Kenaf Genotypes Research Articles

Management of speargrass [<i>Imperata cylindrica (L.) Raeuschel</i>] in of southern agro-ecologies of Nigeria

Speargrass [Imperata cylindrica (L.) Raeuschel] infestation limits crop growth and yield. The effects of tillage methods, kenaf genotypes, and plant spacing patterns were studied for speargrass suppression at Eruwa (Derived Savanna) and Kishi (Southern Guinea Savanna) in 2015 and 2016. These were randomized in a Split-split plot design with three replicates. Agronomic data collected were analyzed, and the means were separated at P ≤ 0.05. Results showed that tillage enhanced weed control efficiency (10%), improved I. cylindrica suppression, and kenaf performance, relative to plant sown in no-till plots at both locations. The bast-fibre yield was higher in Ifeken DI 400 than in Ifeken 400 at Eruwa, but genotypes had similar bast-fibre yield at Kishi. Also, both genotypes had comparable I. cylindrica biomass and weed control efficiency at Kishi, while Ifeken 400 had higher weed control efficiency than Ifeken DI 400 at Eruwa, due to better suppression of I. cylindrica. The agronomic traits measured and weed control efficiency (WCE %) had a substantial inverse relationship with I. cylindrical growth at both locations. Tillage improved bast fibre yield (26 – 32%), core fibre yield (20 – 28%), and seed yield (26 – 59 %) relative to no-tilled plots. Ifeken 400 showed superior weed-suppressive traits and optimum fibre yield to Ifeken DI 400 at both locations. Tilling speargrass-infested land, with kenaf plant spacing of 50 cm × 10 cm and 50 cm × 15 cm with early canopy formation and better weed suppression are considered for an integratedspeargrass management scheme.

Genome-Wide Association Study for Agronomic Traits in Gamma-Ray-Derived Mutant Kenaf (Hibiscus cannabinus L.).

Kenaf (Hibiscus cannabinus L.), in the Malvaceae family, is an important crop for not only fiber production, but also various other industrial materials. We performed phylogenetic analysis and a genome-wide association study (GWAS) of seven agronomic traits: days to flowering, plant height, fresh weight, dry weight, flower color, stem color, and leaf shape, using 96 kenaf genotypes, including gamma-irradiation-derived mutant lines. Genotypes were determined by genotyping-by-sequencing (GBS) and a total of 49,241 single-nucleotide polymorphisms (SNPs) were used in the analysis. Days to flowering, plant height, fresh weight, and dry weight were positively correlated with each other, and stem color was also correlated with fresh weight and dry weight. The phylogenetic analysis divided the 96 lines into nine related groups within two independent groups, and the GWAS analysis detected a total of 49 SNPs for days to flowering, plant height, fresh weight, dry weight, flower color, stem color, and leaf shape with -log10(P) ≥ 4, of which 22 were located in genic regions. The detected SNPs were located in genes with homology ranging from 45% to 96% to plants of the Malvaceae and Betulaceae, and these genes were found to be involved in plant growth and development via various pathways. Our identification of SNP markers related to agronomic traits is expected to help improve the quality of selective breeding programs for kenaf.

Combining ability and gene action for yield improvement in kenaf (Hibiscus cannabinus L.) under tropical conditions through diallel mating design

Nine morphologically distinct kenaf genotypes were hybridized to produce 36 hybrids following a half diallel mating design. The combining ability and gene action of 15 yield and yield components were assessed in hybrids and their parents across two environments. Except for the mid diameter and plant height traits, there were highly significant differences (p ≤ 0.01) between the environments and the interaction of genotype and environment. Additive gene effects were considerable for the inheritance of these traits, and the expression of these additive genes was heavily influenced by the environment. Significant differences were found for all studied traits for GCA except top diameter and SCA except plant height and top diameter, implying the presence of both additive and non-additive gene action for the inheritance of the concerned characters. For all features except top diameter and number of nodes, the magnitude of GCA variation was significantly higher than that of SCA variance, indicating the additive gene's predominance. The parental lines P1, P3 and P4 were outstanding general combiners for fiber yield and yield-related parameters. Considering combining ability and genetic analysis study, the crosses P1 × P4, P1 × P9, P2 × P3, P2 × P5, P4 × P6, P4 × P7, P4 × P9, P5 × P8, and P7 × P9 were found promising for their heterotic response to higher fiber yield, stick yield, seed yield and could be for future improvement in kenaf breeding programmes.

Characterization and Genetic Diversity of Photoperiodic among Mutant Kenaf (Hibiscus Cannabinus L.) Using EST-SSR Markers

ABSTRACT Information on molecular genetic diversity among Hibiscus cannabinus L. lines is crucial for developing a new variety from the existing germplasms based on consumer demand. Based on this premise, the allelic diversity of thirty-one kenaf genotypes were assessed using polymorphic EST-SSR. From the 72 EST-SSR primers tested, 10 showed sharp and clear polymorphic bands ranging from 4 (137 to 225 bp) to 7 (182 to 382 bp) alleles with a mean value of 5.2 per primer. The Polymorphism Information Content (PIC) value ranged from 0.531 to 0.737, with a mean of 0.610, indicating that the genotypes are genetically diverse. Shannon index estimation varied from 0.982 to 1.515, whereas 0.123 to 0.405 was recorded within the groups. Genetic differentiation ranged from 0.67 to 1 alongside the average gene flow (Nm) of 0.024. The AMOVA revealed 76% variation within the population, while the population gain recorded was 24%. UPGMA dendrogram indicated the relationship and categorized the evaluated kenaf mutants into five major groups. This study revealed the existence of significant variation in kenaf mutants based on EST-microsatellites. These results could be used for future breeding programs and conservation of germplasms to enhance Hibiscus cannabinus L. genotypes.

Polysaccharides, Total Phenolic, and Flavonoid Content from Different Kenaf (Hibiscus cannabinus L.) Genotypes and Their Antioxidants and Antibacterial Properties.

Kenaf (Hibiscus cannabinus L.) is a valuable plant with a potential health benefit because of its extensive bioactive compounds. Leaf extracts of 33 kenaf genotypes were investigated for their polysaccharide, total phenolic, and flavonoid content. The antioxidant properties were evaluated by 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and ferric reducing antioxidant potential (FRAP) assays. Antimicrobial capacity was also assessed against Staphylococcus aureus and Escherichia coli using a disc diffusion assay. The polysaccharide content varied from 6.45–16.12 mg glucose per g DW. Total phenolic and flavonoid content ranged from 6.03–21.15 mg GAE/g DW and 1.55–9.24 mg RE/g DW, respectively. Similarly, varied values in the range 20.55–79.99% of inhibition by DPPH, 56.28–88.30% of inhibition by ABTS and 1.26–5.08 mmol Fe2+/g DW by FRAP assays were obtained for antioxidants of the genotype extracts. Extracts from CS4 and CS2 genotypes had the highest antioxidant activities. Kenaf leaves exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli. Strong correlation was found between antioxidant activity with polysaccharide (DPPH, r = 0.893; ABTS, r = 0.819; FRAP, r = 0.864) and total phenolic content (DPPH, r = 0.850; ABTS, r = 0.959; FRAP, r = 0.953). The results suggested that the kenaf leaves could be used as a natural antioxidants and antimicrobial in food industries.

Host suitability and differential performance parameters of cotton mealybug, Phenacoccus solenopsis for resistance in fibre crop, kenaf genotypes

Aim: To enumerate resistance in Kenaf (fibre crop) genotypes with distinct host suitability, biological performance and growth parameters of mealybug, Phenacoccus solenopsis Tinsley. Methodology: Laboratory and glasshouse experiments were conducted to assess the host suitability and resistance of genotypes on the basis of relative colonization, growth and survival in terms of establishment rate and nymphal duration of mealybug. Results: The wild accession, WHIJ 50 belonging to Hibiscus spp. and the variety JRM 3 of H. cannabinus recorded significantly lowest female establishment rate, instantaneous population increase, nymphal survival and growth index with longer nymphal duration possessing possible antixenosis- and antibiosis- mediated resistance. On the other extreme the susceptible genotype, WHIN 47 (H. acetocella) proved favourable for crawler developmental parameters. Interpretation: The level, mechanism and basis of resistance in kenaf enumerated from this study may pave the way for creating vigorous kenaf hybrids resistant to cotton mealybug.

Spatial and Temporal Effects of Kenaf (Hibiscus cannabinus L.) Cultivation on Weed Dynamics in Southern Agro-ecologies of Nigeria

Weed spectrum in Kenaf fields revealed the heterogeneous flora richness of agro-ecologies and potential weed challenges. A study was conducted in the Institute of Agricultural Research and Training (IAR&T), Obafemi Awolowo University Ibadan and other substations (Ilora, Ikenne and Kishi). The effects of varied kenaf planting dates, genotypes and locations on weed dynamics and potential weed problem was investigated. Five Kenaf genotypes (Cuba 108, Ifeken DI 400, Ifeken 100, Ifeken 400 and Tianung 2) were planted. It was a 3 x 4 x 5 factorial experiment arranged in Randomized complete block design (RCBD) with three replicates. Forty five (45) weed species were identified across seventeen (17) plant families. Weed morphology comprised of broad-leaf weeds (71.11%), grass weeds (17.78%), sedge (6.67%) and spiderwort (4.44%). Abundance of broad-leaf weeds (71.11%) mostly annual, reflected regular weed control from frequent cropping patterns and agro-ecological variations. Panicum maximum, Ageratum conyzoides, Tridax procumbens, Mitracarpus villosus, Spigelia anthelmia L. and Mimosa pudica were present in the locations. Commelina erecta, C. bengalensis, Cyperus rotundus, Cyperus esculentus and Maricus alternifolius, though scanty, they were difficult-to-control weeds. Summary of weed flora richness showed that Ibadan and Ilora had thirty one (31) weed each. This represented 68.89% of the recorded weed flora composition (45) in all locations. Kishi and Ikenne had ≤ 50% of the overall weed composition recorded. This might be due to cultural practices, weed dominance and agro-ecological variance. High percentage of broad-leaf weeds (≥60%) at all locations, might resulted to keen Kenaf-weed competition due to similarity in morphology and narrows weed control option. Cultural practices, high weed fecundity, short weed life cycle (mostly annual weeds), and wide dispersal corridor in the locations maybe implicated. Weed density and weed dry weight were similar across genotypes in all locations. Ibadan had the highest weed density with the lowest weed dry weight. Ilora and Kishi had comparable weed density. Notwithstanding, highest weed dry weight was recorded in Kishi, while the lowest was recorded in Ilora. This might be due to planting dates, weed types and differences in agro-ecologies.

Identification of differentially expressed genes and pathways in isonuclear kenaf genotypes under salt stress.

Salinity is a potential abiotic stress and globally threatens crop productivity. However, the molecular mechanisms underlying salt stress tolerance with respect to cytoplasmic effect, gene expression, and metabolism pathway under salt stress have not yet been reported in isonuclear kenaf genotypes. To fill this knowledge gap, growth, physiological, biochemical, transcriptome, and cytoplasm changes in kenaf cytoplasmic male sterile (CMS) line (P3A) and its iso-nuclear maintainer line (P3B) under 200 mM sodium chloride (NaCl) stress and control conditions were analyzed. Salt stress significantly reduced leaf soluble protein, soluble sugars, proline, chlorophyll content, antioxidant enzymatic activity, and induced oxidative damage in terms of higher MDA contents in both genotypes. The reduction of these parameters resulted in a reduced plant growth compared with control. However, P3A was relatively more tolerant to salt stress than P3B. This tolerance of P3A was further confirmed by improved physio-biochemical traits under salt stress conditions. Transcriptome analysis showed that 4256 differentially expressed genes (DEGs) between the two genotypes under salt stress were identified. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that photosynthesis, photosynthesis antenna-protein, and plant hormone signal transduction pathways might be associated with the improved NaCl stress tolerance in P3A. Conclusively, P3A cytoplasmic male sterile could be a potential salt-tolerant material for future breeding program of kenaf and can be used for phytoremediation of salt-affected soils. These data provide a valuable resource on the cytoplasmic effect of salt-responsive genes in kenaf and salt stress tolerance in kenaf.

GALUR HARAPAN KENAF ADAPTIF DI LAHAN BONOROWO, KABUPATEN LAMONGAN

<p><strong>Promising kenaf lines adaptive to flooded area in Lanongan district</strong></p><p>The objective of the trial was lo ind out the most adaptive kenaf lines for flooded area in Lanongan district with a productivity of at least 20% higher than the best control varieties. The trial was conducted at Mojoasem viliage, Larcn sub-district, Lanongan. The trial was designed as a randomized block in 3 replications. Twenty kenaf genotypes consisting of 17 kenaf new lines and 3 control varieties were tested in this experiment. Plot size and plant spacing used was 2 m x 10 m and 20 cm x 15 cm, respectively. The seeds were sown in September 1999. Parameters observed were plant height, stem diameter, frish weight and dry ibre weight. The results showed that lines He 85-9-73 , He 85-9-75. and He 583 were the most promising lines for flooded areas Lanongan with the productivity of 3.4, 3.1, and 3.0 tons dry ibre per ha.</p>

Yield stability and adaptability of kenaf (Hibiscus cannabinus L.) genotypes at different kenaf growing regions in Indonesia

Stability and adaptability analysis is a very important tool for breeders to find out the potentiality of a genotype in various environments. Twenty kenaf genotypes were evaluated in 6 locations, namely Asembagus (Situbondo Regency), Muktiharjo (Pati Regency), Sumberrejo (Bojonegoro Regency), Laren (Lamongan Regency), Wanareja (Cilacap Regency), and Sukolilo (Pati Regency). For Asembagus, Muktiharjo, and Sumberrejo testing was carried out in 2013 for 2 seasons, namely longday and shortday period, while testing in Laren, Wanareja, and Sukolilo carried out in 2014 for one season on a longday period. The study is to determine the effect of the environment on the fiber yield of kenaf genotypes and their adaptation in various environments. The results of variance analysis showed that genotypes, environment, and genotype by environment interactions had a very significant effect on the fiber yield of kenaf. The average fiber yield of kenaf ranges from 0.846 to 3.758 tons per ha. Regression coefficients and mean square of deviation from regressions differ from each other indicating that there are variations in stability and adaptability between genotypes tested.

Kenaf Morpho-physiological Variations and Response to Weed Pressure in Derived Savanna Agro-ecology of Nigeria

Kenaf response to weed pressure depends on variations in morpho-physiological traits of genotypes. A study was conducted in Ibadan (7°38’ N 3°84’ E) Nigeria in the wet seasons of 2014 and 2015 to determine the response of kenaf genotypes to weed pressure. Twelve kenaf genotypes were planted in a conventionally prepared seedbed at 50 × 20 cm, in 5 x 5 m plot and arranged in an RCBD, replicated thrice. Initial weed flora composition revealed that Panicum maximum, Tithonia diversifolia, Mithracarpus viridis, Commelina spp, Aspilia africana, Tridax procumbens and Pennisetum purpureum were predominant in the experimental site. Kenaf plant height varied significantly and ranged from 30.53 cm to 59.73 cm and 60.67 to 76.80 cm at 6 weeks after sowing (WAS) in 2014 and 2015 respectively. Variation in plant height at 10 WAS did not follow the previous growth patterns in both years of the study. Stem girth at 10 WAS ranged from 1.26 cm (V1-400-2) to 1.47 cm (A-60-282) in 2014. In subsequent year, Tianung had 1.47 cm stem girth as the thinnest, while Cuba 108 had the thickest stem (1.70 cm). Ifeken 400 (56.90 cm) and Cuba 108 (53.57 cm) had the broadest canopy width in 2014 and 2015 respectively, while A2-60-28 (44.85 cm) and V1-400-2 (41.33 cm) had narrowest canopy width in 2014 and 2015 respectively. Genotypes had comparable fibre yield, possibly due to catch-up growth from 8 to 10 WAS. Ifeken 400 (480 kg/ha) and Ifeken DI400 (550 kg/ha) had the highest seed yield in 2014 and 2015 respectively. These were similar with seed yield in other genotypes except V1-400-2 (310 kg/ha) in 2014 and AC-313 (350 kg/ha) in 2015. However, seed yield reduction across genotypes ranged from 55 – 74%, with an average of 68% in both years when compared with the seed yield potentials of genotypes. Evidently, prolonged weed competition might have accounted for the seed yield deficit recorded in the study. Invariably, pre-emergence weed control only may not suffice for weed pressure in kenaf plot when seed production is of interest to the farmers. There was significant weed interference in plots sown to kenaf genotypes with low plant height and narrow canopy width. Consequently, high weed dry weight in V1-400-2 (66.39 g/m2; 89.39 g/m2) might be responsible for seed yield penalty in both years of the study. Whereas, Ifeken DI400 had the least weed dry weight (25.93 g/m2; 26.92 g/m2) and comparable seed yield with the maximum in both years of the study. Genotypic variations in morphological and physiological traits might be responsible for responses to weed interference and crop performance. Early expression of weed suppressive traits evidently influenced genotypes-weed interaction.

Genetic diversity in some Nigerian kenaf (<i>Hibiscus cannabinus</i> L.) genotypes as assessed by agro-morphological traits and seed protein markers

Identifying and assessing genetic diversity in kenaf (Hibiscus cannabinus L.) using agromorphological markers is problematic, thus, necessitating the use of biochemical markers. Thirty five kenaf genotypes were evaluated for genetic diversity using 13 agromorphological characters and seed proteins. The field experiment was laid out in a Randomized Complete Block Design with three replications; the data were subjected to Principal Component Analysis (PCA) and Cluster Analysis (CA) to group the genotypes. The observed genetic diversity among the genotypes based on Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of seed proteins was presented in the form of a dendrogram generated by the UPGMA cluster analysis. The relative effectiveness of the two types of markers in assessing the diversity among the genotypes was investigated. The CA grouped the 35 genotypes into eight clusters; the PCA revealed that the first three principal components accounted for 66.60% of the total variation among the genotypes. Plant height, stalk height, internode distance, number of seeds/pod, basal stem diameter, number of pods/plant, pod length and seed yield/plant were identified as traits that best described the genotypes. The seed protein dendrogram, in addition to grouping the 35 genotypes into four major clusters, was able to identify duplicates within the population.Keywords: Biochemical markers, principal components analysis, dendrogram, duplicates

Polyethylene glycol induced drought stress strongly influences seed germination, root morphology and cytoplasm of different kenaf genotypes

Plants are sessile and therefore continuously confronted to drought stress. Therefore, a better understanding of different kenaf genotypes is essential. The objective of this study was to assess seed germination, root morphology and cytoplasmic effects of four types of kenaf cytoplasms i.e., C1, C2, C3, C4 under different concentration of polyethylene glycol (PEG). Results showed that seed germination was increased under 10% PEG treatment compared with control and 20% PEG treatment. Among the genotypes, the hybrids C2/992, C3/992, C4/992 resulted in better germination compared with P3B and FH992. The C2 cytoplasm had the most positive cytoplasmic effects on seed vigor at germination stage. Root growth was significantly inhibited under 10% PEG and 20% PEG at seedling stage. C3/992, P3A, and P3B had improved root growth compared with other treatments at seedling stage. Under 20% PEG conditions, C1, C2, C3, and C4 cytoplasms had inhibitory effect on root growth traits except C3 cytoplasm had a positive effect on root growth. Correlation analysis showed that hundred-grain weight (HGW) was significantly correlated to seed germination performance (P < 0.01) and root dry weight (P < 0.05) under 20% PEG conditions. In particular, the CMS line P3A was the most beneficial in terms of higher germination rate and better root morphological characteristics. This indicating that P3A had the potential to withstand under drought conditions and could be used for drought resistant breeding of three-line system of kenaf crop with heavy hundred-grain weight of restorer line.

Genotypic variability and stability of fibre yield components in kenaf (&lt;i&gt;Hibiscus cannabinus&lt;/i&gt; L.)

Multi-environment yield trials (METs) are essential to reduce the challenges of the genotypes × environment interaction (G × E) in identification of promising genotypes. Therefore, this study estimated genetic variability, broad-sense heritability (h2b), genetic advances (GA) and repeatability as well as stability of core and bast fibres yield of 33 kenaf genotypes evaluated across six locations. The varieties were grown in an experiment laid out in randomized complete block design with three replications in 2016. Mature plants were harvested, retted and dried. Core fibre (CF) and bast fibre (BF) were weighed and data collected were subjected to analysis of variance (ANOVA) separately and across locations. Genetic variances, broad-sense heritability (h2b), genetic advance (GA) and repeatability were estimated for both traits. The G × E was assessed using joint regression analysis. Highly significant variation existed for both core and bast fibre yields among the genotypes in each of the locations. Phenotypic parameters were higher than those of the genotypes for both core fibre weight (CRW) and bast fibre weight (BSW). Broad-sense heritability was 82% for CRW and 66% for BSW while GA was 53.7% and 8.8% for CRW and BSW, respectively. Combined ANOVA showed significant differences for genotypes, environments, and G × E for CRW and BSW (p&lt;0.001). Partitioning of G × E showed that only Gen × Env. (linear) was significant (P&lt;0.05). Genotypic variance was 85% of the phenotypic variance for CRW, but only 32% for BSW. Hence, environmental effect was more on the CRW than BSW. Inheritance of the CRW and BSW is genetic because of their high heritability. Genetic advance and repeatability were higher for CRW than BSW. Based on high heritability with high GA for CRW, gene action governing inheritance of CRW is additive. Both additive and non-additive gene actions are responsible for BSW because its high heritability but low GA. Progress can therefore be made in selection for CRW than BSW in kenaf improvement programmes. Linear response of genotypes on environments accounted for the major part of total variation for the two types of fibre yield. Genotypes A-60-282-15, AC-313-293, AU-2452-5A and Cuba 108 are adapted to favourable environments while AU-2452-43, AU-24526, 2QQ 171 and AU-7192 are adapted to less favourable environments both in CF and BF yields.Keywords: Bast fibre, Core fibre, Genotype, Gene action, Regression analysis, Stability

Morphological characteristics, chemical and genetic diversity of kenaf (Hibiscus cannabinusL.) genotypes

Jaihyunk Ryu, Soon-Jae Kwon, Dong-Gun Kim, Min-Kyu Lee, Jung Min Kim, Yeong Deuk Jo, Sang Hoon Kim, Sang Wook Jeong, Kyung-Yun Kang, Se Won Kim, Jin-Baek Kim, and Si-Yong Kang. J Plant Biotechnol 2017;44:416-30. https://doi.org/10.5010/JPB.2017.44.4.416

English

Kenaf seed yield depends on morpho-physiological traits between varieties, and the interaction between genotype and the environment. Studies were conducted in Ibadan, Ilora and Kisi stations of the Institute of Agricultural Research and Training (IAR&amp;T), Obafemi Awolowo University, Moor Plantation, Ibadan, Oyo State, Nigeria during 2009 and 2010 cropping seasons to determine the influence of location and genotypes on seed yield potentials in 20 kenaf genotypes. The experiment was carried out using Randomized Complete Block Design (RCBD). Result shows that, kenaf plants had tallest average capsule height in Ilora in both years, while higher numbers of capsule/plant and seed number/capsule were recorded in Kishi. There were no significant differences among all the genotypes planted irrespective of the location on seed weight/plant, 100 seed weight and seed yield/ha. Average highest capsule height was recorded in 2009 across genotypes. However, average number of capsule/plant, seed number/capsule, seed weight/plant and seed yield/ha were higher in 2010. Local kenaf had highest number of capsules (55.04) with about the least seeds per capsule (9.45) and least weight of seed per plant (3.30 g). While BS-1 had the least capsule number (18.86) and highest seeds per capsule (15.74) was recorded in SF-549. AU-75 recorded the highest seed weight/plant. The 100 seed weight ranged from 3.37 to 2.19 g. Seed yield/ha across genotypes ranged from 660 kg/ha in Local line 36 to 1454.3 kg/ha in AU-75. &nbsp; Key words: Kenaf, capsule height, capsule number, seed number, seed weight/capsule, 100 seed weight and seed yield/ha.

SIMULTANEOUS SELECTION FOR HIGH YIELDING AND STABILITY OF SOME ECONOMIC KENAF CHARACTERS

The materials used for the present study consisted of fourteen kenaf genotypes (G) which were evaluated over six environments (three at Ismailia Governorate, two at Giza Governorate and one at El-Beheira Governorate) through three successive seasons (2009 to 2011). in Egypt. The analysis of variance revealed highly significant differences among genotypes, environments and G x E interaction for all studied traits, indicating a wide range of variation among genotypes, environments and these genotypes exhibited differential response to environmental conditions. The significant variance due to residual for all characters indicated that genotypes differed with respect to their stability suggesting that prediction would be difficult, which means that mean performance alone would not be appropriate. Interaction component of variance (σ2ge) was less than the genotypic variance (σ2g) for all characters. This means that genotypes differ in their genetic potential for these traits. The observed narrow range between phenotypic and genotypic coefficients of variability with high heritability in broad since for fiber percentage . Also, fiber weight per plant, technical stem length and plant height showed similar results, indicating possibility of using these three yield traits in selection criteria with giving more weight for fiber weight per plant and technical stem length for improving green stalk yield per plant in turn fiber yield. The criterion, yield stability (YSi) statistic indicated that S.105/2 and S.113 were proved to be superior in yield and stability for all characters studied as well as three genotypes, S.96/20, Giza3 and S.8 were stable for most characters studied. Therefore, the two genotypes (S.105/2 and S.113) maintained mean performance advantage across nearly all the environments sampled by maintaining high level for the above-mentioned traits and they are recommended to be released as commercial stable high yielding cultivars and/or to be incorporated in kenaf breeding program for producing stable high yielding lines. Phenotypic correlation coefficients among green stalk weight with other related characters of kenaf, indicated that, plant height, technical stem length, and fiber percentage are the major components contributing to green stalk weight per plant. Therefore, selection for these traits will improve green stalk weight per plant and in turn fiber yield in kenaf.

Genetic diversity analysis of kenaf ( Hibiscus cannabinus L.) using AFLP (amplified fragment length polymorphism) markers

Nineteen kenaf genotypes from Cuba, Taiwan, the USA, El Salvador, Guatemala, Russia, Spain and Indonesia, and three wild types collected in South Africa were analysed for genetic diversity using AFLP analysis. All could be uniquely distinguished from one another, but only a low level of genetic diversity was present. The most distinct accession, Guatemala 4, was 85% similar to all other accessions. The accessions clustered more or less according to known pedigree and/or origin. Two of the three wild types (Hibiscus cannabinusc andH. cannabinusa) clustered separately from the commercial and Russian accessions. One of the wild types,H. cannabinusb clustered with some of the commercial accessions. Commercial accessions in the first subgroup all originated from central and North America, and surrounding islands (Cuba and El Salvador). The Russian accessions are all grouped together. The second subgroup was the only group that contained accessions from different geographical origins.

ESTIMATION OF SOME GENETIC PARAMETERS FOR YIELD AND YIELD COMPONENTS IN KENAF (HIBISCUS CANNABINUS L.)

Two field experiments were carried out at EI-Gemmiza Agric. Res. Station, Gharbia Govemorate, A.R.C., Egypt during the two successive seasons, 2005 and 2006, to study the variability and covariability for green stalk weight, fiber weight and their related characters through evaluation of fourteen kenaf genotypes in a randomized complete block design with three replications. The collected data indicated that, local strain 105/2 gave the highest mean for each of green stalk yield per fed, fiber yield per fed, green stalk weight per plant, plant height, technical stem length, fiber length, fiber weight per plant, fiber percentage, fruiting zone length, stem diameter and seed weight per plant. While, the maximum seed yield per fed was recorded by S.96/20. Mean squares due to genotypes were highly significant for all characters, revealing the variability existed among these genotypes, resulted in increasing the chance to select high yielding potential genotypes for all characters. The genotype x year variance (029y) was less than the genotypic variance (egg) for all characters except fiber percentage, indicating that most of variability in most studied characters was mainly controlled by genetic factors with less influence by environmental factors. This mean that improvement of these traits could be achieved by direct selection. The narrow range between phenotypic (PCV) and genotypic (GCV) coefficient of variability gave almost similar values, for plant height and technical stem length. Reflected the importance of selection for these traits (plant height and technical stem length), which also gave high heritability estimates. Phenotypic (re) and genotypic (re) correlation coefficients concluded that plant height, technical stem length, fiber length, green weight per plant and fiber percentage are the major components contributing to fiber weight per plant. Therefore, selection for these traits will improve the fiber yield (weight) in kenaf.

First Report of Basal Stem Rot Caused by Pythium Group G on Kenaf in South Africa.

Kenaf (Hibiscus cannabinus L. Malvaceae) presents a source of high-quality cellulose fibers and is being investigated in South Africa for commercial production. In March 2001, 12 5-month-old kenaf plants grown from seed in experimental plots near Bloemfontein, South Africa, displayed large, black, sunken lesions (10 to 20 cm long) at the base of the stem, and severe root rot. A study was undertaken to characterize the pathogen, and to determine the relative susceptibilities of five kenaf genotypes being considered for commercial cultivation. Isolations from diseased tissue on malt extract agar consistently yielded a fungus identified as Pythium group G (1). Four-month-old kenaf plants were artificially inoculated in the field by inserting wooden toothpick tips colonized by the pathogen approximately 25 cm above soil level into the stems of 10 plants of each of five genotypes. Inoculation points were wrapped using Parafilm. The fungus was highly virulent to all five kenaf genotypes in two experiments, with mean cambial lesion lengths of 117, 119, 120, 122, and 139 mm at 7 days after inoculation for Tainung-2, Cuba 108, SF-459, El Salvador, and Everglades 41, respectively. Lesions ranged from 44 to 164 mm, with an overall mean of 124 mm for all five genotypes. No lesions developed in control plants. Although Everglades had the longest lesions, there were no significant differences (P < 0.05) among genotypes. Koch's postulates were completed by reisolating the fungus from all inoculated plants. To our knowledge, there are no published reports of Pythium group G causing stem or root rot of kenaf.