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Fibers of cultivated cotton are classified into two types, lint and fuzz. Fuzzless seeds are cotton seeds lacking fuzz on almost the whole surface of the seed except for small amounts of fuzz at the micropylar or chalazal regions. Fuzzless seeds provide a number of advantages such as avoiding delintation processes and increasing the quality of feed rations. Therefore, it is important to develop varieties having seeds without fuzz but with high fiber ratios. This study, in which three different F2 populations have been developed by using three distinct genotypes as parents, was conducted to investigate the quantitative inheritance of fuzz and fiber formation and to generate a genetic mapping population. F2 populations showed 3:1 segregation for fuzz initiation and 15:1 for fiber initiation, meaning that fuzz initiation was controlled by one dominant gene while fiber initiation was controlled by two dominant genes. The ranges were between 2% and 40% for gin turnout, between 0 and 0.04 g for lint index, and between 5.5 and 15.9 g for seed index in the Stoneville 453 × PI 528429 population, while the same characters ranged from 2% to 36%, from 0 to 0.046 g, and from 9.45 to 15.42 g, respectively, for the PI 528429 × Stoneville 453 population. The last F2 population (Fiberless × Stoneville 453) showed segregation values that varied between 0% and 42% for gin turnout, between 0 and 0.045 g for lint index, and between 5.56 and 12.98 g for seed index. Additionally, there was a significant (P < 0.01) and positive correlation between gin turn out and lint index, between seed index and lint index, and between fuzz and gin turn out and lint index. These populations will provide a valuable genetic resource for fiber and fuzz initiation as well as quantitative trait locus mapping experiments.

Early sowing in cotton is important for obtaining a high and qualiy yield. Since cotton prefers high temperatures to have a good stand establisment, this work is important to determine better performing genotypes or to promote germination and emergence at low temperatures (G. hirsutumL. species (Aydin-110 and Paymaster-2379) were primed with PEG-6000 (200, 300, 400 g/L), KNO3(2, 3, 4%), KH2PO4(0.3, 0.4, 0.5 M), NaCl (2, 3, 4%) or Mannitol (2, 4, 6%) to determine the best priming medium and its best amount. After priming, seeds were germinated in germination cabin at cold (18°C) and warm (30°C) temperatures and some characteristics (germination rates, radicle length, hypocotyl length and seedling length) were analyzed. Priming with KNO3(4% or 2%) was found to result in the highest germination rates in both cotton genotypes. The seeds of the genotypes were also primed with 5-aminolevulinic acid (ALA) (1, 10, 25 mg/L), gibberellic acid (GA3) (100, 250, 500 μM), methyl jasmonate (MeJA) (1, 3, 5 μM), acetylsalicylic acid (ASA) (1, 10, 100 μM) or kinetin (1, 5, 10 mg/L) added to KNO3(4%) medium to choose the most effective plant growth regulator (PGR) application and its dose. PGRs were observed to have reverse effects on germination rate. Finally, emergence test was conducted with KNO3(4%) and KNO3(2%) using metabolic chill test, and some traits (radicle length, radicle weight, hypocotyl length, hypocotyl weight, seedling length, seedling fresh weight and seedling dry weight) were examined. Our results suggested that priming with KNO3(2%) might be an effecient way to have vigourous cotton plants under the cold stress.

Upland cotton represents the most important, and natural fiber crop in the world. Limitations in conventional breeding program for genetic improvement is due to the lack of knowledge about yield productivity and fiber quality traits. The use of molecular markers for the detection and exploitation of DNA polymorphism is one of the significant developments in the field of molecular genetics. The availability of reference genome of G. raimondii L., G. arboreum L., and next generation sequencing, routed it on the fast track for exploring the variability among genotypes of cotton. There is no molecular marker available which can fulfill all the requirements of cotton scientists. Plant breeders should utilize genomics in the breeding programs for effective selection of potential parents for certain traits. The genomic research work could use quantitative trait loci mapping, genome wide associations and next generation sequencing strategies. This review highlights the recent developments of various molecular markers for analyzing genetic diversity, constructing linkage maps and genomics tools which will assist in marker assisted selection in cotton.

Even though planting cotton early in the season is advantageous, the cold sensitivity of cotton seedlings and low germination rates, especially in the areas experiencing low temperatures, are the main obstacle for the early seasonal planting. A total of 106 genotypes from three different species; Gossypium hirsutum L., G. barbadense L., and G. herbaceum L. were screened for cold tolerance using three different approaches. Furthermore, the best screening method to differentiate between the genotypes for cold tolerance, and to predict their field emergence rates was also determined. In detail, optimal germination percentages were measured at 30 °C with the results ranging from 61% to 99%. On the other hand, cold temperature germination rates and emergence percentages ranged from 8% to 82% in paper test and from 8% to 88% (the 7th day after planting) in sand test at 18 °C, and field emergence percentages ranged from 44% to 77% at 28 days after planting. A significant difference between cotton species in terms of their tolerance to cold was observed. That is, G. barbadense genotypes had higher germination rates than the other two species in the three methods used. There was no correlation between optimal germination rates and field emergence percentages. Among cold temperature germination methods, the 18 °C paper test was better in predicting of field emergence percentage, in differentiating between genotypes in terms of their cold tolerance and in determining seed vigor. G. hirsutum cultivars; 8106-2, AYDIN-110, CORINA, DP-388, DPL-50, DPL-5614, NAZILLI-342 and one G. barbadense cultivar, GIZA 70 were more cold tolerant among all the cotton cultivars screened in this study.

We investigated in vitro regeneration ability of Prunus microcarpa subsp. tortusa using various explants (root, cotyledon and hypocotyl pieces) and cytokinins [benzyladenine (BA), meta-Topolin (mT) and thidiazuron (TDZ)]. Sectioned cotyledon, root and hypocotyl pieces of in vitro grown seedlings were cultured on Nas and Read Medium (NRM) containing BA (7.5, 10, 12.5, 15 or 17.5 mu M), mT (2.5, 5.0, 7.5, 10 or 12.5 mu M) or TDZ (2.5, 5.0, 7.5, 10 or 12.5 mu M). As a measurement of morphogenetic reaction, the ratios of regenerating explants and the numbers of primary adventitious shoots per regenerating explant were analyzed. Cotyledon explants exhibited higher regeneration ratios than hypocotyl explants, and the root explants were inappropriate for regeneration. Both BA and mT were effective on shoot regeneration but higher regenerating explant ratios were obtained when BA was used. In comparison with BA and mT, the effect of TDZ on enhancing explant regeneration ability was insignificant. Mean number of adventitious shoot per regenerating explant was between 1 and 4, and regenerating explant ratios were between 0% and 77%. The practical appliacations of the results are discussed. (C) 2010 Elsevier B.V. All rights reserved.

Combining ability and heterosis for fiber quality traits in cotton Combining ability analysis and heterosis for cotton fiber quality traits were studied in a set of diallel crosses involving eight cotton (Gossypium sp.) genotypes. Randomized complete block design was used to test 56 F1 and 8 parents for fiber quality traits; length (Len), strength (Str), micronaire (Mic), uniformity (Unf), elongation (Elg), spinning consistency index (Sci) and short fiber index (Sfi). Analysis revealed significant general combining ability (GCA) and specific combining ability (SCA) effects for all the traits and additive gene effects were important in the inheritance of the traits. Giza-45 had the highest GCA effects for Len, Sci, Unf and Elg while Is-4 had the highest Str value. Mic and Sfi values were lowest for Askabat-100 and Giza-45, respectively. The cross Cukurova-1518 × 108-F and Nazilli-84S × Askabat-100 had the lowest SCA effects for Mic and Sfi, respectively. The highest values for Len (Askabat-100 × 108-F), for Str (Acala Prema × 108-F), for Sci (Is-4 × Giza-45), for Unf (Stoneville-453 × Askabat-100) and for Elg (108-F × Is-4) were also obtained. Hybridizations among Askabat-100 × Nazilli-84S, Is-4 × Giza-45, Askabat-100 × Stoneville-453, Askabat-100 × Giza-45, Is-4 × 108F, Giza-45 × 108F, Giza-45 × Acala Prema, Nazilli-84S × Giza-45, Is-4 × Nazilli-84S and Acala Prema × Askabat-100 crosses yielded the best heterosis and heterobeltiosis values. Aforementioned parents and crosses could be utilized for further selection of high fiber quality and applying 3-way crosses or modified backcross or recurrent selection to genotypes having good combining ability would improve fiber quality.

Seed quality is one of the important objectives in cotton production and breeding. Seed-coat fragments (SCFs) and motes are the main impurities in lint cotton and are major concerns in the textile industry. A 2-year study was conducted to compare 10 cotton ( Gossypium hirsutum L.) cultivars for the number of SCFs, motes, and resistance to loading force (RL). Although cultivars were not significantly different for the number of SCFs in both years, mean values changed among cultivars and between years. Heritability for the number of SCFs was 0.52 indicating almost equal genotypic and environmental effects on phenotype. There was no correlation between the number of SCFs and RL. Cultivars were different for number of motes. Genotypic and environmental effects on the number of motes were 0.71 and 0.29, respectively. No significant correlation was detected between number of SCFs and RL.

Motes are cotton (Gossypium spp.) ovules that fail to ripen into mature seeds. These aborted ovules represent a loss in yield and can cause imperfections in yarn and cloth quality. The present study was conducted to determine whether 10 widely grown cotton cultivars differ in some boll characters that are undesirable for the textile industry. The bolls at the first positions of fruiting branches formed at 1st (bottom), 6th (middle) and 11th (top) nodes of the main stem were compared in 10 varieties in 2 years for the number of motes and their weights, mote production frequency, and long fibre mote frequency within a boll.Mote frequencies and mote weights were affected by varieties and years. Moreover, mote frequencies were higher at the bottom and middle plant positions compared with the top position.Fibre length for long fibre motes ranged from 18 to 21 mm. In both years, cultivars Deltaopal, Sayar 314 and Suregrow 125 had consistently lower mote and long fibre mote frequencies. Thus, these cultivars could be useful in breeding programmes to improve seed-set. Cotton breeders also need to consider long fibre motes in plant improvement studies.

Cotton quality and yield are affected by several factors during the growing season. A soil inhabiting fungus, Verticillium dahliae Kleb., can cause substantial yield loss in cotton. A molecular mapping F2 population derived from the interspecific cross of the highly tolerant Gossypium barbadense cv. Pima S-7 and the susceptible G. hirsutum cv. Acala 44 was phenotyped for disease incidence and severity. Phenotyping of individual plant reactions to the disease was quantified using a set of growth parameters measured 3 weeks after inoculation. The F2 phenotypic distribution of these parameters (number of healthy leaves, node number, leaf weight, stem weight, and total shoot weight) suggested that resistance is polygenic inherited. Microsatellites were used to reveal polymorphism between resistant and susceptible parents. A total of 255 simple sequence repeat (SSR) primer pairs were screened over bulks constituted by 10 resistant and 10 susceptible progeny. Sixty markers were used to analyze quantitative trait loci (QTLs). Eleven linkage groups were constructed consisting of 35 markers and spanning 531 cM with an average distance of 15.17 cM. QTL analysis was performed with MapQTL and QTL Cartographer. MapQTL indicated that 15 markers have significant linkage associations and 9 were distributed to chromosomes 10, 11, 12, and 25. Interval mapping also indicated the most likely position of markers that are significant and located on linkage groups. Three loci (CM12, STS1, 3147-2) had large effect on resistance to Verticillium wilt. Two loci were located on LG-1 and one on LG-2 and both linkage groups are located on chromosome 11. # 2005 Elsevier Ireland Ltd. All rights reserved.

Four Verticillium dahliae isolates (V76, TS-2, PH, and V44) were used in screening four cotton cultivars (Pima S-7, Acala Prema, M-315 and Acala 44). Pima S-7 and Acala Prema gave the highest resistance reactions and Acala 44 was the most susceptible. Isolate V76 of V. dahliae was the most virulent. An interspecific cross between the resistant cv Pima S-7 (Gossypium barbadense) and the susceptible cv. Acala 44 (G. hirsutum) was made and the F 2 population pheno-typed for Verticillium wilt effect. Phenotyping of plant reaction to the disease was quantified by using a set of six growth parameters (number of healthy leaves, number of nodes, leaf weight, stem weight, leaf to stem ratio, and total shoot weight) measured 3 weeks after inoculation. The F 2 phenotypic distribution of these parameters suggests that distribution is towards resistance and polygenic. Transgressive segregation also was observed. The number of healthy leaves and total shoot weight were found to be the best indicators of resistance. Results obtained in this study will be useful to quantify resistance to V. dahliae and identify the best parameters to phenotype in genetic studies.

Culture medium development methods are time-consuming, laborious, and require a large amount of experimental materials. The Nas hypothesis for the development of a micropropagation medium offers a less time-consuming and a less laborious approach. According to this hypothesis, the composition of a culture medium for a particular species should resemble the seed composition. In accordance with this hypothesis, first, an almond culture medium [Nas Almond Medium (NAM)] was developed based on almond kernel composition. Then, using mature tissues of almond cultivars, the growth of cultures on NAM was compared to that on Murashige and Skoog medium (MS), Woody Plant Medium (WPM), Driver and Kuniyuki medium (DKW), and Nas and Read medium (NRM). Medium composition had profound effects on the 3 growth parameters of number of shoots per explant, mean shoot length, and the productivity. With respect to mean number of shoots and mean shoot length, NAM was the best medium. NAM was also the most productive medium. NAM was up to 35%, 49%, 68%, and 69% more productive than NRM, MS, DKW, and WPM, respectively. The results suggest that formulating the composition of a culture medium based on the seed content can be a straightforward universal method of medium development for micropropagation.

The increase in the population at the global level necessitates to explore promising approaches to increase food supply, including protein and oil, to meet the needs of the people. Cotton is one of the most important oil producing crops and cottonseed meal provides important protein nutrients as animal feed. However, information on the genetic basis of cottonseed oil and protein contents is lacking. In this study; protein contents, oil and fatty acid composition of 124 cotton genotypes were observed for developing new cultivars. Accelerated Solvent Extraction method used for determining fat ratio; Gas Chromatography employed for fatty acid analysis while protein contents were analyzed by Kjeldahl method. Average crude oil 31.0%, total fat contents varied from 23.11 to 37.70% while mean protein content 38.0% were observed among genotypes. The dominating fatty acids included linoleic acid, palmitic acid and oleic acid (46.91, 25.73 and 20.21%) respectively, while linolenic acid (0.13%), r-linolenic (0.33%), palmitoleic acid (0.64%), myristic acid (0.88%), nervonic acid (1%) and stearic acid (2.38%) had variations in fatty acid contents. Frequency distribution of the parameters showed a normal distribution and differences among genotypes for the traits studied were statistically highly significant. Prinicipal component analysis showed a complex opposite relationship with a total protein and oil contents. Genotypes; Fantom for protein, Cirpan 60 for total crude oil, Stoneville 468 and YB195 for higher amount of fatty acids especially oleic acid; can be used for improvement of cottonseed quality in breeding programs.

Prunus microcarpa C.A. Mey. subsp. tortusa is a deciduous shrub well adapted to severe winter and dry-hot summer conditions. As the first step to explore the genetic and horticultural potential of P. microcarpa C.A. Mey. subsp. tortusa , we used SSRs to elucidate the genetic variation within its populations dispersed in upper Mesopotamia. We also investigated its phylogenetic relationship with economically important Prunus species; almond, apricot, sweet cherry, peach and plums. Using 47 amplifying SSR primer pairs, 63 P. microcarpa C.A. Mey. subsp. tortusa genotypes sampled from five locations and 15 cultivars belonging to other Prunus species were assayed. The cross-species transportability of SSRs was 96% indicating a high degree of homology between P. microcarpa C.A. Mey. subsp. tortusa and the other Prunus species. The genetic distance between P. microcarpa C.A. Mey. subsp. tortusa genotypes belonging to a particular geographic site was lower than that between genotypes of different geographic origins. Cluster analysis differentiated P. microcarpa C.A. Mey. subsp. tortusa genotypes according to their geographic sites and separated them from the other Prunus species. P. microcarpa C.A. Mey. subsp. tortusa and sweet cherry, the subgenus Cerasus , were located in the same major cluster, the other Prunus species, belonging to the subgenera Amygdalus and Prunus , were located in another one. The analysis of molecular variance (AMOVA) revealed that genetic variation among individuals within populations (59.10%) was much higher than among Prunus groups (29.28%) and among P. microcarpa C.A. Mey. subsp. tortusa populations of different geographic sites (11.61%). The results indicate a substantial genetic diversity in P. microcarpa C.A. Mey. subsp. tortusa and the need of exploring a wider area to increase the chance of finding a particular genotype.

Diallel analysis has been used in many breeding programs to increase yield and quality. Eight cotton genotypes (Giza-45, Aşkabat-100, Is-4, 108-F, Acala Prema, Çukurova-1518, Nazilli-84S, Stoneville-45) were crossed in a complete diallel design in Kahramanmaraş in 2007. Genetic characteristics for fiber quality traits; length (Len), strength (Str), micronaire (Mic), uniformity (Unf), elongation (Elg), spinning consistency index (Sci) and short fiber index (Sfi) were determined through Hayman-Jinks diallel analysis methods. The analysis of variance revealed significant differences among the parents. Inheritances of most of the characters were due to dominant genes that were determined for Len, Mic, Sci, Str in Is-4; for Sfi and Unf in Giza-45 and for Elg in Nazilli 84S.Key Words: Fiber quality, gene action, cotton, diallel Pamukta Lif Özelliklerinin Genetik Analizi Özet: Diallel analiz yöntemi verim ve kaliteyi artırmak için birçok ıslah programında kullanılmaktadır. Sekiz pamuk genotipi (Giza-45, Aşkabat-100, Is-4, 108-F, Acala Prema, Çukurova-1518, Nazilli-84S, Stoneville-45) 2007 yılında Kahramanmaraş’ta tam diallel dizayna uygun olarak melezlenmiştir. Lif kalite karakterleri; uzunluk (Len), dayanıklılık (Str), incelik (Mic), üniformite (Unf), uzama (Elg), iplik olabilirlik indeksi (Sci) ve kısa lif indeksi (Sfi) için genetik özellikler Hayman-Jinks diallel analiz yöntemine göre belirlenmiştir. Varyans analizi ebeveynler arasında önemli farklılıklar ortaya çıkartmıştır. Is-4’te Len, Mic, Sci, Str için; Giza-45’te Sfi ve Unf için; Nazilli 84S’de Elg için dominant genler belirlenmiştir.Anahtar Kelimeler: Lif kalitesi, gen hareketi, pamuk, diallel, Diallel analiz yöntemi verim ve kaliteyi artırmak için birçok ıslah programında kullanılmaktadır. Sekiz pamukgenotipi (Giza-45, Aşkabat-100, Is-4, 108-F, Acala Prema, Çukurova-1518, Nazilli-84S, Stoneville-45) 2007 yılındaKahramanmaraş’ta tam diallel dizayna uygun olarak melezlenmiştir. Lif kalite karakterleri; uzunluk (Len),dayanıklılık (Str), incelik (Mic), üniformite (Unf), uzama (Elg), iplik olabilirlik indeksi (Sci) ve kısa lif indeksi (Sfi)için genetik özellikler Hayman-Jinks diallel analiz yöntemine göre belirlenmiştir. Varyans analizi ebeveynlerarasında önemli farklılıklar ortaya çıkartmıştır. Is-4’te Len, Mic, Sci, Str için; Giza-45’te Sfi ve Unf için; Nazilli84S’de Elg için dominant genler belirlenmiştir.