High Parent Research Articles

Selection For Flag Leaf Stomatal Frequency In Bread Wheat

AbstractTwo Cultivars Of Bread Wheat (Triticum Aestivum L.) Showing Significant Differences In Stomatal Frequency On The Adaxial Surface Of The Flag Leaf Blade, Were Hybridized. Transgressive Segregation For Stomatal Frequency Was Observed In The F2 Generation and Selections Were Made For High and Low Stomatal Frequency. In The F9 Generation Two Selections Had Significantly Higher Frequencies Than The Higher Parent. Heritability For Stomatal Frequency Based On Parent‐Progeny Regression Were 42 % (F3—F4) and 81 % (F4—F5). Stomatal Frequency Was Negatively Correlated With The Flag Leaf Blade Area, Mesophyll Cell Size and Grain Size, However, Exceptions Were Observed.

Analysis of the yield potential and yield components of F1 and F2 hybrids of crosses between wheat (Triticum aestivum L.) and spelt (Triticum spelta L.)

F1 and F2 hybrids were produced using three winter wheat varieties (Bernina = biscuit wheat, Arina and Forno = bread wheat) and two spelt cultivars (Oberkulmer and Rouquin). Data are based on field trials in 1989 and 1990. All the combinations tested gave a very high relative heterosis on grain yield per ear, varying between 29.9% and 47.6% with an average of 42.1%. Even the higher parent was outyielded by 24.1% to 45.7%. This was the result of a heterosis effect on the two yield parameters grain number per ear and single grain weight. In the F2, heterosis for grain yield per ear was not significant with a range between 3.9% and 12.0%. F1 hybrids showed a heterosis effect on plant height but no hybrid was taller than the spelt parents. These data show that the gene pool of spelt could be potentially usefull for the selection of parents for hybrid production. For practical applications there remain several problems to be solved. Despite the very high heterosis effect the yield potential of spelt needs to be improved. No short spelt varieties exist at present to produce hybrids short enough for commercial application. Technical problems in the seed production arise because of the close tightness of the spelt glumes hampering either the pollination by the wheat parent or the pollen dispersal if used as a pollinator. However, a breeding effort to select for improved parents within the gene pool of spelt appears useful for future F1 hybrids between spelt and wheat.

Parenting satisfaction of mothers during midlife

The present investigation explores the relations among midlife identity concerns, marital satisfaction, mental health, and parenting satisfaction among mothers of preadolescents and early adolescents. Data were obtained from 129 intact families with a firstborn child between the ages of 10 and 15. The results suggest that intense midlife concerns are associated with diminished satisfaction with parenting, although this relation is moderated by the mother's reported marital satisfaction and her overall psychological wellbeing. Specifically, mothers with intense midlife crisis symptoms report higher parenting satisfaction when their marital satisfaction is high, but lower parental satisfaction when their midlife concerns are accompanied by psychological distress. The relations among midlife concerns, marital satisfaction, psychological symptoms, and mothers' satisfaction with parenting are not moderated by the sex of the adolescent.

SELECTION FOR YIELD, KERNEL WEIGHT AND PROTEIN CONTENT IN EARLY GENERATIONS OF SIX WHEAT CROSSES

Early generation data consisting of F1 heterosis, F1, F2 and F3 mean performances, parent-offspring regression, and F2–F3 intergeneration correlation were used to identify potentially promising spring wheat (Triticum aestivum L. em Thell) crosses in terms of yield, kernel weight and protein content. The F1 test identified one high-yielding cross out of six showing significant level of higher parent (38%) and mid-parent (70%) heterosis for yield, respectively. The top yielding cross, viz. Glenlea × NB505, in F1 was also the second highest yielding population in F2 and the best yielder in F3 based on two locations. Hence, although F2 single plant productivity measurements misplaced the rankings of some of the crosses, F1 and F3 performances indicated the relative potential of the different populations. Most crosses showed nonsignificant F2–F3 regression and correlation coefficients for yield but significant coefficients for kernel weight. For protein content highly significant F2–F3 regression and correlation coefficients were observed only for crosses involving the high protein parent. The use in F1 of weight-free selection indices involving yield, kernel weight and protein content ranked Glenlea × NB505 as the best of six populations whereas in F3 the same cross had the best aggregate merit when only yield and kernel weight were considered in the index. The inclusion of protein content in the index favored a high protein cross, Sinton × Glenlea.Key words: Wheat, Triticum aestivum, heterosis, parent-offspring regression, intergeneration correlation, selection index

Parent-child communication as a function of parental education, sex of parent and child and situational factors

Parent-child communication was studied in different contexts (home vs laboratory, variation between and within the tasks, dyad vs triad). The subjects were 48 Finnish families with a four-year-old child. The families were divided into euqual groups of lower and higher parental education. The experiments were carried out in two stages: the first in the laboratory setting and the second in the laboratory setting or at home. The videotaped situations consisted of different cooperative tasks. The first result based on global ratings of dyads and triads (initiation/guidance, cooperation, emotionality) and on evaluation of parents’ teaching styles showed only minor differences in interactional measures, whereas the higher education parents used more mentally demanding teaching styles than the lower education parents. In addition, the particular nature of the tasks and the phase of the task was found to be essential to the forms of interaction.

Selecting for nutritive value in Digitaria milanjiana. 1. Breeding of contrasting full-sib clones differing in leaf digestibility

Nineteen F1 families were produced by pair-crossing 7 stoloniferous genotypes of Digitaria milanjiana. Progenies and parents were grown as spaced plants (0.5 by 0.5 m microswards) and plucked samples were taken from vegetative regrowth in 2 successive seasons for estimation of digestibility using the in vitro cellulase method. Stolon number, herbage yield (one, 9-week regrowth), flowering date and leaf width were also assessed. Parental clones differed significantly in plucked sample digestibility (range 4.1 units) and there was no significant clonexyear interaction. Heritability, based on parent-progeny regression, was 0.86. The occurrence in progenies of a low percentage (4.9%) of genotypes with plucked sample digestibility significantly higher than that of the higher parent suggested that genetic improvement of plucked sample digestibility may be possible. However, such segregates did not occur in the progeny of high digestibility parents. Digestibility of plucked samples was not correlated with any of the agronomic attributes measured. This, together with the high heritability for stolon number (h2 = 0.86) indicates that it is feasible to breed a genotype of D, milanjiana with high yield, high leaf digestibility and vigorous stolon development for clonal propagation. Genotypes with a mean plucked-sample digestibility of >70.0% occurred in 11 families. For these families highest and lowest digestibility genotypes were further sampled; only the top 2 fully expanded leaves were analysed. Conclusions derived from plucked samples were confirmed, showing that full-sibs differed genetically in leaf digestibility. Three pairs of full-sibs, which differed in leaf digestibility by 5.0-7.2 units, were selected for in vivo and physiological comparison.

Diallel analysis for some quantitative characters in Petunia hybrida Hort

Flowering time, plant height and flower size in Petunia hybrida Hort. (multiflora type) have been genetically analysed by means of a 5 × 5 diallel cross. The results indicated that: (1) the three characters are controlled by additive-dominance polygenic systems. The contribution of the additive gene actions to the genetic variance of flowering time was relatively higher than that of dominance. The reverse situation was found for plant height and flower size. (2) Dominance is ambi-directional for the three characters. Ratios of average dominance were in the range of partial for flowering-time, complete for plant height and overdominance for flower size. (3) Number of genes (or gene groups) controlling the characters are about 3, 3 and 5 for flowering time, plant height and flower size: respectively, (4) Heritability estimates are 0.84, 0.88 and 0.89 in the broad-sense and 0.40, 0.49 and 0.37 in the narrow-sense, for flowering time, plant height and flower size; respectively. (5) Heterosis as percent increase of the mean F1-hybrid above the higher parent, or decrease below the lower parent, was observed for flowering time (+ 9.7% to +13.3%), for plant height (-13.6% to -20.3%) and for flower size (+2.5% to +16.0%).

Observed and Predicted Response to Selection for Protein and Yield in Peas1

Few reports of selection for seed yield and seed protein concentration, two important traits in peas, are available in the literature. This study involved the effect of selection for protein in the F2, F3 and F4 and for seed yield in the F3 and F4 generations of four pea (Pisum sativum L.) crosses grown in the field nursery. Mean protein of all progeny in each population was generally lower than the higher parent and tended toward the lower parent. Seed yield/plant values were generally higher than the midparent and tended toward the higher parent. Narrow sense hecitability values estimated through the parentprogeny regression method varied with crosses and generations, and were generally greater for protein (17 to 56%) than for seed yield (0 to 41%).The observed change from selecting for higher % protein ranged from ‒0.84 to 5.85% of the population mean and was generally less than that predicted (2.07 to 5.54%). The observed decrease (‒0.75 to ‒7.05%) in the same trait for negative selection was generally greater than that predicted (‒2.18 to ‒4.62%). The relationship between observed increase in yield from selection (3.22 to 12.53%) and that predicted (0.00 to 19.25%) was variable, but the observed decrease (‒1.93 to ‒17.25%) was generally greater than that predicted 0.00 to ‒17.65%).Correlations between protein and seed yield were small and inconsistent, suggesting that selection for either trait would not necessarily influence the level of the other. Selection for the two traits appears to be effective even in early generations. The amount and rate of progress would be influenced by choice of parents and selection intensity.

The production of F1 hybrid swedes (Brassica napus ssp. Rapifera) by the utilisation of self-incompatability

Six inbred lines from a swede with naturally occurring self-incompatibility were each isolated with a swede cultivar containing marker genes. The percentage of intervarietal hybrids produced by the self-incompatible lines was between 97.4% and 99.6%, whereas in the self-compatible marker cultivar it varied between 7.2% and 26.8%. The F1 hybrids showed increases in dry matter yield of 11.5% to 28.8% over the higher parent.

HYBRID VIGOR AND GENE ACTION IN A SIX-PARENT DIALLEL CROSS OF SOFT WINTER WHEAT

Six soft winter wheat lines were crossed in a diallel fashion and data were obtained from the parents and F1hybrid generation over two years. The mean squares for year by genotype interaction were significant for most measured characters indicating that the genotypes responded somewhat differently each year. The yield response of the F1generation hybrids ranged from −0.7 to 28.1% with 13 of 15 F1hybrids above the higher parent; however, none was significantly higher.Combining ability analyses were performed on the F1hybrids, and mean squares for general combining ability were significant for earliness, plant height, and kernels per spike. No significant mean squares for specific combining ability were detected. Monon was the best general combiner for both number of spikes and yield, and Gaines was a good general combiner for kernels per spike. The Jinks and Hayman (Vr, Wr) graphic analysis indicated that plant height, kernel weight, and number of spikes were controlled by some partial dominance and yield by apparent overdominance.

STUDIES WITH HYBRID WHEAT IN ONTARIO

An F1hybrid from parental wheat (Triticum aestivum L.) cultivars with wide genetic diversity yielded 7329 kg/ha, a 26% increase over the higher yielding parent. Two other crosses resulted in an F1yield increase of 15 and 5%. The best hybrid outyielded Genesee, which averaged 6177 kg/ha, by 19%. All data were averaged over a two-year period and were obtained at a standard seeding rate. Grain yields decreased from the F1to the F2generation in all three crosses and in the best cross from 26 to 13%. Heterosis for grain yield was manifested primarily in tillering and kernels per spike. Tillering increased by 6.9% and kernels per spike by 8.2%, while kernel weight increased by 1.0%, over the higher parent. An increase in plant height was observed. Milling and baking characteristics of F1crosses, made within the soft wheat class, were closer to the softer quality parent. Baking quality declined in the F2generation. Seed produced from two male sterile lines, however, had poorer milling and baking characteristics than seed from their self-fertile counterparts, and this may present a problem for soft quality flour production.

Background factors, extent of sex knowledge and source of information.

To determine extent of sex knowledge and sources of information a survey was conducted among 365 male and 528 female freshman at the University of British Columbia. Only two religious groups were considered in the analysis (77% Protestant 12% Catholic). Regardless of their community background respondents mentioned printed matter as the most frequent source of information and parents as the least frequent source. Females from small cities and small towns and males from the suburbs maintained the highest parent percentages while rural students listed parents less than all other groups. More than one half of the students felt that they had received sex education too late and in many instances the delay had produced feelings of fear and anxiety about puberty changes about asking questions of parents teachers and friends and about displaying normal emotions around members of the opposite sex. Lack of contraceptive information had resulted in a fair number of forced marriages. For only 1/10 of the respondents did parents provide information at the best time and 2/3 displayed inadequate knowledge of the physiology of sex. Longitudinal studies begun in early childhood and completed in college could provide more accurate information on effective methods of sex education.

The effects of population size and selection intensity in selection for a quantitative character in Drosophila. 3. Analyses of the lines.

1. In order to determine the nature of the genetic variation causing the response to selection in our lines (Joneset al.1968), various analyses were performed.2. There was no consistent change in heritability, estimated from half-sib correlation or from the phenotypic correlation between the bristle numbers of two abdominal segments, after 10 to 20 generations of selection.3. Realized heritabilities over the 10 generations subsequent to the heritability estimations were less than in the early generations but bore little relationship to the estimated values.4. Six lines contained recessive lethals with appreciable effects on bristle number as indicated by high variances, large regression on relaxation and large response to reverse selection.5. Reverse selection lines taken from the main lines at generation 40 indicated that genetic variation was still present in almost all of the lines. Only one line failed to respond to further forward or to reverse selection.6. The three highest lines were crossed in pairs and reselected. Two of the three possible crosses gave further response, exceeding the higher parent after one and three generations, but the other cross failed to pass the highest parent line.7. A combination of large gene effects, linkage, and gene interaction effects have been suggested as the cause of irregularities in the response of the lines. It has not been possible to determine the relative importance of these effects.

Heterosis and Hemeostasis in Secale montanum Guss. ✕ S. cereale L. Hybrids II. Reproductive Characteristics1

F1 hybrids between Secale montanum (P.1.253956) the female parent and three varieties (‘Florida Black,’ ‘Gator,’ and ‘Wrens Abruzzi’) of S. cereale were made. F2 populations were produced by interpollination within each F1 population.Under natural daylength and space‐planted conditions, 40% of the S. montanum plants produced seed in 1965‐66 and 10% in 1966‐67, whereas 100% of the plants in the S. cereale varieties and 70 to 100% of the F1 and F2 plants produced seed. For number of seeds, seed weight, and grain yield, the F1 populations were generally intermediate to the parents with S. montanum the lower parent in all combinations. The F2 populations tended to produce a larger number of seeds than the corresponding F1. Substantial differences resulting from the S. cereale variety involved and year tested were observed. The variability of both the F1 and F2 populations as a result of differences in years and the variation within the F1 populations were greater than the higher parent. However, the S. cereale variety involved was a major factor.With 16‐hr daylength, the F1 populations were generally below or equal to the mid‐parent in percent stainable pollen with S. montanum the lower parent in all combinations. However, the corresponding F2 populations were higher in percent stainable pollen with two out of three combinations exceeding the S. cereale parent. The pollen diameter of the F1 and F2 populations was generally intermediate to the parents with S. montanum the lower parent in all combinations.