.Relative growth rate (RGR) of the seedlings prior to emergence was similar for all genotypes within and between phenotypes and also for seed size classes from individual populations. There was however a positive relationship betweed seed size and absolute growth rate within and between seed populations.The results suggest that differences between the phenotypes do not become manifest until after emergence of the seedling from the soil and the possibility of a post-emergent lag phase in the leafless type is therefore suggested.     

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.     

The influence of genotype and environment on seed and embryo development in barley (Hordeum vulgare L.) after crossing with Hordeum bulbosum L.

Summary Seed and embryo development was studied in crosses between H. bulbosum and the barley genotypes VK 16032, Vada and Vogelsanger Gold and subsequently the F₁ and F₂ progenies from VK 16032 x Vada and VK 16032 x Vogelsanger Gold. Both seed and embryo development are strongly influenced by the barley genotype. Favourable environmental conditions can promote seed and embryo development in genotypes with existing good characters. Dominant inheritance for good seed development and incomplete dominance for large embryos is evident. Linkage between small embryo size and winter habit exists in Vogelsanger Gold.     

Male-sterility in nigerian bulrush millets (Pennisetum americanum (L.) K. Schum)

Summary The occurrence of three male-sterile plants is reported. One in a population of ex-Bormu, an improved recommended variety of day-length neutral gero bulrush millet and the two others in the selfed progeny of a population of maiwa bulrush millet, a short-day photoperiod-sensitive type. Tests confirmed the cytoplasmic-genic nature of the male-sterility in the gero population. No tests could be conducted for maiwa.The transfer of male-sterility from the male-sterile Tift 23A bulrush millet, obtained from the United States, into a maiwa population is also reported. After six backcrosses the maiwa genotype appeared to have been reconstituted against the background of a male-sterility inducing cytoplasm. Maiwa male-sterility maintainer plants have also been identified.     

Karyotypes and chromosome association in aneuploid varieties of Japanese garden iris,Iris ensata Thunb

Summary Karyotypes, chromosome association and pollen fertility of aneuploid varieties (2n=25), Ochibagoromo, Matsusakatsukasa and Isehomare in Iris ensata were analysed and compared with those of eu-diploid varieties (2n=24), Shishinden, Kachô and Asahimaru. The somatic chromosome complement of the aneuploid varieties consisted of 11 pairs and 3 singles of chromosomes and that of the eu-diploid varieties 12 pairs of chromosomes. The singles of chromosomes in the aneuploid varieties had similarity with one another and with a pair of chromosomes in the eu-diploid varieties. The high frequency of normal association was present in the eu-diploid varieties, and this indicated that 12 pairs of chromosomes had full homology between each other. In contrast, the mean chromosome association per cell in an aneuploid variety Ochibagoromo was 4.615_I+10.067_II+0.077_III+0.005_IV, indicating that the chromosome complement of this variety consisted of 11 pairs and 3 singles and that these singles had partial homology among them. The eu-diploid varieties exhibited high pollen fertility due to their regularity of chromosome association; the aneuploid varieties considerably lower fertility, i.e. 28.2% for Ochibagoromo, 31.8% for Isehomare and 43.8% for Matsusakatsukasa. The primary cause for the low fertility of these varieties seemes to be the partial homology among 3 single chromosomes. Finally, the origin and the development of the aneuploid varieties were discussed.     

A quantitative classification method for assessing resistance to Phytophthora fragariae var. fragariae in strawberry

Summary Race specific resistance to red core (red stele) root rot, caused by Phytophthora fragariae var. fragariae, is known to occur in the cultivated strawberry (Fragaria × ananassa Duch.), but frequently this resistance does not completely prevent infection. We therefore developed a classification method which distinguishes partial and complete resistance. It accounts for differences in the aggressiveness of isolates and in the appropriateness of experimental conditions for infection. This method is based on the microscopically assessed disease severity of a tested strawberry genotype relative to that of an universally susceptible reference cultivar. If the tested genotype is significantly (P0.01) less diseased, it is considered to possess resistance. Data from 18 genotype-isolate combinations, including five genotypes (Blakemore, Md683, Redgauntlet, Del Norte, Yaquina A) and four North American isolates (A2, A4, A6 and A10) demonstrated the validity of our classification scheme.Abbreviations PIRT Percentage of Invaded Root Tissue     

Genotype × environment interaction in carbon isotope discrimination and seed yield in cowpea (Vigna unguiculata L. Walp.)

Summary Twenty locally-adapted but genetically diverse cowpea genotypes were grown in 17 replicated trials in a range of sites and seasons in the drylands of eastern Kenya, and the discrimination against the heavy isotope of carbon (with a mass of 13) () was determined in grain and straw samples. Most genotypes gave similar, low grain yields in the environments which subjected the plants to drought stress, but high yielding and low yielding genotypes were clearly distinct in the less stressful environments. The converse pattern was found for : the genotypes were all very similar in the non-stressful (high-) environments, but in the stressful environments, low- (drought susceptible) and high- (drought avoiding) genotypes were clearly distinct. This pattern was clearest for straw , but was also apparent for grain . The early-maturing genotypes, which escaped terminal drought, were generally those with the most stable and highest , but in the case of straw there were statistically significant deviations from this relationship. It is concluded that provides a reliable measure of the specific response of cowpea genotypes to drought, which may be of value in breeding programs provided that carbon isotope discrimination can be measured reasonably economically.     

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.     

Morphology,cytology and forage potential of Pennisetum americanum (L.) K. Schum. x P. Purpureum Schum. amphidiploids

Summary F₁ hybrids between short-day photoperiod- sensitive maiwa bulrush millet, Pennisetum americanum (2n=14), and elephant grass, P. purpureum (2n=28), are triploid (2n=21), sterile, and can only be propagated vegetatively. Fertile amphidiploids, (2n=42, with 21 bivalents) were produced by colchicine treatment. Good seed set was obtained upon selfing the amphidiploids and the progeny exhibited variable pollen fertility and bivalent univalent and multivalent formation.Reciprocal crosses between elephant grass and the colchicine-induced amphidiploid failed to produce seeds. The maiwa millet x amphidiploid cross resulted in poor seed set and the reciprocal failed. Maiwa x amphidiploid hybrids were pollen sterile with 2n=21, rather than the expected 2n=28, indicating chromosome elimination.Morphologically, the amphidiploids and maiwa x amphidiploid hybrids closely resembled elephant grass and the F₁ hybrid. The amphidiploids showed no superiority over the F₁ hybrid and elephant grass in either forage yield or quality but one maiwa x amphidiploid genotype surpassed a promising local elephant grass selection in forage dry matter yield and flowered for a relatively short period.     

Low light intensity and flower bud abortion in Asiatic hybrid lilies. I. Genetic variation among cultivars and progenies of a diallel cross

Summary When Asiatic lilies are forced during the winter period, additional light is needed to prevent flower bud abscission and flower bud blasting. Growth room experiments showed considerable differences among eight lily cultivars in their response to low light. Among these cultivars, Connecticut King and Enchantment appeared to be the most sensitive to low light conditions while Uncle Sam and Scout were the least sensitive.Analysis of an incomplete diallel cross between nine cultivars showed significant differences in general combining ability (GCA) for flower bud abortion, number of buds, forcing time, plant height and leaf scorch under winter greenhouse conditions. Enchantment had the highest positive GCA for bud abortion, indicating a high sensitivity to low light conditions. Uncle Sam had the lowest GCA. Pirate and Scout appeared to have a high GCA for sensitivity to leaf scorch. Connecticut King was found to be a probable source of cytoplasmic male sterility. The data suggest that male sterility is associated with better response to low light conditions.     

Development of a triticale resistant to the greenbug: An historical perspective

Summary A greenbug [Schizaphis graminum (Rondani)] resistant strain of rye (Secale cereale L.) Insave F.A. from Argentina was crossed with Chinese Spring wheat (Triticum aestivum L.) and also with Elbon and Balbo cultivars of common rye. Juvenile plants of the primary wheat X rye hybrid were treated with colchicine. Partially fertile amphidiploids were obtained that are resistant to greenbug Biotypes B and C. F₁ and F₂ populations of seedling plants derived from crosses of Insave F.A. with Elbon and Balbo rye were tested for reaction to the greenbug to determine the genetic basis of inheritance. The results confirmed previous reports that resistance in Insave F.A. is conditioned by a single dominant gene.Deceased     

Study of the parentage of grape cultivars by genetic interpretation of GPI-2 and PGM-2 isozymes

Summary Two highly variable enzyme systems of glucosephosphate isomerase (GPI) and phosphoglucomutase (PGM) were used to investigate the parentages of grape cultivars. Of 35 parent/offspring combinations that we investigated, 30 combinations gave alleles in the offspring which were presented in the reported parents, whereas 5 combinations gave alleles in the offspring which were not extractable from the reported parents. The Gpi-2 genotype of Hiro Hamburg and the Pgm-2 genotype of Pione indicated that Koshu Sanjaku and Cannon Hall Muscat may not have been the paternal parent respectively. The Gpi-2 genotype of New Niagara and the Gpi-2 and Pgm-2 genotypes of Beniyamabiko indicated that Niagara and a hybrid from DxK151 x Delaware may not have been the maternal parent respectively. The Gpi-2 genotype of Cannon Hall Muscat grown in Japan indicated that this cultivar may not have originated as a tetraploid sport of Muscat of Alexandria.     

A new tomato rootstock seed parent

A new tomato rootstock seed parent which combines the characters green stem, potato leaf and long style in a Lycopersicon esculentum genotype has been produced. This will facilitate seed production of the interspecific F₁ hybrid rootstock which is used for grafted crops, and also permit the positive identification of any off-types which arise from accidental self-pollination of the seed parent. The new seed parent has been named GCR 66. It is proposed that rootstocks derived from this type of seed parent shall be called Markerstocks. GCR 66 is very similar to the cultivar Ailsa Craig in its agronomic characters and will be useful for studies with the tomato when pollination needs to be accurately controlled.     

Vaktijdschriften op het gebied van de plantenveredeling

Summary The English abstracting journal Plant Breeding Abstracts gives a satisfactory synopsis of books on plant breeding and of articles in this field that have appeared in general and professional journals.In the above survey are mentioned the following periodicals: Sveriges Utsädesföreningstidskrift (1891 ), Zeitschrift für Pflanzenzüchtung (1913 ), Der Züchter (1929 ), Agri Hortique Genetica (1943 ), Indian Journal of Genetics and Plant Breeding (1941 ), Melhoramento (1948 ), Annales de l'Amélioration (1951 ) and Euphytica, Netherlands Journal of Plant Breeding (1952 ).

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Vaktijdschriften op het gebied van de plantenveredeling

     

The inheritance and association of resistance to rust,common bacterial blight,plant habit and foliar abnormalities in Phaseolus vulgaris L.

Summary No antagonistic or synergistic interaction was found between isolates of Uromyces appendiculatus var. appendiculatus and Xanthomonas campestris pv. phaseoli when inoculated to the same plant. A single dominant gene was suggested to control resistance to three isolates of rust in the crosses Pompadour Checa × Chichara and Pompadour Checa × NE W-4. A two-gene model was confirmed for the reaction to the three rust isolates for the crosses Pompadour Checa × GN Tara and Pompadour Checa × San Cristobal; a dominant (Ur _p) gene determined resistance and was epistastic to a dominant gene (Ur _t) for susceptibility. (Ur _t) was expressed only in the presence of recessive (ur _p) alleles. The reaction to common bacterial blight was quantitatively inherited and an association was detected with plant habit but not with rust reaction and leaf variegation. Plants with leaf variegation and crippled growth, were detected in the progeny of the cross Pompadour Checa × GN Tara and were controlled by duplicate recessive genes (mutatorunstable genes) and three genes, acting additively, respectively. The developmental expression of the latter trait varied considerably. Linkage was detected between genes controlling the variegated and the crippling traits.Published as Paper No. 7839, Journal Series, Nebraska Agricultural Experiment Station. Research was conducted under project No. 20-036.     

Linkage studies in rice (Oryza sativa L.): Flowering,growth habit and pigmentation

Summary Genetic analysis of ten characters in a rice cross M 18 × T979 revealed the interaction of duplicate, complimentary, inhibitory and anti-inhibitory genes in conditioning pigment in eight characters and in determining flowering and growth habit. The action of genes and their interactions indicated by complex ratios for all the ten characters are claimed to be the first reports. pleiotropic action of two complementary genes and four duplicate genes has been detected. Two linkage groups, one with three genes (Ai-Plg-Ai-Pau-Pja) and the other with nine genes (Plg_a-Pin_a-Er_a-Ef_a-I-Plg-Pg₁-Pn₁-Pr₁-Pnr₁) have been constituted. The three-gene group is tentatively placed in the IV mp group and the other with nine genes is assigned to the X fh group. As a result of the present investigation Ai-Plg is an addition to the IV mp group and Plg_a, Pin_a, Er_a, I-Plg, Pg₁, Pn₁ Pr₁ and Pnr₁ are contributions to the X fh group.     

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.