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Forty F1 crosses obtained from 5 × 8 line by tester mating design methodology were studied. The varieties Chirpan-539, Sirius, Darmi (Bulgarian selection), Nazili 954 (Turkish) and FR-H-1002 (Spanish) were used as female parents, selection lines 449, 489, 639, 535, 550, 572, 578 and 678 were used as male parents. The aim of the study was to identify the best F1 crosses for improving lint percentage and fiber length in new cotton varieties, by applying a new approach to select parents with the highest possible general combining ability (GCA) for both traits. Crosses and their parents were sown in one row, randomized in three replications. The highest values of the GCA effects of the two parental forms for each trait were taken as “ideal” and the Euclidean distances between them and the GCA effects of the two parents for each F1 cross were calculated. Combining ability analysis of variance showed that females and males differed in general and specific combining abilities. The cultivars Chirpan-539 and Nazili-954 from the females, and lines 550 (Tiara variety) and 578, from the males, appeared to be very good general combiners for lint percentage. The cultivar FR-H-1002 and Darmi variety, from the females, and lines 449, 572, and 578, from the males, appeared to be very good general combiners for fiber length. Some crosses showed high positive SCA effects and heterosis for both traits. Cross combinations FR-H-1002 × 578, Darmi × 578 and Nazili 954 × 578 had the highest possible GCA for both studied traits and are most valuable for selection programs. A total of seven crosses with short Euclidean distances to the “ideal” population in which desirable segregates are expected to occur were selected. [ABSTRACT FROM AUTHOR]

On the basis of established high indicators for the most economically valuable traits, specialized trait collections have been created as starting material for the various selection directions in cotton: specialized collection for high productivity; specialized collection for fiber length improvement and other quality indicators; specialized collection for higher lint percentage. Organization of the relevant collections was in accordance with the requirements of selection process for a complex evaluation as biological and economic qualities, adaptability to the specific conditions and others. With these, commercial geneplasm will be preserved, the varietal structure and the hereditary basis of Bulgarian selection will be enriched and expanded. Created specialized trait collections will facilitate the use of available genetic resources in the various directions of cotton breeding and are the basis for creating new cotton varieties with higher productivity and improved fiber quality. [ABSTRACT FROM AUTHOR]

Background:wis a disease with constantly rising economic and social burden; it is associated with multiple comorbidities which contribute to the disease severity.

The aim of this research was to study the productive potential and evaluate the fiber properties of the new Selena cotton variety. The variety was studied in competition variety trials conducted in 2017-2022 in the experimental field of the Field Crops Institute in the town of Chirpan. In the IASAS system the variety was tested in 2021-2022. It was approved as a new cotton variety in 2023. Selena variety was created by remote hybridization from the crossing of the allotetraploid Gossypium thurberi Tod. × Gossypium raimondii Ulbr. with Dorina variety and subsequent backcrossing with Darmi variety. Selena variety is an early and productive new cotton variety with improved fiber quality. The vegetation period was 106-111 days. In seed cotton yield of 1663 kg/ha, on average for 6 years, it surpassed the standard cultivar Chirpan-539 by 12.3%. According to the IASAS data, in seed cotton yield of 2163 kg/ha it exceeded the two standard cultivars, Chirpan-539 - by 2.2%, Avangard-264 - by 1.3%, the average standard (average of the two standards) - by 1.8%. In lint yield of 95.5 kg/ha Selena variety was equal to Avangard-264, surpassed Chirpan-539 by 2.9% and respectively the average standard - by 1.4%. Selena variety had a number of valuable technological fiber qualities and in some indicators surpassed both standard cultivars. Compared to the two standard cultivars it had better Spinning Consistency Index (SCI), greater Upper Half Mean Length and fiber strength, lower micronaire, better spectroscopy with RD difference reflection than Chirpan-539, less yellowness than Avangard-264 and better fiber whiteness. Selena variety combines better productivity with better technological fiber qualities than the standard cultivars, which defines it as a new achievement in the selection of cotton in our country. [ABSTRACT FROM AUTHOR]

Under this general name are included the symptoms caused by several phytopathogenic fungi. The negative effect on wheat plants is mainly due to the reduced photosynthesizing area and the accelerated aging of the leaves, which leads to the poor nutrition of the grain, significant losses in yield and lowering the quality of the production. This determines the great economic importance of these diseases and the need for their in-depth study. The term wheat septoria refers to diseases caused by three anamorphic fungal pathogens of the genus Septoria. The fungal pathogens involved in the leaf spotting complex include the tan spot diseases caused by Pyrenophora tritici-repentis, Cochliobolus sativus, Monographella nivalis and several species of the genus Alternaria. An important component of the integrated control of septoriosis is genetic resistance. No complete resistance has been established in wheat to Zimoseptoria tritici, Parastagonospora nodorum and Parastagonospora avenae f. sp. triticea. Over 20 major septoria tritici blotch resistance genes have been mapped. Sources of quantitative resistance that are longer lasting under field conditions have also been identified. [ABSTRACT FROM AUTHOR]

Heterosis is a method of increasing productivity and is used in many crops. In cotton, heterosis is mainly related to yield and fiber length. Two male-sterile cotton lines ms 273 and ms 274 were included in crosses with five modern varieties: Chirpan-539, Natalia, Rumi, Helius and Nelina. Heterosis manifestations were found for productivity/plant (7.4-63.8%) and fiber length in the F1 hybrids. The cultivar Chirpan-539 and Rumi variety, with high GCA for fiber length and high variances of SCA, emerged as suitable for heterosis selection of this trait. The crosses 273 × Nelina and 274 × Nelina, with the highest productivity\plant (39.5-42.1 g) and the highest heterosis (61.9-63.8%), the second one with high SCA effects, are of interest for the heterosis selection of productivity. The crosses 274 × Chirpan-539 and 274 × Natalia, with the longest fibers (28.9-29.3 mm) and heterosis (2.1-3.5%), the first one manifested high SCA effects, are of interest for the heterosis selection of fiber length. The results obtained are encouraging for the development of heterotic selection and practical use of heterosis in cotton based on male sterility. [ABSTRACT FROM AUTHOR]

The inheritance of most important economic characters, heterosis and combining ability were studied in six interspecific (G. hirsutum L. × G. barbadnese L.) and three intraspecific hybrid combinations. There were found different types of inheritance of productivity, boll weight and lint percentage and fiber length in the individual crosses. The genetic variance for productivity and fiber length was mainly non-additive, while for lint percentage it was additive. Although non-additive genetic variance prevailed for productivity and fiber length, only individual crosses showed positive heterosis, outperforming the better parent. Of the female forms, the cultivar Helius was identified as a very good general combiner for productivity. From the male forms the cultivar Ashkabat emerged as a very good general combiner for productivity, boll weight and lint percentage. The cultivars Mytra (female), Karshinski-2 and C-6037 (male) were determined as very good general combiners for fiber length. All these cultivars, with the exception of C-6037, had low SCA variances, their high GCA was mainly due to additive gene effects, and they were very suitable for synthetic selection. The cross Helius × Ashkabat was found to be most valuable for the selection of productivity because of the highest mean performance and the highest level of heterosis with high SCA effects. All intraspecific hybrids were found to be most promising for improving lint percentage. The interspecific cross combinations Mytra × C-6037, Helius × C-6037 and Mytra × Karshinski-2, having the longest fibers, the first two with high SCA effects were most valuable for fiber length improvement. [ABSTRACT FROM AUTHOR]

The aim of this research was to study the productive potential and to evaluate the fiber technological properties of the new cotton varieties Tiara and Melani, compared to the standard cultivars. These varieties were studied in competitive varietal trials conducted in 2017-2019, in the experimental field of the Field Crops Institute in Chirpan. In the IASAS system, the Tiara and Melani varieties were tested in 2019-2020. They were approved as new varieties in 2021. Both varieties were obtained by remote hybridization and belong to the Gossypium hirsutum L. species. Tiara and Melani are early and productive varieties, in terms of seed cotton yield, on average for three years, they surpassed the cultivar Chirpan-539 (standard for productivity) by 8.1% and 6.5%, respectively. According to IASAS data, in seed cotton yield, 2809 kg/ha for Tiara and 2784 kg/ha for Melani, on average for two years, they equalized with the cultivar Chirpan-539 and outperformed the cultivar Avangard-264. In terms of fiber yield (1141 kg/ha and 1066 kg/ha) Tiara variety exceeded the two standard cultivars, Melani variety surpassed the cultivar Avangard-264 and leveled with the cultivar Chirpan-539. These varieties had a number of valuable fiber technological qualities and in some respects exceeded the two standard cultivars or equalized with the Avangard-264. The Tiara variety showed better agronomic performance than the Melani variety, achieving higher fiber yield, as a result of higher lint percentage. The Melani variety had better fiber technological qualities than the Tiara variety. Compared to the standard cultivars, the Melani variety was characterized by a better spinning, consistency index (SCI), lower micronaire, greater strength and better spectroscopy with reflection of the difference RD. This variety showed a better combination of the agronomic indicators with the fiber technological qualities than the Avangard-264, a standard for fiber quality. The results obtained define the new cotton varieties as a very good combination of earliness, productivity and fiber quality. This makes them very valuable for the cotton production and breeding programs with cotton. [ABSTRACT FROM AUTHOR]

As a result of the selection for earliness, productivity and fiber quality, two new candidate cotton varieties No 457 and No 535 were obtained. The candidate variety No 457 was obtained by remote hybridization, No 535 - by intraspecific hybridization. In 2014 - 2017, both candidate varieties were included in competitive variety trials. In the IASAS (Exclusive Agency for Variety Testing, Approbation and Seed Control) they were tested in 2017 - 2018. The two candidate varieties combined productivity and high fiber quality, which make them very valuable for cotton breeding programs. The candidate variety 457 had high and stable performance by years. In seed cotton yield of 2380 kg/ha, on average for two years, it exceeded the two standards - Chirpan-539 and Avangard-264, respectively by 11.3% and 14.7%, the average standard by 13.0%. It also was superior to them in September harvest and in yield of the fiber/ha. The candidate variety 535, in the state variety testing, in seed cotton yield was inferior to Chirpan-539 variety (standard for productivity) of 3.1% and was equaled to Avangard-264. It exceeded both standards in yield of the fiber per hectare as a result of its high lint percentage. The two candidate varieties were distinguished by high fiber quality and in some respects they exceeded the two standards or were aligned with Avangard-264, the standard for fiber quality. Compared to the standard varieties, both candidate varieties had better fiber consistency (SCI) Index, greater Upper Half Mean Length, and better spectroscopy reflecting the difference RD. Candidate variety No 457 differed with a better fiber uniformity in length than the two standards, while No 535 differed with a finer and stronger fiber. Both candidate varieties are very valuable for the selection of cotton, for inclusion in crosses to improve the productivity and fiber quality of modern cotton varieties. The No 457 in 2020 was approved by the IASAS as a new cotton variety under the name Aida. [ABSTRACT FROM AUTHOR]

The aim of this study was by means of diallel analysis of fiber length of F1 cotton hybrids to establish some genetic parameters and inheritance indexes necessary for specifying the breeding strategy by this character and breeding value of parental forms. The hybrid populations of two diallel combinations, each involving 6 parental components, were studied. A half diallel crossing scheme was used including the parents and one set of F1 hybrids from direct crosses. Each diallel combination was tested in replicated trials in two consecutive years. It was found that additive and non-additive gene effects participated in the genetic control of fiber length. The main component of genetic variance was of nonadditive type (dominance and epistasis). The varieties Darmi, Mytra and Dorina, from the 1st diallel combination, and Natalia, from the 2nd diallel combination, were identified as good general combiners for this trait. [ABSTRACT FROM AUTHOR]

The aim of this research was to study the productive potential and to evaluate the technological fiber properties of the new cotton variety Anabel, compared to the standard varieties. The new variety was studied in competitive varietal trials conducted in 2014-2017 in the experimental field of the Field Crops Institute in Chirpan. In the IASAS system, the Anabel variety was tested in 2017-2018. It was approved for the new cotton variety in 2021. Anabel variety was obtained by intraspecific hybridization and belongs to the species Gossypium hirsutum L. Anabel is an early and productive variety. According to IASAS, in seed cotton yield - 2026 kg/ha, on average for two years, it was inferior by 3.1% to the cultivar Chirpan-539 - standard for productivity and was equal to the cultivar Avangard-264 - standard for fiber quality. In terms of fiber yield, it was equal to Chirpan-539 and was superior to Avangard-264, as a result of the higher lint percentage. This new variety showed a number of valuable fiber technological qualities and in some respects exceeded both standard cultivars or was equal to Avangard-264. Compared to the standard cultivars, the variety Annabel had a better fiber spinning (SCI) Index, longer fiber, lower micriner, greater strength and better spectroscopy with reflection of the RD difference. The obtained results define the new variety Anabel as a very good combination of earliness, productivity and fiber quality. This makes it very valuable for cotton production and selection programs with cotton. [ABSTRACT FROM AUTHOR]

The interaction genotype × environment and stability for most important economic traits of 31 Bulgarian and foreign cotton varieties were studied in 2016 – 2019. The years of research were used as different ecological environments. To evaluate the stability, different stability methods were used: the stability variances (σ² i, S² i ) of Shukla (1972), the ecovalence (W² i ) of Wricke (1962), the parameter YSi of Kang (1993) and the regression parameters (bi, S² di ) of Eberhart & Russel (1966) (for the seed cotton yield only). There was significant genotype × year interaction for all traits under study. Stability was found for all traits, some genotypes showed stability for two traits. According to the regression parameters (bi and S² di), regarding seed cotton yield, the varieties Helius, Trakia, possessing high productivity, Dorina and Chirpan-539 (standard variety) showed a relatively stable performence in different year conditions. The Helius variety, combining high yield and stability according to the regression and variance parameters, outlined as the most valuable for the cotton production. Viki and Denitsa varieties, high yielding, showed specific adaptation to favorable environments and they also were very valuable for implementation in the production. The Greek variety 791-169 combined high average level for the boll weight (5.5 g) and high stability. The Viki, Avangard-264, Eva and Vega varieties (boll weight 5.4-5.5 g) also showed stable performence on all stability parameters. The Viki variety emerged as the most valuable in terms of ginning out turn, combining high mean value (36.1%) and stability. The Boyana and Nelina varieties showed also stable performence (ginning out turn 35.3-35.7%). The varieties Natalia, Dorina, Perla-267 and Colorit in fiber length were comparable with the foreign ones and had stable performance by all stability methods. Given the estimates of the parameter YSi and the overall performance according to the variances σ² i , S²i and ecovalence Wi ², the varieties Eva, Natalia, Millennium, Perla-267 and Colorit combined best 1st fruiting branch height and stability, which makes them very valuable for the cotton breeding programs. [ABSTRACT FROM AUTHOR]

The aim of this research was to study the productive potential and to evaluate the fiber quality characteristics of the new cotton Aida variety. The variety was studied in competitive variety trials conducted in 2014-2017 in the experimental field of the Field Crops Institute in town of Chirpan. In the system of the IASAS (Exclusive Agency for Variety Testing, Approbation and Seed Control) the Aida variety was tested in 2017-2018. It was approved as a new cotton variety in 2019 and was certified in 2020. It was obtained by remote hybridization and backcross technology. Aida variety showed high and stable productivity during the years of testing. According to the IASAS data, in the seed cotton yield of 2380 kg/ha, on average over two years, it exceeded the two standards - Chirpan-539 and Avangard-264, respectively by 11.3% and 14.7%, the average standard - by 13.0%. It outperformed the standards in September harvest and in fiber (lint) yield. The Aida variety was distinguished by its high fiber quality, and in some fiber properties it was superior to both standards or equalized with Avangard264 variety - standard for fiber quality. Compared to the standard varieties, the Aida variety had a better fiber consistency (SCI) Index, greater Upper Half Mean Length (UHML), better uniformity in fiber length and a better spectroscopy with a reflection of the RD difference. The content of short fibers was very low. The results obtained identified the Aida variety as a very good combination of earliness, productivity and fiber quality. This outlined it as a very valuable for the cotton production and for the cotton breeding programs. [ABSTRACT FROM AUTHOR]

The genotype × environment interaction and the stability of eight cotton lines and the standard variety were studied during 2014-2017. The years of the study appeared to be as different ecological environments. The stability variances (2 i and S2 i) of Shukla (1972) and YSi index of Kang (1993) were calculated. It was found that the cotton genotypes tested interacted significantly with the environmental (year) conditions in terms of seed cotton yields, boll weigt, fiber length and lint persentage. For an effective selection of these traits, the genotypes had to be tested in different years at diverse environmental conditions and a calculation of the phenotypic stability parameters was necessary for a more precise selection. Based on Sukla’s variance stability parameters the breeding usefull stability was observed for all studed traits. Some lines were stable for more than one traits. Line 553 was found to be stable for the seed cotton yield, boll weight and lint percentage, lines 489 and 457 – for the boll weight and fiber length. These lines appeared to be very suitable for inclusion in crosses. According to Kang’s YSi index the complex breeding value (the average level of trait and stability) was found in: line 553 for the seed coton yield, boll weight, fiber length and lint percentage; line 489 for the boll weight, fiber length and lint percentage; line 535 for the seed coton yield and boll weight; line 449 for the boll weight and fiber length; line 457 for the fiber length. These lines are very suitable for the cotton breeding programs to create genotypes with a high expression and high stability of the traits. [ABSTRACT FROM AUTHOR]

Line × tester analysis of 5 Bulgarian cotton varieties used for mothers and 3 foreign ones as fathers was applied to study the inheritance of the most important economic traits and the breeding value of parental forms (G. hirsutum L.) and F1 hybrids. The trial was conducted in 2013-2014 by block method in three replicates. Different types of inheritance were observed by the productivity, boll weight and length and lint percentage of the fibre. Exhibition of heterosis was most pronounced by productivity reaching 39.1%. For all studied traits the genetic variance was mainly of non-additive type and the prognosis for selection in early segregate generations could not be good. The varieties of Bulgarian selection, Boyana and IPK Nelina had high GCA for productivity and fibre lint percentage. Their high GCA was combined with low SCA variances making them suitable for the synthetic selection. Of the foreign varieties, the Turkish Nazilli 954 had high GCA for the fibre lint percentage, the Greek Corina - for the fibre length. Because of the high SCA variances they appeared to be more suitable for the heterosis selection. [ABSTRACT FROM AUTHOR]

Тhe new brown cotton varieties Egea and Nike were achievements in a new direction in the Bulgarian cotton breeding. They belong to a new generation of varieties with naturally coloured fibre of high ecological and economic effects. The most valuable characteristic of the two new varieties was their longer fibre than that of Izabell variety approved as a standard for the coloured cotton. According to data of the Executive Agency for Variety Testing, Approbation and Seed Control, Egea variety in fiber length (modal 23.32 mm and staple 26.83 mm) surpassed the standard variety Izabell by 1.35 mm and 1.57 mm, and Nike variety was superior by 0.37 mm and 0.54 mm. As a result of the longer fiber they also are distinguished by better spinning characteristic. With these two varieties significant progress in improving the fiber quality of coloured cotton by selection has been made. By earliness, seed cotton yield, fiber lint percentage and lint yield, the varieties Egea and Nike were equal to Izabell variety or slightly superior to it. Concerning productivity they were close to the white cotton standards, seed cotton yields were only by 1.3-1.5% less than Chirpan-539 (standard for productivity), and by 0.6-0.9% than Avangard-264 (standard for fiber quality). They were inferior in fiber lint percentage and lint yield by 7.3 kg/da (8.9%) and 7.8 kg/da (9.6%) to Chirpan-539 and by 2.2% and 2.9% to Avangard-264. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the hemorheological parameters in patients with diabetes mellitus type 2 and to estimate their relationship with the cerebral and cutaneous blood flow and their responses to postural changes. The basic hemorheological constituents: hematocrit (Ht), fibrinogen (Fib), whole blood (WBV) and plasma viscosity (PV) were examined in 20 patients with diabetes mellitus type 2 and in 10 healthy age and sex matched controls. Blood flow velocity in the middle cerebral artery (MCA) was measured by transcranial Doppler monitoring at rest and during 5-min head-up tilt. Also laser Doppler-recorded tiptoe skin blood flow was investigated and venoarteriolar reflex perfusion responses to postural impact was monitored. Significant increase of Fib and WBV at shear rates of 0.0237 s-1 to 128.5 s-1 in the patients in comparison to controls was found. The postural challenge caused decrease of the cerebral blood flow velocity and increase of the resistance index (RI) in the diabetic patients. The initial mean skin perfusion values of the tiptoes and the venoarteriolar constriction response indices were significantly higher in the diabetes group. In the patients with diabetes mellitus type 2 the increased blood viscosity values were associated with impaired cerebrovascular and peripheral vascular responces. [ABSTRACT FROM AUTHOR]