Number Of Florets Research Articles

Changes in Number and Weight of Wheat and Triticale Grains to Manipulation in Source-Sink Relationship

The source-sink ratio experimental manipulation has helped to define whether a crop is limited by source or sink or co-limited by both. There is no evidence in triticale of source-sink manipulations effects on yield and yield components. Two experiments were accomplished during 2008 and 2009 growing seasons at the Universidad Autónoma del Estado de México, México, and one in 2010 at the National Institute of Agricultural Technology in Pergamino, Argentina. Two triticale cultivars (line 4 and 7) and one wheat cultivar (Tollocan) were used. Source-sink relations were modified at anthesis by thinning, degraining, shading, and total defoliation procedures. Changes in the source-sink relation affected yields in both species differentially. The changes in yield due to cultivars and treatments were explained mainly by the number of grains rather than by their individual grain weight. The number of grains was affected by all treatments in both species, while the individual grain weight was increased by thinning and degraining mainly in triticale. A greater number of fertile florets in triticale were associated with their higher rate of abortion compared to wheat. These results could help to better understand crop management and genetic improvement.

Grasses of the Great Plains by James Stubbendieck, Stephen L. Hatch, and Cheryl D. Dunn

Reviewed by: Grasses of the Great Plains by James Stubbendieck, Stephen L. Hatch, and Cheryl D. Dunn Clenton E. Owensby Grasses of the Great Plains. By James Stubbendieck, Stephen L. Hatch, and Cheryl D. Dunn. College Station: Texas A&M University Press, 2017. 736 pp. Illustrations, figures, maps, line drawings, selected references, index. $50.00 cloth. Those of us faced with the arduous but rewarding task of teaching grass identification have been given a new and excellent resource. As a veteran of more than 50 years of teaching "Range Grasses" at a Great Plains university, I am excited by the addition of another resource, one that I can honestly say is better than any other available for identification of Great Plains grasses. The comment I often hear, that all grasses look alike, can be cast aside through the assiduous use of this outstanding tome. The Harvard zoology professor Louis Agassiz championed astute, detailed observations coupled with comparison. His "look at the fish" test for students who chose to work with him stressed the importance of looking at detail. Fortunately, this manual provides very detailed line drawings that show minute but important morphologic differences, particularly at the species level. Also included are the necessary drawings to distinguish inflorescence, stem, spikelet, and floret morphology. The keys used in identification diverge from the traditional subfamily and tribe separation introduced by A. S. Hitchcock's Manual of the Grasses of the United States by grouping different genera and species with similar morphologic characteristics, such as number of florets or attachment of spikelets. That approach greatly reduces the keying steps for many species and improves accuracy. I heartily approve of the approach and have used it in constructing my own keys for Kansas grasses. The species are listed in alphabetic order, which aids in quick access to a known plant. The checklist of species at the beginning includes both synonyms and the current taxonomy. That is a boon for those of us who learned little bluestem as an Andropogon rather than a Schizachyrium. The noted Texas A&M agrostologist Frank Gould and I had a lively discussion about that change! The glossary is a critical part of a grass manual, and the one in this manual is very inclusive. The foreign language of grass taxonomy requires frequent visits to the glossary, particularly for the novice. The overall description of the Great Plains gives the reader a valuable overview of the region and its diversity, which undergirds the wide diversity of grass species present in the region. The most impressive feature of the manual lies in the excellent line drawings of each grass species. The detail of the drawings will be invaluable to the user in getting it right. I heartily recommend this book for use by academics, students, agency professionals, and hobbyists. I certainly will be using it in both the classroom and in the field. Clenton E. Owensby Department of Agronomy Kansas State University Copyright © 2019 Center for Great Plains Studies, University of Nebraska–Lincoln

Double Flower Freesia ‘Sweet Lemon’ with Strong Fragrance

Freesia (Freesia hybrida Hort.) ‘Sweet Lemon’ was developed for the cut flowers in National Institute of Horticultural Herbal Science, Rural Development Administration, Korea in 2015. This hybrid was crossed and selected from ‘Teresa’ and ‘Yvonne’ in 2007. Morphological characteristics of the selected freesia hybrid were investigated for 5 years from 2009 to 2014, and then it was named ‘Sweet Lemon’ in 2015. ‘Sweet Lemon’ has double and lemon petals (RHS color chart Y2B). The average flower diameter was 6.8 cm and the average yield is 6.7. The growth of the plant is vigorous and the average plant height is 99.0cm, which is 34.7cm higher than the standard cultivar ‘Yvonne’. The average floret number per stalk of ‘Sweet Lemon’ was 10.7, and stalk length was 7.7 cm. The average days to first flowering of ‘Sweet Lemon’, 126 days, was approximately 20 days earlier than the control cultivar. It’s average vase life and yield is 8.7 days and 5.6 cormlets per plant, respectively. Totally 58 of volatile compounds were identified using gas chromatography-mass spectrometry (GC-MS), the major components were linalool, alpha-terpineol, alpha-selinene, and limonene.

МОРФОЛОГИЧЕСКИЕ ОСОБЕННОСТИ СОЦВЕТИЙ ТОПИНАМБУРА (HELIANTHUS TUBEROSUS L.) ПО МАТЕРИАЛАМ КОЛЛЕКЦИИ ВИР

Background. Jerusalem artichoke (Helianthus tuberosus L.) is a valuable crop grown for feed, food, industrial and medicinal purposes. Studying biological, geographic, environmental, taxonomic and other features of this species is a vital task, whose solution will help, first of all, to disclose the variability of its traits, develop its intraspecific system, and work out methods for researching into the morphology of Jerusalem artichoke. Analyzing morphological features of its inflorescence and flower is one of the basic components of such a study. Materials and methods. The material for the research was the collection of Jerusalem artichoke maintained in a live condition at Maikop Experiment Station. The inflorescences of 58 accessions were analyzed to investigate eleven traits. Statistical analysis was carried out using StatSoft’s Statistica 13.0 software package. Results and conclusion. The greatest differences among the groups, formed according to geographic origin, were observed in the number of inflorescences per plant and the number of false ligulate florets in the inflorescence. The length of tubular florets was constant within the species, being 1.4 cm; as the most stable trait, this descriptor probably may be used as a diagnostic tool for this species. The accession ‘Sakhalinsky Krasny 4’ (Sakhalin population of Japanese origin) was the most distinctive, as regards the set of its characteristics.

Photoperiod-sensitivity genes shape floret development in wheat.

Lengthening the pre-anthesis period of stem elongation (or late-reproductive phase, LRP) through altering photoperiod sensitivity has been suggested as a potential means to increase the number of fertile florets at anthesis (NFF) in wheat. However, little is known about the effects that the Ppd-1 genes modulating plant response to photoperiod may have on reproductive development. Here, five genotypes with either sensitive (b) or insensitive (a) alleles were grown in chambers under contrasting photoperiods (12 h or 16 h) to assess their effects. The genotypes consisted of the control cultivar Paragon (three Ppd-1b) and four near-isogenic lines of Paragon with Ppd-1a alleles introgressed from: Chinese Spring (Ppd-B1a), GS-100 (Ppd-A1a), Sonora 64 (Ppd-D1a), and Triple Insensitive (three Ppd-1a). Under a 12-h photoperiod, NFF in the genotypes followed the order three Ppd-1b > Ppd-B1a > Ppd-A1a > Ppd-D1a > three Ppd-1a. Under a 16-h photoperiod the differences were milder, but three Ppd-1b still had a greater NFF than the rest. As Ppd-1a alleles shortened the LRP, spikes were lighter and the NFF decreased. The results demonstrated for the first time that Ppd-1a decreases the maximum number of florets initiated through shortening the floret initiation phase, and this partially explained the variations in NFF. The most important impact of Ppd-1a alleles, however, was related to a reduction in survival of floret primordia, which resulted in the lower NFF. These findings reinforce the idea that an increased duration of the LRP, achieved through photoperiod sensitivity, would be useful for increasing wheat yield potential.

Weed-competitive ability of a hybrid and an inbred rice cultivar in managing Ischaemum rugosum in dry-seeded rice

Ischaemum rugosum Salisb. commonly known as ribbed murainagrass is a problematic herbicide-resistant weed in directseeded rice systems. To evaluate the competitive ability of rice cultivars against I. rugosum, a study was established with two rice cultivars (Mestiso 21, a hybrid and IR 64, an inbred). These cultivars were sown at density of 4 plants per pot with four different densities of I. rugosum (0, 2, 4, and 8 plants pot(-1)). Across weed density levels, IR 64 had 14% lower while Mestiso 21 had 20% higher plant height than I. rugosum. In competition with eight I. rugosum plants per pot, Mestiso 21 had 17% higher plant height (85 cm) than of IR 64 (73 cm). Without competition, IR 64 had higher tiller number, leaf number, leaf area, and root biomass than Mestiso 21 while in competition with eight weed plants per pot, Mestiso 21 had higher leaf biomass (29%), stem biomass (13%), specific stem length (38%), panicle biomass (29%), florets number (41%), and florets biomass (36%) than IR 64. In comparison with control (no weed competition), weed densities of 2, 4, and 8 plants pot(-1) reduced the total rice biomasses and grain yields by 32, 42, and 50%; and 26, 46, and 56% for IR 64 and by 23, 37, and 45%; and 20, 28, and 42% for Mestiso 21, respectively. The Mestiso 21 reduced the I. rugosum plant height, number of tillers, leaf biomass, inflorescence biomass, root biomass, and total aboveground biomass by 16.3, 0.3, 22.1, 31.3, 21.8, and 22.7%, respectively, compared with IR 64. The results of this study suggest that the hybrid rice Mestiso 21 has a better competitive ability to suppress I. rugosum than IR 64 therefore can be used in an integrated weed management of problematic weeds in direct-seeded rice systems.

Evaluating the Effect of Different Planting Dates on Panicle Growth Trend and Performance of Rice Varieties in Khuzestan Region, Iran

This study was aimed at evaluating the effect of different planting dates on the panicle growth trend (length, weight, and branches of panicle) and the performance of rice varieties in the north of Khuzestan province with east latitude of 48 o: 28 ◌َ and north longitude of 31 o: 50◌ executed as spilt plots in the form of randomized complete blocks with three repetitions. Main factor was the date of planting at three levels (June 5th, June 20th, and July 5th) and the secondary factor includes the varieties of red Anbori (tall and short grains), and Champa. Results indicated that the maximum performance of the seed, floret in panicle, and weight belonged to the date of July 5th and the maximum length of panicle and branches, without significant difference, be longed to the second date of planting. evaluating the growth trend, maximum increase (rate of growth) of the dry weight and number of floret was due to the more-appropriate heat and the reduction of sterility as well as a more demand for non-structural carbohydrates (unlike the planting date of June 5th) in the planting date of July 5th, but the length of panicle had its most growth rate in the first two planting dates, while the number of branches was not affected by the date of planting. Among the varieties, Champa , with an average of 3795/4 kg/ha , had the maximum efficiency . Based on the results of this study, by focusing on the modifying objectives to increase the dry weight of the panicle, because of its positive and high correlation (0/759**), increase of the rice seed`s efficiency can be hopefully predicted.Keywords: dates of planting, rice, growth trend, panicle

QTL Mapping of Six Spike and Stem Traits in Hybrid Population of Agropyron Gaertn. in Multiple Environments.

Most Agropyron Gaertn. species are excellent sources of forage. The derivative lines of wheat-Agropyron cristatum show elite agronomic traits, and some are valuable for wheat breeding. The species of Agropyron Gaertn. was mainly recognized by the spike morphology in traditional taxon. Six traits, including spike length (SL), ear stem length (ESL), the second internodes length (SIL), spikelet number per spike (SNS), floret number per spikelet (FNS), and grain number per spikelet (GNS), are vital to morphology studies and also influences the forage crop yield. To elucidate the genetic basis of spike and stem traits, a quantitative trait locus (QTL) analysis was conducted in a cross-pollinated (CP) hybrid population derived from a cross between two diverse parents, Agropyron mongolicum Keng Z2098 and A. cristatum (L.) Gaertn. Z1842, evaluated across three ecotopes (Langfang, Changli, and Guyuan of Hebei, China) over 3 years (from 2014 to 2016). Construction of a high-density linkage map was based on 1,023 single-nucleotide polymorphism (SNP) markers, covering 907.8 cM of the whole Agropyron genome. A total of 306 QTLs with single QTL in different environments explaining 0.07–33.21% of the phenotypic variation were detected for study traits. Seven major-effect QTLs were identified, including one for ESL on chromosome 3, one for SIL on chromosome 5, three for SL (two on chromosome 2 and one on chromosome 4), and two for SNS on chromosomes 3 and 7. Also, seven stable QTLs, including four for ESL, one for SL, one for GNS, and one for FNS, were mainly mapped on chromosomes 2, 3, 4, 5, and 7, respectively, elucidating 0.25–14.98% of the phenotypic variations. On the use of Agropyron CP hybrid population to identify QTL determining spike and stem traits for the first time, these QTLs for six traits would provide a theoretical reference for the molecular marker-assisted selection in the improvement of forage and cereal crop species.

SUNFLOWER OIL YIELD RESPONSES TO PLANT POPULATION AND ROW SPACING: VEGETATIVE AND REPRODUCTIVE PLASTICITY

Attempts have not been made to increase the potential yield of sunflower via the combined use of high plant populations and crowding-tolerant cultivars, an approach that has been successful in maize -another strong apical dominance crop. This may be due to the negative effects of increased disease pressure and increased susceptibility to lodging at high sunflower plant populations. Information on crop yield responses to plant populations higher than usual recommended commercial plant populations is also limited. Wide inter-row spacing could shift crop water consumption towards later developmental stages with positive effects on yield in seasons of low rainfall, but might also limit crop yields in years with good rainfall. Here we report on studies aimed at examining yield (both oil and total biomass) responses to changes in plant population at two inter-row spacings: 0.7 and 1.4 m, in crops grown without restrictions due to water or nutrients, and protected from insects and diseases. Oil yields in the 0.7 m row spacing treatments increased over the whole of the 2.0-14.3 plants m-2 range, reaching values much greater than those obtainable at the current commercial plant population of around 5.1 plants m-2. This increase reflected a continuous increase with increased plant population for total crop biomass, together with an unchanging harvest index. Over the 2-7 plant m-2 range of plant populations shared between the two row spacing treatments yields were not affected by spacing. Vegetative and reproductive plasticities, as reflected in the responses of biomass and plant leaf area at mid-anthesis to ground surface area per plant (vegetative plasticity indicators) and oil yield per plant to ground surface area per plant (reproductive plasticity indicator) did not vary over the 2.0-14.3 plant m-2 plant population range in either row spacing. In the 0.7-m row-spaced crops, reproductive plasticity was less than vegetative plasticity and a similar tendency was observed at the 1.4-m row spacing. Floret number and achene number per plant together with unit achene weight decreased over the 2.0-14.3 plant m-2 range for both row spacings, while fertility ratio over the same range was stable. Over the same range of plant population, achene oil concentration fell slightly, while achene oil content increased slightly and then stabilised. The study of the genetic basis of the plasticities found in this work should contribute to breeding programs aimed at increasing crop tolerance to high plant population densities.

Studies on Effect of Planting Dates and Varieties on Growth and Quality in Gladiolus (Gladiolus hybridus Hort.) Under Sub-Humid Zone of Rajasthans

A field experiment was conducted during winter season of 2015-16 to study 'Studies Effect of Planting Dates and Varieties on Growth and Quality on Gladiolus (Gladiolus hybridus Hort.) under sub-humid zone of Rajasthan' having 15 treatment combinations of five Varieties (V1- African Star, V2- Hunting Song, V3- Legend, V4- Pusa Srijana and V5- Snow Princess) and three planting dates (D1- 10th October, D2- 25th October and D3- 9th November). The treatment V2D1 (Hunting Song + 10th October planting) recorded the maximum plant height (116.10 cm), highest number of leaves per plant (8.77), main stem diameter (1.50 cm), number of florets per spike (15.8), spike length (91.80 cm), rachis length (57.90 cm), floret diameter (10.04 cm), vase life of spike (13 days), While the maximum leaf length (64.20 cm), leaf width (4.96 cm) in (V5D3) and maximum spike girth (0.91cm) was found in (V1D2). The growth and flowering quality was found superior in compare to other planting dates.

Contribution of main culm and tillers to grain yield of durum wheat: Influence of sowing date and plant traits

The question of whether tillers are a burden or a resource in durum wheat is of concern in the variable Mediterranean climates. The contribution of tillers to grain yield was investigated in commercial cultivars differing in time to anthesis, tillering and spike size, in response to three sowing dates:mid-autumn (recommended), winter, and early spring. The thermal time of phenological phases was calculated, and yield-components and floret production were analysed separately in main culm and tillers. Tiller spikes showed higher spikelet abortion coupled to lower spikelet fertility and mean kernel weight, so that grain yield was 40-60% lower than in main culm spikes. Despite this, tillers contributed 35 to 50% to plant yield. The sowing date affected tiller number rather than one tiller yield. In winter sowings (December), lower main culm yield was fully compensated by increased tiller yield, whereas shifts of sowing date to early spring (February) reduced tillering, which caused a yield loss ranging from 12 to 20%. Cultivars differed in one tiller yield rather than in tiller number, and higher grain yield of tillers was primarily due to increased grain recovery. A more equal partitioning of resources within main culm and tillers corresponded to better yield stability across sowing dates. Starting from this, we suggest that early anthesis, a long stem elongation phase, a high primordium initiation-rate and small spikes, could be positive traits for durum wheat yield stability in changing environments, since they allow plants directing more time and resources to floret production and grain filling both in main culm and tiller spikes. From a methodological point of view, our results show that the number of fertile florets per spike is highly correlated with the average floret number of five given spikelets.

Physiological determinants of fertile floret survival in wheat as affected by earliness per se genes under field conditions

Abstract Variations in wheat yield are largely explained by changes in grain number per m2 which is linked to the number of fertile florets at anthesis. This, in turn is the outcome of developmental processes which control floret initiation and mortality. Earliness ‘per se’ (Eps) genes are involved in fine-tuning time to anthesis in wheat (and other cereals) but their effect on development prior to anthesis is less well studied. We aimed to determine effects of Eps genes on spike fertility, quantifying aspects of floret developmental which influence this trait. Field experiments were carried out to record floret primordia generation/degeneration dynamics in near isogenic lines (NILs) with contrasting Eps alleles (late flowering vs early flowering alleles; Eps-late and Eps-early, respectively) derived from the Avalon x Cadenza (AxC) cross with the Eps gene on either chromosome 1D or 3 A and from the Spark x Rialto (SxR) cross with the Eps gene on chromosome 1D. Eps NILs varied in spike fertility: Eps-late alleles increased fertility. Although the effect was in general slight, the magnitude was affected by the particular alleles and the cross used to produce the NILs. Differences in the number of fertile florets were explained by differences in the dynamics of floret development. NILs with Eps-late alleles improved the development of a small number of labile florets allowing them to complete their development to become fertile florets instead of dying, as in lines carrying early alleles. Thus, these alleles improved floret fertility mainly through reducing the rate of floret mortality with no influence on the dynamics of floret primordia initiation or in maximum number of floret primordia. Therefore, Eps genes could be exploited in wheat breeding not only to fine-tune time to anthesis but also to improve spike fertility.

Statistical Modeling of Phenotypic Plasticity under Abiotic Stress in Triticum durum L. and Triticum aestivum L. Genotypes

Future challenges to the role of durum and bread wheat in global food security will be shaped by their potential to produce larger yields and better nutritional quality, while increasingly adapting to multiple biotic and abiotic stresses in the view of global climate change. There is a dearth of information on comparative assessment of phenotypic plasticity in both wheat species under long-term multiple abiotic stresses. Phenotypic plasticities of two durum and bread wheat genotypes were assessed under increasing abiotic and edaphic stresses for six years. Combinations of normal and reduced length of growing season and population density, with or without rotation, generated increasing levels of competition for resources and impacted phenotypic plasticity of several plant and yield attributes, including protein and micronutrients contents. All the phenotypic plasticity (PPs) estimates, except for the C:N ratio in both genotypes and grain protein content in T. aestivum genotype, were impacted by abiotic stresses during the second stress phase (PS II) compared with the first (PS I); whereas, covariate effects were limited to a few PPs (e.g., biomass, population density, fertile tillers, grain yield, and grain protein content). Discrimination between factor levels decreased from abiotic phases > growth stages > stress treatments and provided selection criteria of trait combinations that can be positively resilient under abiotic stress (e.g., spike harvest and fertility indices combined with biomass and grain yield in both genotypes). Validation and confirmatory factor models and multiway cluster analyses revealed major differences in phenotypic plasticities between wheat genotypes that can be attributed to differences in ploidy level, length of domestication history, or constitutive differences in resources allocation. Discriminant analyses helped to identify genotypic differences or similarities in the level of trait decoupling in relation to the strength of their correlation and heritability estimates. This information is useful in targeted improvement of traits directly contributing to micronutrient densities, yield components, and yield. New wheat ideotype(s) can be designed for larger grain yield potential under abiotic stress by manipulating yield components that affect kernels m−2 (e.g., number of tillers, number of florets per spikelet, and eventually spike fertility and harvest indices) without impacting nutrient densities and kernel weight, thus raising harvest index beyond its current maximum.

Genetic analysis of the corolla tube merged degree and the relative number of ray florets in chrysanthemum (Chrysanthemum × morifolium Ramat.)

Abstract Flower type is an important quality trait of ornamental plants. Mastering genetic variation in flower types is of practical significance for breeding improved flower types. Chrysanthemum (non-anemone type) flowers consist of several elements; both ray floret shape and the relative number of ray florets (RNRF) on the capitulum are very important factors. However, until recently, few reports have standardized chrysanthemum flower type evaluations, hindering the development of genetic studies of chrysanthemum flower types. In this study, as an important index of ray floret shape, the corolla tube merged degree (CTMD) was defined as the corolla tube length/ray floret length (CTL/RFL). In addition, the number of ray florets/number of florets (NRF/NF) was used to describe the RNRF on the capitulum. Major gene and polygene mixed inheritance analyses were conducted based on 2 F1 populations from 2 pairs of parents that strongly differed in the CTMD and RNRF. ANOVA revealed that all traits strongly significantly differed among the different hybrids, and correlation analysis revealed that the CTMD and RNRF might have evolved independently. Additionally, according to the Q-mode cluster analysis results, we divided the RNRF into 4 levels: single, semi-double I, semi-double II and double. Genetic analysis revealed that both the CTMD and RNRF could be described by a B-2 genetic model via two additive-dominance major genes. In addition, the heritability of the major genes for these traits was greater than 50%, indicating that the CTMD and RNRF were controlled mainly by genetic factors. These results will provide a new theoretical basis for further improvement and breeding of chrysanthemum flower types.

Downregulation of OsAGO17 by artificial microRNA causes pollen abortion resulting in the reduction of grain yield in rice

Background: Pollen development is an important reproductive process that directly affects pollen fertility and grain yield in rice. Argonaute (AGO) proteins, the core effectors of RNA-mediated silencing, play important roles in regulating plant growth and development. However, few AGO proteins in rice were reported to be involved in pollen development. In this study, artificial microRNA technology was used to assess the function of OsAGO17 in pollen development. Results: In this study, OsAGO17, a rice-specific gene, was specifically expressed in rice pollen grains, with the highest expression in uninucleate microspores. Downregulation of OsAGO17 by artificial microRNA technology based on the endogenous osa-miRNA319a precursor was successfully achieved. It is found that downregulation of OsAGO17 could significantly affect pollen fertility and cause pollen abortion, thus suggesting that OsAGO17 functions in rice pollen development. In addition, the downregulation of OsAGO17 mainly caused a low seed-setting rate, thereby resulting in the reduction of grain yield, whereas the downregulation of OsAGO17 did not significantly affect rice vegetative growth and other agricultural traits including number of florets per panicle, number of primary branch per panicle, and 100-grain weight. Furthermore, the result of subcellular localization analysis indicated that the OsAGO17 protein was localized to both the nucleus and the cytoplasm. Conclusion: These results represent the first report of the biological function for OsAGO17 in rice and indicate that OsAGO17 may possibly play crucial regulatory roles in rice pollen development. It helps us to better understand the mechanism of pollen development in rice.

Root-zone cooling improves fruit production in high sugar content tomato

The high-sugar content tomato is becoming popular because of its sweetness in Japan. However, the production of high-sugar content tomatoes in summer has been unstable especially in number of fruit set. Root-zone cooling is known to have an advantage to increase tomato yield in the summer and the effect of root zone cooling was evaluated in the production of high-sugar content tomato. High-sugar content tomatoes were grown at 2 kinds of plots, 15 and 25°C, in root-zone temperatures (RZT) from December 12, 2015 to February 13, 2016. During the experiment, the average air temperature was 21.8°C. During the daytime (9:00-17:00) the temperature was on average 24.2°C and during the nighttime (17:00-9:00) it was 20.7°C. The number of fruits per cluster was 3.3 in 15°C-RZT and 2.6 in 25°C-RZT. The floret number was larger and the flowering rate (the number of anthesis/floret emerged) was higher in the 25°C-RZT than in the 15°C-RZT. This phenomenon showed the possibility to improve the yield of high-sugar content tomatoes. The present examination was done in winter. It is necessary to perform this kind of examination in summer, over 30°C day temperature.

EFFECT OF SOAKING WITH GIBBERELLIC ACID AND SPRAYING WITH HUMIC ACID AND SEAWEED EXTRACT IN SOME FLOWERING CHARACTERISTICS OF GLADIOLUS CV. CHINON

نفذت التجربة في بيت بلاستيكي تابع لمحطة أبحاث قسم البستنة وهندسة الحدائق – كلية الزراعة – جامعة ديالى للفترة من 1/11/2016 إلى 1/6/2017 لدراسة تأثير نقع كورمات الكلاديولس بحامض الجبرلين بثلاثة مستويات (0، 100، 200)ملغم. لتر-1 والرش الورقي بحامض الهيومك بثلاثة مستويات (0، 0. 3، 0. 5)غم. لتر-1 ومستويين من مستخلص الأعشاب البحرية (0، 0. 5)غم. لتر-1 بواقع ثلاث رشات عند بلوغ النبات مرحلة الورقة الثانية والرابعة والسادسة، في بعض صفات النمو الزهري. أدت المعاملة بتركيز 100 ملغم. لتر-1 إلى أفضل النتائج في المدة اللازمة لتفتح الزهيرة القاعدية 118. 670 يوم وطول النورة الزهرية 46. 339سم وقطر النورة الزهرية 156. 181ملم وطول الشمراخ الزهري 85. 640سم والوزن الطري للشمراخ الزهري 57. 714غم في حين أدى التركيز 200ملغم. لتر-1 إلى أفضل النتائج في صفات قطر الزهيرة القاعدية 106. 861ملم وعدد الزهيرات 13. 084زهيرة والعمر المزهري 8. 083يوم. أدت معاملة الرش بحامض الهيومك بتركيز 0. 3غم. لتر-1 إلى أفضل النتائج لصفات المدة لتفتح الزهيرة القاعدية 117. 606يوم وقطر الزهيرة القاعدية 103. 742ملم وقطر النورة الزهرية 155. 445ملم في حين أدى التركيز 0. 5غم. لتر-1 إلى أفضل النتائج في طول النورة الزهرية 45. 805سم وطول الشمراخ الزهري 85. 407سم والوزن الطري للشمراخ الزهري 59. 437غم. أدت معاملة الرش بمستخلص الأعشاب البحرية إلى فروقات معنوية في المدة لتفتح الزهيرة القاعدية 120. 003يوم وطول الشمراخ الزهري 84. 407سم والوزن الطري للشمراخ الزهري 56. 331غم. كان لجميع التداخلات الثنائية والثلاثية تأثير معنوي في الصفات المدروسة باستثناء التداخل بين حامض الهيومك ومستخلص الأعشاب البحرية في صفة عدد الزهيرات. نورة-1.

Stephanomeria occultata (Asteraceae: Cichorieae), a New Species of Wirelettuce from Northern Utah, and a Key to all Perennial Wirelettuce

Stephanomeria occultata, a new diploid (2n = 16) species of wirelettuce endemic to the Weber River drainage of northern Utah, is herein described, and a key to all perennial members of the genus is provided. The populations of S. occultata occur in unstable gravelly slopes in close proximity to the Weber River between 590–1650min elevation. Stephanomeria occultata is characterized from other species in the region by its large growth habit, which is up to 1mtall, numerous stems, well-developed tomentose leaves, and large number of ray florets (8–14). Information on habitat, ecology, distribution, taxonomic relationships, conservation, as well as maps, photographs, and illustrations are provided. The two populations of S. occultata may contain as few as 200 genets with up to 500 ramets and these small populations are vulnerable to encroaching weeds and anthropogenic disturbance.

Variation in floral and growth traits in a macadamia breeding population

Macadamias are grown commercially around the world for their edible nuts. Identifying elite macadamia breeding selections with high yield potential is difficult due to the polygenic control of the trait, and more importantly the low heritability of yield. Indirect selection for yield may be possible through identification of correlated traits that have higher heritability, and are more efficiently measured. This study aimed to investigate component traits for yield by dissecting floral and growth traits of macadamia, including: raceme length, rachis width, floret density, number of florets raceme-1, raceme density, and trunk circumference. This is a preliminary study of 143 seedling progeny from 33 families across two sites in Bundaberg, Queensland, Australia, planted between 2001-2003. Average raceme lengths were variable between families, ranging from 10.2 cm in the '344' × '804' family to 21.1 cm in 'A38' × '816' progeny. Raceme length was significantly correlated with number of florets per raceme (rp=0.85 and rg=0.91, p<0.001), whilst raceme length was negatively correlated with floret density (rp=-0.30, p<0.001). Raceme length, raceme density and number of florets raceme-1 were statistically different between families (p<0.01). This paper shows that it is useful to identify component traits that may be more efficient to measure in order to indirectly select for complex traits like yield. These are preliminary findings of a larger study in which flowering characteristics will be compared with nut and shell characteristics and yield. Additionally, these findings will inform genomic selection models for yield prediction, as well as genome wide association studies for component traits.

Morpho-phenology and chromosome number of Iranian Bromus danthoniae Trin. genotypes

ABSTRACT- Bromus danthoniae Trin. is an annual grass species which grows mainly on dry grassy rocky mountain slopes and grassy steppe, and is grazed by many herbivores and recognized as a useful pasture plant. The chromosome number, morphological and anatomical traits of 82 genotypes of B. danthoniae belonging to three sub-taxa were investigated. Twenty-seven quantitative and 20 qualitative morphological traits were evaluated. The results of analysis of variance showed that B. danthoniae genotypes varied significantly for all quantitatively tested traits. Based on cluster analysis, the genotypes were divided into four groups which mostly corresponded to their subspecies identities. According to correlation analysis, lemma length had strong positive correlations with other traits such as awn length (r=0.55**), lemma width (r=0.72**) and caryopsis length (r=0.84**). In addition, lemma width was significantly correlated with the traits like floret number per spikelet (r=0.47**) and caryopsis length (r=0.58**). Based on factor analysis, the first three factors encompass about 51% of total variation. Overall, lemma length and lemma width were the two reliable traits for morphological investigations in this species. The results of chromosome counting showed that B. danthoniae subsp. danthoniae and B. danthoniae var.lanuginusos Roshev. were diploid (2n=2x=14) whereas B. danthoniae subsp. pseudodanthoniae (Drobov) H. Scholz was tetraploid (2n=4x=28). The results of leaf surface anatomy showed that tetraploid genotypes had larger stomata but lower stomatal density than the diploid ones, thus a comprehensive relationship between genome size and guard cell size cannot be ruled out as a plausible explanation for differentiating the ploidy levels. The high morphological variations among the B. danthoniae genotypes explain the habitat distribution of this species and enable us to incorporate this knowledge into practice by exploiting the variation for improvement of pasture production.