Frego Bract Research Articles

A CC-NB-ARC-LRR Gene Regulates Bract Morphology in Cotton.

Bracts are leaf-like structures in flowering plants. They serve multiple functions such as attracting pollinators, aiding tolerance of abiotic stressors, and conducting photosynthesis. While previous studies extensively examine bract function, the molecular mechanisms underlying bract growth remain unknown. Here, the map-based isolation and characterization of a crucial factor responsible for cotton bract development, identified from a mutant known as frego bract (fg), discovered by Frego in 1945 are presented. This gene, named Ghfg, encodes a CC-NB-ARC-LRR (CNL) family protein. Through analysis of bract form in plants with virus-induced gene silencing (VIGS) and transgenic plants, this gene is confirmed to be the causal gene under the fg locus. Furthermore, high-resolution single-cell transcriptomic landscape of cotton bracts is generated, which reveals differences related to auxin in proliferating cells from TM-1 and T582; differences in auxin distribution and ROS accumulation are experimentally verified. These findings suggest that GhFG is in a self-activated state in the fg mutant, and its activity leads to ROS accumulation that impacts auxin distribution and transport. Finally, an island cotton variety with the frego bract trait is developed, demonstrating a novel solution for reducing the high impurity rate caused by bract remnants.

Impact of morphological traits in isogenic cotton lines on consumption-utilization indices of spotted bollworm Earias vittella (Fab) larvae

Consumption-utilization indices of fourth instar Earias vittella larvae on five cotton isogenic lines viz., okra leaf, frego bract, nectariless, red pigmented and glandless were evaluated at a constant temperature of 30 ± 1°C, 70 ± 5% RH and a photoperiod of 16 : 8 L : D. The relative growth rate was more on glandless (0.59) and okra leaf (0.59) and less in red pigmented (0.51). The assimilation efficiency was highest on red pigmented (71.54%) followed by H-777 (70.92%) and lowest on glandless (65.97%). The relative consumption rate was more on nectariless (11.68) followed by H-777 (11.58) and less on frego bract (10.63). The efficiency of conversion of digested food (ECD) and ingested food (ECI) was maximum on glandless (8.56; 5.57) and minimum on red pigmented (6.80; 4.74), respectively. Considering the high total food consumption, growth rate, consumption rate, ECD and ECI of E. vittella, glandless was the most suitable line followed by H-777 whereas frego bract was the least suitable line.

Genetics of Inheritance and Interrelationship of Various Agronomic Traits of F2 Population in Cotton (Gossypium hirsutum L.)

Background: Cotton (Gossypium hirsutum L.) is grown in more than sixty countries worldwide. It is an important fiber crop in the world. It plays a vital role in our national economy being the source of earning of foreign exchange, therefore, it is considered to be the backbone of the economy of Pakistan. In Pakistan, millions of families are associated with cotton and textile industry for their livelihood.
 Results: In this experiment F2 population of the cross L. A. Frego Bract x CIM-600 and their parents was sown in randomized complete block design with three replications during normal growing season of the year 2014 to sort out best performing genotypes for yield related traits. Analysis of variance (ANOVA) revealed that parental and their F2 population showed significant differences for all the observed agronomic traits (plant height, number of monopodia branches, number of sympodial branches, number of bolls per plant, boll weight, ginning out turn, bract type, boll shape, beak size, seed cotton yield, staple length, fiber strength and fiber fineness). Estimation of correlation revealed that seed cotton yield was found positively correlated sympodial branches, fiber fineness and boll weight while ginning out turn, bract type, beak size, staple length and fiber strength were negatively associated with seed cotton yield. Epistasis was not found to be involved in any of the traits.
 Conclusion: The correlation and genetics study of various yield related traits provides us useful information for effective selection and sustainable breeding programs. Estimation of broad sense heritability ( ) in F2 populations for different traits vary as following order; ginning out turn>plant height>seed cotton yield>sympodia branches>fiber length>fiber strength>bolls per plant>monopodia branches>boll weight>fiber fineness with heritability 0.90, 0.79, 0.78, 0.75, 0.73, 0.71 0.67, 0.64, 0.63 and 0.50 respectively. Results suggested form heritability and correlation that these traits can be improved either through appropriate selection method or hybrid breeding programme.

Joint Segregation of High Glanding with Nectariless and Frego Bract in Cotton

There are mutant alleles in the genus Gossypium that increase its tolerance to insect pests. Among the traits that are effective against different insects, high glanding and nectariless increase cotton tolerance to lepidopteran insects, whereas frego bract suppresses the oviposition of the boll weevil, Anthonomus grandis Boheman. The objectives of this research were to transfer the high-glanding trait to frego-bract and nectariless plants. The genotypes used belonged to G. hirsutum: Guazuncho 3 INTA nectariless ne, SP 26 high glanding HG, and SP 47304 frego bract BF. Crosses between SP 26 HG/Guazuncho 3 INTA ne and SP 26 HG/SP 47304 BF and the F2 and F3 generations were obtained. For the combination of high glanding with frego bract, the frequency of individuals with both features varied from 6.4% in the F2 generations to 24.6% in the F3. For the other combination, high glanding with nectariless, the frequency of recombination was of 7.3% in the F2 and 11.8% in the F3. High glanding, nectariless, and frego bract are independently inherited traits in G. hirsutum. Therefore, it is possible to combine the high-glanding trait with frego bracts or nectariless in the same line.

History of Cotton Breeding and Genetics at the University of Arkansas

Cotton breeding research was initiated at the University of Arkansas (UA) in early 1900’s. Early work focused on evaluating cultivars and on making plant selections out of established cultivars. J.O. Ware who began breeding cotton in the early 1920’s studied the genetics and interrelationships of several cotton traits, and released several cultivars. In 1935, he became Senior Agronomist at the United States Department of Agriculture (USDA), Beltsville, MD, then returned to UA in 1950. Several breeders followed Ware at UA. L.M. Humphrey and Ware were responsible for a series of Rowden cultivars. From 1948 until 1986, UA maintained two cotton breeding programs, one on the main campus and the other at the Cotton Branch Station, Marianna, AR. The Marianna program, directed by C.A. Moosberg (1948-1972) and C.W. Smith (1974-1986), was responsible for the release of several Rex cultivars, two stripper cultivars, and Arkot 518. Based on the main campus, B.A. Waddle (1951-1986) continued some of Ware work, and focused on early maturity, seedling vigor, host plant resistance (including the Frego bract trait), and naked and tufted seed. J.McD. Stewart filled the position held by Waddle from 1986 until his death in 2012. His work primarily focused on germplasm exploration and introgression, and cotton biotechnology. In 1988, the two traditional breeding programs were merged into one campus-based program. The program was subsequently moved to the Northeast Research and Extension Center, Keiser, AR, in 1997. F.M. Bourland has led the program since 1988, and has been responsible for almost 100 germplasm and cultivar releases and has established methods for evaluating and selecting several cotton traits. The cotton breeding program at UA continues to develop well-adapted lines and concepts that promote profitable cotton production in Arkansas.

Effects of Field Plot Size on Variation in White Flower Anther Injury by Tarnished Plant Bug for Host Plant Resistance Evaluations in Arkansas Cotton

Field trials conducted in 2008 and 2009 investigated whether plot size affects incidence of white flower anther injury by tarnished plant bug (Lygus lineolaris (Palisot de Beauvois)) in host plant resistance (HPR) evaluations. The three cotton lines evaluated in the trial included a susceptible frego bract line (RBCDHGPIQH-197) and 2 standards, SureGrow (SG) 105 and Deltapine (DP) 393. Samplers monitored white flower anther injury between single row mini-plots embedded within multiple row max-plots. A sub-section of the max-plots was sprayed with insecticides to evaluate these tactics on altering the incidence of white flower anther injury. Plant bug numbers were very low in 2008, while infestation levels were higher in 2009. Significantly higher numbers of flowers with anther injury were observed in both years in the susceptible frego bract line compared to SG 105 and DP 393 lines. In both years, anther injury levels were similar in the max- and mini-plots, with lower levels observed in max-sprayed plots. The white flower monitoring procedure is a consistent indicator of adult plant bug preferences and is not influenced by plot size or interspersions of cultivar lines among plots.

Fine mapping of the fg gene using the interspecific cross of Gossypium hirsutum × Gossypium barbadense

Frego (fg) bract is an important agronomic trait in tetraploid cotton, which has been widely introduced into several cotton varities or lines in the past several years. In order to help us further understand the underlying molecular mechanism of frego bract development, a map-base cloning strategy was used to localize the fg locus. An F2 population which comprised of 290 fg individuals derived from a cross of the multiple-marker line T582 (G. hirsutum, carrying the fg gene) with Hai7124 (G. barbadense) was constructed. Genetic linkage analysis was carried out to map of the fg locus with SSR and EST-SSR markers in tetraploid cotton. Genetic linkage analysis showed that the fg locus was flanked by the marker NAU3016 and NAU3172 on the long arm of chromosome 3, with the genetic distance of 0.3 cM and 4.7 cM, respectively. The information of fg locus provided the basic information for the final isolation of this important gene in tetraploid cotton, these marker information could be used in marker-assisted selection in cotton.

Preferência de Bemisia tabaci biótipo B em linhagens mutantes de algodoeiro

Os efeitos de caracteres mutantes morfológicos do algodoeiro (Gossypium hirsutum L. r. latifolium Hutch.): folha okra, bráctea frego e planta vermelha, em relação à resistência à mosca-branca (Bemisia tabaci biótipo B Hemiptera: Aleyrodidae), foram avaliados em experimentos com ou sem chance de escolha. Os experimentos foram conduzidos em casa-de-vegetação, no delineamento de blocos ao acaso, em fatorial 23 + 1, com quatro repetições. O mutante com a característica planta vermelha foi menos atrativo e menos preferido para oviposição, em relação à planta verde, em ambos os ensaios, com ou sem escolha. Não houve preferência quanto à forma da folha e ao tipo de bráctea.

Mutantes morfológicos de algodoeiro herbáceo como fonte de resistência ao bicudo

Este trabalho teve como objetivo avaliar os efeitos de três características morfológicas mutantes de linhagens de algodoeiro herbáceo (Gossypium hirsutum L. r. latifolium Hutch.), isoladas ou combinadas no mesmo genótipo, como fonte de resistência ao bicudo, Anthonomus grandis Boheman, 1843 (Coleoptera, Curculionidae). O experimento foi conduzido em campo, sob infestação natural, com delineamento de blocos ao acaso e arranjo fatorial 2<FONT FACE=Symbol>´</FONT>3 com um tratamento adicional, com quatro repetições. Em teste com chance de escolha, a característica bráctea frego foi a que apresentou maior redução no dano de oviposição pelo bicudo (34,71%), em relação ao equivalente normal. A folha "okra" reduziu o dano apenas quando associada à bráctea frego (40%). A combinação das três características mutantes na mesma planta proporcionou a menor porcentagem de botões com dano de oviposição (23,13%).

Tests of six cotton (Gossypium hirsutum L.) mutants for association with aneuploids.

Genetic mutants are useful tools for basic and applied research to elucidate the developmental and regulatory processes of the cotton plant (Gossypium hirsutum L.). Their value is enhanced with knowledge of their location in the genome. The results of aneuploid tests used to locate mutant loci on specific chromosomes in G. hirsutum L. are reported. Thirty-four monosomes and telosomes, representing 18 of the 26 chromosomes, were used in combination with six mutants that were associated with nine loci. The mutant loci were glandless stem and boll (gl1gl6), immature fiber (im), Ligon lintless-2 (Li2), methylation (me), nonpinking (np1np2), and Raimondal (Ra1Ra2). We found that im was associated with chromosome 3 that contains linkage group VI (accessory involucre and frego bract); Li2 was associated with chromosome 18 that contains linkage group XVI (open bud and yellow pollen-2); and me was associated with chromosome 9. The remaining three mutants were not associated with the aneuploids in the tests. Knowledge of these chromosome assignments provides a valuable reference for specific studies of mutants and for further genome mapping efforts.

Genetic Trait Effects on Nonlint Trash of Cotton

Genetic traits that reduce seed‐cotton (Gossypium hirsutum L.) trash or improve cleanability should improve lint grade and preserve fiber quality. Onr objective was to evaluate morphological traits that reduce trash and improve cleanability and grade. Twelve near‐isolines involving four leaf shapes (normal, semi‐okra, okra, and superokra) in two genetic backgrounds (LA 213‐613 and MD 65‐11), bract types (normal and frego), and two leaf‐pubescence levels (hairy and semi smooth) were grown for 2 yr at three locations in Louisiana. Seed‐cottun was harvested with a spindle‐picker and ginned on a miniature version of a commercial gin. Amount and type of trash was determined before and after (feeder apron) seed‐cotton cleaning, and after zero, one, and two saw‐type lint cleaners. Semi smooth and super‐okra leaf traits reduced motes by 25 and 15% and small‐leaf trash at the feeder apron by 47 and 20%, respectively, compared with the check. They produced grades similar to the check with one less lint dcaner. Frego‐bract isolines had less leaf and bract trash in lint than the normal‐bract check at any level of lint cleaning. Use of genetic traits such as semi smooth and super‐okra, and to a lesser extent sub‐okra and frego bract, can be used to reduce lint trash and improve cotton grade. Reductions in motes could help reduce the seed‐coat fragment‐white spot (dead fiber) problem in fabric dying.

Regional evaluation of cotton cultivars in eastern Australia, 1974-85

In 1974, a district cotton cultivar trial was initiated to assess the yield and fibre quality of promising cultivars in all major Australian cotton growing areas over 1 or more years. A nearly 5-fold range in site yields (595-2451 kg/ha) occurred across locations and years. Yields were usually higher in the last 6 years of the trial (overall mean 1688 kg/ha) than in the first half (overall mean 1223 kg/ha). Queensland sites (except Theodore) were lower yielding than average, while New South Wales sites (except Warren) were higher yielding. Deltapine cultivars from the U.S.A. have been the dominant commercial cultivars during 1974-85, and in the first 9 years of the trials USA. or Australian-bred Deltapine types produced the highest overall lint yields. Since 1982, Australian-bred Siokra lines have been the highest yielding with their resistance to bacterial blight apparently being an important factor in their performance. The rate of genetic gain in lint yield, as assessed from the overall year means and the mean yield of the 2 control cultivars (Deltapine 16 and Namcala) grown in all 12 years of the trials, was 2.3% per year. These yield increases were also accompanied by improvements in fibre strength and micronaire value in some of the recently developed lines or cultivars. A number of genotypes with mutant traits associated with host plant resistance to insect pests were compared with their near-isogenic counterparts. Superokra leaf yielded 6% less than normal leaf, nectariless yielded similarly to nectaried, and glabrous yielded similarly to delta-smooth pubescence. Frego bract yielded less in 1 comparison but in 2 others was similar to the normal counterpart, while glabrous and frego bract together led to reduced yields. Intra-varietal selection was shown to produce useful gains in yield between 3 to 6.5%.

Effects of the okra leaf, nectariless, frego bract and glabrous conditions on yield and quality of cotton lines

Effects on yield and quality associated with the glabrous leaf, frego bract, okra leaf and nectariless genes (singly and combined) were studied under two insecticide spray regimes (heavy and light) in field experiments repeated over three seasons. Under the heavy spray regime there were few consistent differences between mutant genotypes and the normal except for low yields associated with the glabrous leaf, nectariless, frego bract genotype and the okra leaf genotype. Under the light spray regime, genotypes containing the okra leaf gene and/or the nectariless genes were associated with higher yields than the normal and genotypes containing glabrous leaf and/or frego bract genes were associated with lower yields. Positive epistatic interactions occurred in a number of instances including the okra leaf gene in the glabrous hair, normal bract background under heavy spraying, and with all backgrounds under light spraying, and for glabrous leaf in both the okra normal and okra frego backgrounds under heavy spraying. Nectariless also interacted positively with the normal leaf, normal hair, normal bract background under light spraying. Pronounced negative epistatic interactions only occurred in the light spray regime, and included glabrous leaf in all backgrounds, and frego bract in all backgrounds except the normal leaf, normal hair. The mutant genes had only minor effects on lint quality. The implications of the results for breeding and pest management are diseussed.

Cotton insect resistance studies in the Western cotton growing area of Tanzania

The American bollworm, Heliothis armigera Hub. is the major cotton pest in Tanzania. The commercial cotton varieties have the ability to compensate for early loss of fruiting points caused either by physiological stress or by bollworm damage; and therefore early sowing, together with a blanket spraying regime, is recommended to minimize the damage caused by this bollworm. To extend this integrated approach, studies to incorporate Heliothis -resistant characters, viz. frego bract, nectariless, high gossypol and glandless into the Ukiriguru cotton varities, were started in the early 1970s and are still in progress. To date, frego bract has given consistently good results; and intensive work is under way.

Approach to the Evaluation of Some Factors Affecting Insect Resistance in One ‘Acala’ and Seven Sister Genotypes of Stoneville Cotton in New Mexico

Factors affecting insect resistance in one ‘Acala’ and seven sister genotypes of ‘Stoneville’ cottons were tested from 1 July to 9 September (1,100–2,400 degree-days) at Las Cruces, N.Mex. from 1978 to 1981. There were 98,509 insect counts made and converted to absolute densities. Within the constraints of the experiment, most of the taxa we studied displayed no significant preference for either small or large plots. The nectariless genotype generally had little effect on the density of the insect populations tested. The frego bract, glandless, and okra leaf genotypes tended to support larger phytophagous populations compared with the ‘Stoneville 7A’ check. The smooth leaf genotype tended to support smaller Lygus spp. populations and had an ambiguous effect on populations of predators. The highly glanded genotypes had no effect on the phytophagous populations and had an ambiguous effect on populations of predators. An average of 15% of the check insects were primary consumers, 68% were predators, and 17% were parasites, excluding thrips ( Frankliniella spp.) and those of minor importance. Lygus spp. made up 81% of the primary consumers. Nabis spp. made up 43%, Orius spp. 23%, and Geocoris spp. 12% of the predators. Proctotrupoidea made up 50%, Chalcidoidea 28%, and Ichneumonoidea 14% of the parasites. Predator-prey ratios varied from smooth leaf (4.60) to frego bract (3.03). Smooth leaf supported the smallest number of insects, 23,553, and okra leaf the largest, 32,650.

Changes in growth and development in cotton associated with genes for frego bract and glabrous leaf

Changes to cotton morphology and phenology associated with the frego bract and glabrous leaf genes (singly and combined) were measured in a field experiment using four near isogenic lines. Factorial analysis showed that frego bract was associated with more changes than glabrous leaf and that there were few significant interactions. Frego bract plants were 7% taller than normal bract plants at maturity, exhibited a delay in fruit production, had a greater proportion of fruit on sympodia of monopodial branches, shed more squares and had a lower proportion of reproductive to nonreproductive tissue. Glabrous-leafed plants produced fruit slightly later than hairy-leafed plants and had a lower proportion of reproductive to non-reproductive tissue. Overall, the growth of frego bract and glabrous-leafed plants was not sufficiently different from that of normal plants to warrant changes to the simple fruit model in the commercially available SIRATAC pest management program.

Resistance of Cotton, Gossypium hirsutum L., to Natural Field Populations of Twospotted Spider Mites (Acari: Tetranychidae)1

Natural populations of twospotted spider mites, Tetranychus urticae Koch., infested cotton, Gossypium hirsutum L., in genetic studies in 1980 at three locations near Stoneville, Miss. There were significant differences in spider mite numbers between genotypes. The phenotyphic ranges in spider mite counts per 6.5 cm2 of leaf surface were: test I, 3.9 to 1.4; test II, 12.3 to 6.4; and test III, 4.9 to 3.7. Genotypes developed in the Mississippi delta had the lowest populations of spider mites. Cottons which tended to have high population numbers were Camd-E, Coker 76-118, MO 311, MO 73-1203, UGA 220, TH 149, Delcot, and Coker 201. Okra-leaf cotton had significantly fewer spider mites than frego bract, smoothleaf (Sm2), nectariless, glandless, and normal isolines. Correlation analyses of interest in test I were: spider mites with yield, percent first harvest, and yield first harvest, r = −0.55\*,0.58\*, and 0.25, respectively. In test II, correlations were: r = −0.47*, 0.66** and −0.07, respectively, for yield, percent first harvest, and yield first harvest. Yield data were not obtained from test III.

Effect of Environments and Genetic Backgrounds on Evaluation of Cotton Isolines1

This study was conducted to measure the influence of genetic backgrounds in cotton (Gossypium hirsutum L.) and of environments on the effects that two traits, Okra leaf L02 and frego bract (fg), exert on lint yield and its components. The genetic backgrounds used were DES 24‐8ne, a normal leaf and bract strain; ORH 55, an Okra leaf and frego bract strain; and two F3 plant selections derived from the cross of DES 24‐8ne X ORH 55. For each of the four genetic backgrounds, four near‐isogenic lines were produced among all homozygous combinations of normal vs. Okra leaf and normal vs. frego bract. The 16 genotypes were evaluated for lint yield in 1979 and 1980 under two insect‐control regimes (for a total of four environments). One regime was produced by applying early‐season insecticides; the other was produced by applying no early‐season insecticides and by growing plants of mustard [Brassica juncea (L.) Czern. & Coss.] near the plots to enhancearly‐season insect infestations. Lint yield varied greatly among years, averaging 742 and 479 kg/ha for 1979 and 1980, respectively. Cotton grown with and without early‐season insect control yielded 667 and 554 kg/ha, respectively. The effect of Okra leaf on lint yield and its components was influenced greatly by environments but relatively little by genetic backgrounds. Average yield of Okra and normal leaf types was 597 and 625 kg/ha, respectively. Bract types were more sensitive than leaf types to environments and genetic backgrounds. Normal‐bract isolines, however, yielded more lint in all environments than did their frego‐bract counterparts. The average yield for normal and frego‐bract types grown under the insect control regime was 751 and 582 kg/ha; and under the no control regime was 674 and 435 kg/ha, respectively. Varying environments were more important in the evaluation of these traits than varying genetic backgrounds.

Effects of Okra‐Leaf, Frego‐Bract, and Smooth‐Leaf Mutants on Pink Bollworm Damage and Agronomic Properties of Cotton1

Eight isolines of cotton, Gossypium hirsutum L., which carried all possible combinations of Okra leaf (L°2), frego bract (fg), and Smooth leaf (Sm2) vs. their normal‐leaf and normal‐bract equivalents in the La 71‐7 (a Stoneville) background, were grown in replicated experiments for 3 years in Arizona in insecticide‐free environments. Percentage of seed damage caused by pink bollworm (PBW), Pectinophora gossypiella (Saunders), and 11 agronomic properties were studied.Mean seed damage in the Okra‐leaf isolines was 82% of that in the corresponding normal‐leaf lines, a significant reduction. The Okra‐leaf isolines were comparable to the normal‐leaf types in agronomic properties. Their only negative effect was an 8% lower lint yield (which was significant). Okra leaf interacted with frego bract only for boll size and with Smooth leaf only for seed index. Okra leaf interacted with years for seed damage because the Okra‐leaf isolines had 76% as much damage as the normal‐leaf stocks in 1979, but 85% as much in 1978 and 88% as much in 1980. Seed damage in the frego‐bract isolines was not significantly different from that in its normal‐bract counterparts. Frego bract interacted significantly with Smooth leaf for lint percent and with years for seed damage, total lint yield, bolls/plant, boll size, lint percent, and plant height. When closely examined, the interaction for seed damage suggested that frego bract afforded a slight advantage during the years when seed damage was relatively high. However, deficiencies in numerous agronomic properties (including a 24% lint yield reduction) and the five year ✕ agronomic property interactions offset any advantages in reduced seed damage afforded by frego bracts. Smooth‐leaf isolines unexpectedly displayed more seed damage than the hirsute‐leaf lines. Smooth‐leaf isollnes were also inferior to the hirsute‐leaf types in all agronomic properties except seed index and displayed significant interactions between years and percent lint yield at second and third harvest, total lint yield, bolls/plant, and date of first flower. For PBW resistance and agronomic performance, Okra leaf appears to have value, frego bract does not, and Smooth leaf must be reevaluated.

Boll Weevill Oviposition on Frego Bract Cotton1

Oviposition and survivorship were determined of Anthonomus grandis grandis Boheman on caged normal bract, frego bract, and frego bract-red leafed cotton. No differences were found. In field studies, when frego bract and normal bract plots were surrounded with a 3-m sudan barrier, released boll weevils damaged equal numbers of flower buds. Our conclusion was that frego bract offers no resistance to the boll weevil.