Kenaf Cultivars Research Articles

Development of EST-SSR markers through de novo RNA sequencing and application for biomass productivity in kenaf (Hibiscus cannabinus L.)

Kenaf is a multipurpose crop, but a lack of genetic information hinders genetic and molecular research. In this study, we aimed to develop EST-SSR markers from mutant and wild-type cultivars, and to assess the genetic diversity of the kenaf resources. A total of 33 Gb of sequence data comprising 130,480 unigenes was assembled by de novo RNA-sequencing of six kenaf cultivars, and 5619 SSRs were identified. Tri-nucleotide motifs occurred most frequently (82.67%) followed by di-, tetra-, and penta-motifs. In total, 515 polymorphic EST-SSRs were derived by pairwise comparisons of the cultivars based on in silico analyses. Of these, 70 markers were successfully validated among six cultivars. We used the six cultivars, together with 39 kenaf accessions from worldwide to assess genetic diversity and to characterize the EST-SSRs. The number of alleles per locus ranged from 2 to 8. PIC and genetic diversity values ranged from 0.08 to 0.79 and 0.08–0.82, respectively. The phylogenetic and population structure showed that the 45 accessions could be clearly divided into three groups based on different days to flowering (DTF). Genetic differentiation among the DTF groups showed a proportionally high level of variance. Association analysis between the DTF and the markers revealed three significant associations. Furthermore, using a multiplex PCR with three markers, DTF could be perfectly discriminated. These markers will be useful in marker-assisted selection after further validation with segregating populations of kenaf.

English

English

An Improved Kenaf Cultivar 'Jangdae' with Seed Harvesting in Korea

An Improved Kenaf Cultivar 'Jangdae' with Seed Harvesting in Korea

Physiological responses and tolerance of kenaf (Hibiscus cannabinus L.) exposed to chromium

Selection of kenaf species with chromium (Cr) tolerance and exploring the physiological mechanisms involved in Cr tolerance are crucial for application of these species to phyto-remediation. In the present study, a hydroponic experiment was conducted to investigate the variation in two kenaf cultivars, K39-2 and Zhe50-3 under Cr stress. At the same Cr concentration, the tolerance index (TI) of K39-2 was higher than that of Zhe50-3, indicating that K39-2 may be more tolerant to Cr than Zhe50-3. It was also observed that high concentration of chromium was accumulated both in the shoots and the roots of Hibiscus cannabinus L. The leaves of K39-2 accumulated 4760.28mgkg−1 of dry weight under 1.50mM Cr stress, and the roots accumulated 11,958.33mgkg−1. Physiological response shows that the antioxidant enzymes’ superoxide dismutase (SOD), catalase activity (CAT) and peroxidase (POD) activities increased in the leaves and decreased in roots of the Cr-stressed plants nearly compared to the control. Moreover, the variation of antioxidant enzymes activities indicated Zhe50-3 was more vulnerable than K39-2, and the contents of the non-protein thiol pool (GSH, NPT and PCs) were higher in K39-2 than Zhe50-3 with the increased Cr concentration. Based on the observations above, it can be concluded that the well-coordinated physiological changes confer a greater Cr tolerance to K39-2 than Zhe50-3 under Cr exposure, and Hibiscus cannabinus L. has a great accumulation capacity for chromium.

Genetic Diversity of Kenaf (Hibiscus cannabinus) Evaluated by Inter-Simple Sequence Repeat (ISSR)

Understanding genetic diversity is very useful for scientific utilization for breeding. In this study, we estimated the genetic distances in a panel of 84 kenaf accessions collected from 26 countries and regions using ISSR markers. The results of UPGMA analysis showed that kenaf germplasm had abundant genetic variation, with genetic dissimilarity coefficients ranging from 0.01 to 0.62. The in-group dissimilarity coefficient (0.29) was observed in 84 kenaf accessions, and all the accessions could be divided into three groups: cultivars (L1-1), relatively wild species (L1-2 and L1-3), and wild species (the others). Further in-group analysis in group L1-1 (0.19) revealed that the kenaf cultivars could be divided into five subgroups with distinct regional characteristics. It is imperative that genes be exchanged among all kinds of tested varieties from different origins. The results provide a useful basis for kenaf germplasm research and breeding.

Nutritive Value and Fermentation Quality of the Silage of Three Kenaf (Hibiscus cannabinas L.) Cultivars at Three Different Growth Stages

This study was conducted to evaluate the nutritive value and the quality of ensiled kenaf after fermentation with three cultivars at three different times of harvesting. Experimental plot were allocated with three harvest date (Early;8/3, medium;8/15 and late;8/28) and three cultivars (Tainung-a, Everglade, Whitten). The DM (dry matter) yield increased with maturity in all three cultivars, especially in Whitten which showed the highest yield at each harvest time. The DM content in Whitten at late harvesting time was higher than other treatments (231 g kg -1 DM). The CP (crude protein) contents of the kenaf silage of all three cultivars ranged from 151 to 164 g kg -1 . Highest content of NDF (neutral detergent fiber) was observed in Everglade at medium harvesting date, but the ADF (acid detergent fiber) content was highest in Everglade at early harvesting date (p -1 DM) showed at early harvesting date than other cultivars (p -1 DM) was higher in Tainung-a at medium harvesting date (p<0.05). No significant difference was observed in ammonia-Nand butyric acid concentrations among all treatments. These results indicate that a kenaf silage could be used as fodder for ruminants. Especially, the Whitten harvested at late growing stage showed promise as a forage silage crop under Koran environments.

Evaluation of cover-cropping managements on productivity and N-utilization efficiency of kenaf (Hibiscus cannabinus L.), under different nitrogen fertilization rates and soil types

Biomass productivity, nitrogen recovery fraction and nitrogen utilization efficiency (NUE) of kenaf (Hibiscus cannabinus L.) cultivar Tainung 2 were tested, under three Lens culinaries treatments (incorporated, harvested before the sowing of the energy crop and mono-cropping) and four nitrogen dressings (0, 50, 100 and 150kgha−1), in two field experiments carried out on a fertile, clayey to loamy soil, and on a sandy soil of moderate fertility, in central Greece, over the period 2007–2009. The obtained results showed a positive response in L. culinaries cover cropping on kenaf total yield, on both experimental sites. Total dry biomass fluctuated from 16.07 to 21.46tha−1 for incorporated plots and from 13.63 to 16.55tha−1 for control treatments (relied only on applications of N-fertilization) for sandy soil, and from 14.98 to 19.28tha−1 in case of legume incorporation and from 12.34 to 16.69tha−1 for control plots, for clayey soil, respectively. The evaluated NUE was 76kgkg−1, for sandy soil, and 72kgkg−1, for clay soil. The recovery fraction escalated from 41% in control plots to 70% in plots with previous L. culinaries cultivation for sandy soil, while for clayey soil an increase of 20% was recorded, indicating a prominent effect of legume cover-cropping management.

Effects of harvest time and cultivar on yield and physical properties fibers of kenaf (Hibiscus cannabinus L.)

Kenaf (Hibiscus cannabinus L.) is an annual non wood plant which has shown great potential as an alternative source of papermaking fiber. No information is available on kenaf cultivation in south-Iran in spite of the need to replace imported long fibers through local production of alternative sources. The purpose of this research is to investigate the effect of kenaf cultivars and harvest times on component yield and fiber quality. Six cultivar of kenaf (Cubano, Niger, Cuba 2032, 9277, 7551 and 7566) were planted on May 19, 2007 in the research farm of Agronomy Department Gorgan University. The three harvest times are 85, 105 and 135 days after planting. Result showed that bast yield, stem yield, bast: stem ratio and total dry matter, were affected by harvest time. Bast to stem ratio in second harvest time was more than any other times (40.02). Niger cultivar was the best cultivar for stem yield, bast yield and total dry material, also Cubana 2032 and Cubano were the best cultivar for bast to stem ratio with 40.41 and 40.00% respectively. Fiber morphology results showed that interaction between cultivar and harvest time was significant. The bast fiber length increased with plant age in all cultivars except Cuba 2032. Although core fiber length increased with age in 7551, 7566, 9277 and Cuba 2032 cultivars but it decreased, in Niger and Cubano cultivars. The result indicated that kenaf bast fiber were long and slender, while the core fiber were much shorter and wider. Morphology analysis indicated that bast and core fibers were significantly different. The bast fiber dimension was better than the core in the production of quality paper. Key words: Hibiscus cannabinus, kenaf, harvest time, cultivar, yield, fiber morphology.

Changes in photosynthetic rate, water potential, and proline content in kenaf seedlings under salt stress

Jin, C.-W., Sun, Y.-L. and Cho, D.-H. 2012. Changes in photosynthetic rate, water potential, and proline content in kenaf seedlings under salt stress. Can. J. Plant Sci. 92: 311-319. As irrigation water salinization has become a serious constraint for crop production, as well as soil salinity, the selection and use of salt-tolerant species is urgently required. In this study, we describe the salt responses of three kenaf (Hibiscus cannabinus L.) cultivars and select the cultivar with high salt tolerance. Responses to salt stress were investigated in terms of growth, water potentials, photosynthesis, and proline contents. Photosynthesis, evaluated by net CO2 assimilation rate, stomatal conductance, and intercellular CO2 concentration, did not show any significant effects among the cultivars. Leaf water potential decreased depending on salt concentration and salt treatment period. Proline accumulation was enhanced, particularly depending on salt concentration, but not salt treatment period. As salt concentr...

Changes in photosynthetic rate, water potential, and proline content in kenaf seedlings under salt stress

Jin, C.-W., Sun, Y.-L. and Cho, D.-H. 2012. Changes in photosynthetic rate, water potential, and proline content in kenaf seedlings under salt stress. Can. J. Plant Sci. 92: 311–319. As irrigation water salinization has become a serious constraint for crop production, as well as soil salinity, the selection and use of salt-tolerant species is urgently required. In this study, we describe the salt responses of three kenaf (Hibiscus cannabinus L.) cultivars and select the cultivar with high salt tolerance. Responses to salt stress were investigated in terms of growth, water potentials, photosynthesis, and proline contents. Photosynthesis, evaluated by net CO2assimilation rate, stomatal conductance, and intercellular CO2concentration, did not show any significant effects among the cultivars. Leaf water potential decreased depending on salt concentration and salt treatment period. Proline accumulation was enhanced, particularly depending on salt concentration, but not salt treatment period. As salt concentration increased, seedling growth was inhibited to a certain extent, and the inhibition of growth depended mainly on salt concentration. At the early stage of treatment, Dowling was more tolerant to salt stress than Everglade-41 and Tainung-2. Although Dowling showed a lower decrease in fresh weight, Tainung-2 always maintained a relatively high vegetative yield, even under high salt stress. Tainung-2, having greater salt adaptation, was therefore considered an ideal cultivar for popularization and farm cultivation.

Cloning and expression analysis of kenaf ( Hibiscus cannabinus L.) major lignin and cellulose biosynthesis gene sequences and polymer quantification during plant development

In order to apply state-of-the-art molecular breeding techniques in fibre crop it is necessary to have a good knowledge of major polymer biosynthesis gene sequences and their expression pattern. Polymerase chain reaction was employed to isolate sequences of the major genes for lignin and cellulose biosynthesis in a kenaf cultivar. CeSA, 4cl, c4h, cad, and ccr gene primers were designed according to their conservative regions; partial sequences of lignin and cellulose biosynthesis genes were obtained. One actin II gene sequence was also isolated from the kenaf genome as a housekeeping gene to be employed in qPCR analysis. Expression levels of genes c4h, cad and CeSA in bark and core from plants harvested at three different growth stages were evaluated. Using qPCR analyses it was found that the expression levels of the two biosynthesis lignin genes in bark tissues increased during plant growth, while a negative trend was recorded in core tissues. In both bark and core, the quantity of lignin was positively correlated to plant growth while cellulose content decreased.

Biomass production and nutrient concentration of kenaf grown on sewage sludge-amended soil

Due to increasingly strict control of wastewater treatment, the production of sewage sludge is surging and the problem of its disposal is therefore also growing. Recycling this waste as a fertilizer is an economically and environmentally attractive option. Determining the availability of macro- and micronutrients in these sludges is important if such wastes are to provide sufficient nutrients to crops while causing minimal environmental damage. A greenhouse study with two kenaf cultivars (‘Everglades 41’ and ‘Tainung 2’) was designed to evaluate the effects of sewage sludge processing mode on plant development, biomass yield, and nutrient availability. Two different processing modes of sludges (digested dewatered and pelletized-heat dried) applied at two rates, 10 and 20 Mg ha-1 were compared with inorganic N and a zero-N control. Plant height, basal stems diameter and biomass production increased slightly with the sewage sludge treatments but in different manners depending on the kenaf cultivar in question. Both sludges were similar in their ability to supply N to the plants. Apparent N recovery and N fertilizer equivalent value were greater in the low dosage treatments. Of the two cultivars, ‘Everglades 41’ showed greater mean values for all the variables studied. No differences were found in leaf P, K, Ca, Mg contents among treatments. The Zn and Cu concentrations were the only trace elements that increased in the leaf tissues with sludge application, although the values recorded were well below critical environmental thresholds.

Growth and biomass productivity of kenaf ( Hibiscus cannabinus, L.) under different agricultural inputs and management practices in central Greece

The growth and biomass productivity of kenaf ( Hibiscus cannabinus, L.) cultivars Tainung 2 and Everglades 41 were determined under three irrigation applications (low: 25%, moderate: 50% and fully: 100% of maximum evapotranspiration; ETm), four nitrogen dressings (0, 50, 100 and 150 kg ha −1), two sowing dates, and two plant densities (20 and 30 pl m −2) in two field experiments carried out on an representative aquic soil of western Thessaly plain (central Greece), in the period 2003–2005. The results demonstrated a paramount effect of sowing time (and thus the availability of the vegetative growing period) on crop growth and biomass productivity; delayed sowings (after mid-May) may reduce biomass production by 38%. Irrigation water had a significant effect ( P < 0.05) on growth indices and biomass productivity fluctuating upon flowering from 15.1 to 18.5 and to 20.3 t ha −1 (3-year average values) for the low, moderate and fully irrigated plants, respectively. Stems are the economic yield comprising about 87% of the total biomass in all cases. The relatively small effect of 50% irrigation to biomass production was attributed to the increased soil moisture status of the studied (aquic) soil. Contrarily, N-fertilization in the studied range did not affect significantly growth and productivity due the high fertility status of the soil, while plant population in the study range had a minor effect ( P > 0.05) on biomass accumulation. Cultivars performed similar growth rates (no significant differences), which under full water and nitrogen inputs reached maximum growth rates of 180–220 kg ha −1 day −1 which may serve as reference for the assessment of crop performance under production situations at hierarchically lower input and management levels for central Greek conditions.

Evaluation of harvesting time effects and cultivars of kenaf on papermaking

This study investigates effects of six kenaf cultivars named Cubano, Niger, Cubano 2032, 9277, 7551, and 7566 and three harvesting time stages on the properties of pulp and handsheet paper made from kenaf. Six cultivars of an Iranian kenaf (Hibiscus cannabinus L.), were planted on 19 May 2007, and harvested after 85, 105, and 135 days. It was understood that with the increase of plant age, fiber yield increased. Maximum yield at each of three harvesting time stages was related to Niger. Consequently, if a high fiber yield is sought, Niger can be recommended, but for a paper with high strength properties, Cubano 2032 is strongly suggested. This cultivar produces a paper with significant burst, tear, breaking length and fold endurance even though its yield was somewhat lower than that of Niger at short harvesting times. Moreover, at second harvesting time stage, maximum strength properties of handsheets such as burst, tear, and breaking length, were seen in Cubano, though the fiber yield of this cultivar was a bit lower than Niger, but still more than Cubano 2032. We showed that a minor positive change in the handsheet properties could be achieved through harvesting kenaf at the third stage as compared to the first and second stages.

Expression of resistance to Meloidogyne incognita in kenaf cultivars (Hibiscus cannabinus) under field conditions

Field studies were conducted in 2006 and 2007 to investigate the reaction of 10 varieties of kenaf (Hibiscus cannabinus) to natural infestation of Meloidogyne incognita. Ten weeks after planting, 10 randomly selected plants per variety were assessed for root galling. Data were also collected on plant height, stem girth, days to maturity, number of seeds and seed yield. Gall index and nematode reproduction factor varied significantly among the kenaf varieties. AU 64 recorded the tallest height of 2.4 and 2.3 m, respectively, in 2006 and 2007 cropping seasons followed by Ex-Funtua, Ifeken 100 and G 45 whereas the lowest height was recorded for Ifeken 400 and Cuba 108. Days to maturity ranged from 120 to 135 days. Based on gall index ratings, AU 64, Ex-Shika, Ex-Giwa, G45, and the local variety were susceptible to M. incognita. Tianung 1 and Cuba 108 were very susceptible, whereas Ifeken 100 and 400 were resistant. Based on reproduction factor, AU 64, Ex-Shika, Ex-Giwa, G 45, Ex-Funtua and the local variety supported greater nematode reproduction and were good hosts of root-knot nematodes. Tianung 1 and Cuba 108 were very susceptible while Ifeken 100 was a poor host of M. incognita.

The influence of environment and season on stalk yield in kenaf

Kenaf is an important fiber crop worldwide. It was recently introduced to South Africa as a commercial fiber crop. The aim of this study was to determine how different environments and seasons influence stalk yield. Nine kenaf cultivars from various countries were analysed in two environments, over two consecutive seasons, where one location was irrigated and the other not. Data were recorded for total fresh yield, defoliated stalk yield and dry stalk yield. Yield stability was analysed with four different statistical models. The dry stalk yield varied from 15.33 to 17.78 ton/ha. El Salvador and Tainung 2 had high dry stalk yields in the favourable environments, but Tainung 2 did not have stable yield across all trials. Everglades 41 and El Salvador were the most stable of the varieties across both environments and seasons. El Salvador was the cultivar that had the highest and most stable dry stalk yield in the two seasons and two locations in South Africa, and should perform well in commercial production.

Effects of Flooding on Growth, Yield and Aerenchyma Development in Adventitious Roots in Four Cultivars of Kenaf (Hibiscus cannabinus L.)

Effects of Flooding on Growth, Yield and Aerenchyma Development in Adventitious Roots in Four Cultivars of Kenaf (Hibiscus cannabinus L.)

First Report of Fusarium verticillioides on Kenaf in South Africa.

Kenaf (Malvaceae; Hibiscus cannabinus L.) is being commercially cultivated in Winterton, South Africa for its high-quality cellulose fibers with approximately 2,000 ha currently under cultivation. In 2004, 25% of 1-month-old kenaf plants grown from seed were observed in the field with severe wilting followed by lodging and mortality within 1 week. Isolations from diseased stem and root tissue on malt extract agar (MEA) consistently yielded Fusarium verticillioides (Sacc.) Nirenberg (2). Pathogenicity tests were conducted by inoculating kenaf seedlings with inoculum prepared from barley grains that had been colonized by the pathogen in vitro for 2 weeks prior to being finely ground in a laboratory mill. Fifty seeds from each of eight kenaf cultivars were incubated at 25°C on sterile filter paper to ensure germination and the absence of pathogens. Germinated seeds were sown in pots (400 cm3) containing steam sterilized loam soil (200 g) by placing 20 germinated seeds from each cultivar, with four replicates (5 seeds per pot), on the soil in each pot and covering them with 100 g of the same soil. Inoculum powder was sprinkled on the surface of the soil in each pot and covered by 100 g of soil. Pots were maintained in a glasshouse at an ambient temperature of 25°C. Sterile ground barley seeds served as the control treatment. Pots were watered daily with 20 ml of water and observed periodically for seedling emergence. The percentage of diseased seedlings was recorded after 3 weeks and the experiment was repeated. Wilting had occurred in 85% of seedlings when they were approximately 4 cm high and all diseased seedlings had died within 1 week thereafter. Subsequent examination revealed dark brown lesions girdling the stem and decayed roots in all instances. No symptoms developed on control plants. From means of combined data, the greatest seedling mortality was observed for cv. Gregg (65%) and the least for cv. Cuba108 (5%). Mean mortalities for the remaining six cultivars ranged from 30 to 55%. The pathogen was reisolated on MEA from all diseased seedlings. To our knowledge, this is the first report of F. verticillioides occurring on kenaf in South Africa. The only other report of Fusarium sp. causing serious damping-off of kenaf is from Iran (1). The potential impact of the pathogen on kenaf production in South Africa must be considered in the implementation of disease control measures.

철원지역에서 재배한 양마 (Kenaf, Hibiscus cannabinus L.)의 재식거리와 품종, 수확시기에 따른 건물수량 및 사료성분의 변화

본 연구는 양마 3품종을 재식거리, 품종 및 수확시기에 따른 건물수량과 사료성분의 변화를 검토하고자 강원도 철원지역에서 2005년 5월 20일부터 2005년 9월 12일까지 수행되었다. 시험배치는 3반복 분할구 배치로 주구는 재식거리와 수확시기를, 세구는 양마 3품종(Dowling, Everglade 및 Tainung)을 배치했으며, 결과를 요약하면 다음과 같다. 생육일수에 따른 건물 생산량은 93일까지는 재식거리가 <TEX>$10{\times}10cm^2$</TEX> 구에서 높게 나타났다. 품종별 건물생산량에서는 모든 품종이 생육시기가 진행됨에 따라 건물수량이 높아지는 경향을 보였고, 특히 Bowling이 모든 수확시기에서 가장 높은 건물생산량을 보였다. 조단백질 함량은 생육일수가 길어짐에 따라 감소하는 경향을 보였다. 특히, 생육 중기(생육일수 84일)을 기준으로 생육초기에는 조단백질 함량은 큰 차이를 나타내지 않았지만, <TEX>$10{\times}20cm^2$</TEX> 구에서 다소 높게 나타났다. 품종별로는 Bowling의 조단백질 함량이 다소 높은 것으로 조사되었으나, 큰 차이는 나타내지 않았다. 재식거리 및 품종에 따른 NDF와 ADF 함량의 차이는 조사된 3 품종 공히 생육시기가 지나감에 따라 다소 증가하는 경향을 보였지만, 큰 유의적 차이는 나타나지 않았다. 이상의 결과를 종합해 보면, 양마는 우리나라 중북부 지방에서 훌흉한 사료작물로서의 가능성이 검증되었고, 특히 Bowling 품종이 재식거리 <TEX>$10{\times}10cm^2$</TEX>로 파종하여 104일째 수확했을 때 가장 좋은 건물생산량과 품질을 보여주었다. This study was conducted to evaluate the dry matter yield and forage quality of Kenaf in relation to planting density and growing days in Cheorwon area from 20 May to 12 September in 2005. The experiment was laid out in a split plot design with three replications. The main plots consisted of planting density and growing days with three cultivars of Kenaf as sub-plots; Bowling, Everglade and Tainung. The results obtained were summarized as follows. The dry matter yield increased until 92 days after planting at <TEX>$10{\times}10cm^2$</TEX> planting density, but decreased after the day. The dry matter yield increased with maturity in all three cultivars, especially Dowling showed the highest dry matter yield at each harvest time. The Crude Protein (CP) contents of all three cultivars decreased with maturity. Especially, the decrease in the CP contents was greater in the early stage than in the late stage. The planting density did not affect the CP contents, even though they are little higher in <TEX>$10{\times}20cm^2$</TEX> planting density. The higher CP contents were obseued in Dowling, which is not significant. No difference in the Neutral detergent fiber (NDF) and Acid detergent fiber (ADF) contents was observed in the planting density and cultivar, although the increasing tendency was found with maturity. These results suggest that Kenaf can be a good potential forage crop in the northern area of Korea, especially Dowling showed the great dry matter yield and forage quality when harvested on Day 104 at <TEX>$10{\times}20cm^2$</TEX> planting density.

Factors influencing Agrobacterium mediated genetic transformation of kenaf

As a first step in the development of a successful Agrobacterium tumefaciens mediated transformation method for kenaf, factors influencing the successful T-DNA integration and expression (as measured by the GUS expression) were investigated. Transformation was carried out using two kenaf cultivars and Agrobacterium strain EHA 105 carrying different vectors, plasmid pIG 121-Hm or pEC:gus. Pre-culturing the explants for 2 days in benzyl adenine containing medium, and wounding the explant before inoculation were found to enhance the transient GUS expression. Increasing the duration of pre-culture and co-culture period enhanced the transient GUS expression up to a threshold level. Increased transient GUS expression did not correlate with an increase in stable expression. Gene integration was confirmed by PCR analysis.