Integration of trichoderma pseudokoningii with agrochemicals for disease management and plant development in mulberry

Vegetative propagation of mulberry (Morus spp.) is greatly afflicted by soilborne diseases. Stem canker (Botryodiplodia theobromae) and cutting rot (Fusarium solani) are the major diseases which cause high rate of mortality of stem‐cuttings (vegetative clones), thus affecting the initial establishment of mulberry. Apart from diseases, the poor rooting ability of stem‐cuttings of many promising mulberry varieties also leads to unproductive propagation. An effective biocontrol agent (Trichoderma pseudokoningii), chemical fungicide (Dithane M‐45) and phytohormones (Indole‐3‐acetic acid, IAA and 1‐Naphthalene acetic acid, NAA) were evaluated individually and in combination for their effects on disease control and plant development. In plates, T. pseudokoningii was found to be compatible with Dithane M‐45 at 0.1%, and IAA and NAA at 20 ppm concentrations. Under field conditions, the integration of soil application of T. pseudokoningii (in the form of its formulated product, ‘NURSERY‐GUARD') and dipping of stem‐cuttings in 0.1% solution of Dithane M‐45, or 20 ppm solution of IAA showed better results than their individual application. NURSERY‐GUARD with Dithane M‐45 (0.1%) or IAA (20 ppm) provided 47.6 to 52.4% disease control to stem‐cuttings which resulted in significant increase (over check) in sprouting of stem‐cuttings (53.1–63.3%) and plant survival (52.6–57.8%).     

Influence of source of organics and soil organic matter content on cyanobacterial nitrogen fixation and distributional pattern under different water regimes

Organic substances viz., sewage and slurry, compost, farmyard manure (FYM) and green manure used in the study under different moisture regimes had a varied effect on cyanobacterial nitrogenase activity and its distributional pattern. Green manure source was the most effective in enhancing cyanobacterial nitrogenase activity, followed by FYM, compost and sewage and slurry. A better response was observed in soils under waterlogged than under moist conditions. A gradual increase in nitrogenase activity was recorded up to one per cent organic carbon both in vitro and in vivo. The cyanobacterial diversity was maximum in sewage and slurry sites.     

Advances in mulberry tissue culture

The mulberry (Morus spp.) is an important tree in the sericultural industry because its leaves constitute the sole source of food for the Mori silkworm (Bombyx mori). Qualitative and quantitative improvements in mulberry varieties play a vital role in industrial advances. However, the perennial nature of the plants, coupled with the species prolonged juvenile period, slows this process. Plant tissue-culture techniques have been used extensively for stock improvement During the last thirty years, several researchers have reported success in plant regeneration from different expiants types. This review describes the major findings in mulberry tissue-culture research.     

SEM studies on the leaf surface of promising mulberry (Morus spp.) genotypes

Mulberry (Moms spp.) leaf quality has a great role in silkworm rearing which in turn affects the overall silk yield. In the recent past, many varieties of mulberry have been evolved considering the morphological characters, growth, yield, and quality parameters based on bioassay. The present investigation was carried out on ten promising mulberry genotypesviz. Tr-10, K-2, S-36, S-54, S-1, V-1, Mysore local, S-13, S-34, and RFS-135 to characterize stomatal size and frequency, trichomes and idioblasts using SEM. These new parameters will provide useful information for cultivars identification as well as for selecting mulberry genotypes adapted to different eco-climatic conditions and assessing the feeding quality of leaf for silkworm rearing.     

Contrasting Effects of Farmyard Manure (FYM) and Compost for Remediation of Metal Contaminated Soil

We investigated effect of farm yard manure (FYM) and compost applied to metal contaminated soil at rate of 1% (FYM-1, compost-1), 2% (FYM-2, compost-2), and 3% (FYM-3, compost-3). FYM significantly (P < 0.001) increased dry weights of shoots and roots while compost increased root dry weight compared to control. Amendments significantly increased nickel (Ni) in shoots and roots of maize except compost applied at 1%. FYM-3 and -1 caused maximum Ni in shoots (11.42 mg kg^?1) and roots (80.92 mg kg^?1), respectively while compost-2 caused maximum Ni (14.08 mg kg^?1) and (163.87 mg kg^?1) in shoots and roots, respectively. Plants grown in pots amended with FYM-2 and compost-1 contained minimum Cu (30.12 and 30.11 mg kg^?1) in shoots, respectively. FYM-2 and compost-2 caused minimum zinc (Zn) (59.08 and 66.0 mg kg^?1) in maize shoots, respectively. FYM-2 caused minimum Mn in maize shoots while compost increased Mn in shoots and roots compared to control. FYM and compost increased the ammonium bicarbonate diethylene triamine penta acetic acid (AB-DTPA) extractable Ni and Mn in the soil and decreased Cu and Zn. Lower remediation factors for all metals with compost indicated that compost was effective to stabilize the metals in soil compared to FYM.     

Biocoenology and control of whiteflies in sericulture

Abstract The damage caused by the whiteflies Dialeuropora decempuncta (Quaintance & Baker, 1913), Aleurodicus dispersus Russell, and Aleuroclava sp. to mulberry plants is extensive and they cause a huge economic loss to mulberry leaves which affects silkworm rearing. Dialeuropora decempuncta is a major pest in western Bengal, whereas spiralling whitefly A. dispersus has been reported to attack mulberry plants in South India. The whiteflies are present throughout the year in south India, with high populations in summer (March—June) and low ones in winter (October—January). The population is positively correlated with temperature and negatively correlated with humidity. Chemical control is the quick solution to minimize the pest population. However, the indiscriminate and large-scale use of highly poisonous synthetic chemical pesticides has resulted in ecological imbalance, in addition to their toxic effects on living organisms, including human beings. Hence there is a need for developing methods and materials within an eco-friendly atmosphere. Previous investigations indicate that neem-based insecticides may be a suitable alternative for pest management in sericulture. Use of neem products in sericultural pest control has many merits. It will also help in the successful introduction of biological controls in India. Several exotic parasitoids have been found to be highly effective, including two aphelinid parasitoids Encarsia haitiensis Dozier and E. meritoria Gahan. These are most promising and are reported to minimize the fly pest population. The parasitization potential and behaviour of the parasitoids have to be carefully assessed before they are introduced to control fly pest populations. There is a need for careful assessment of all these advanced biological technologies in order to develop a profitable, safe and durable approach for whitefly control in sericulture.     

Efficacy of water hyacinth compost in nursery ponds for larval rearing of Indian major carp,Labeo rohita

The use of water hyacinth compost as manure in nursery ponds for larval rearing of Indian major carp, Labeo rohita was studied. Better performance with regard to growth and survivability of the larvae was recorded in the ponds treated with water hyacinth compost (Group A) than in either the ponds treated with inorganic fertilizers (Group B) or the ponds where no treatment was applied (Group C). The average percentages of survival in Groups A, B and C were 14.3, 11.2 and 5.0, respectively. Thus about 186% increase in the survivability was recorded in the ponds treated with water hyacinth compost (P < 0.01), whereas the increase was about 124% in the ponds treated with only inorganic fertilizers, when compared with the ponds which were without any treatment.     

DECISION TOOLS FOR MULBERRY THRIPS PSEUDODENDROTHRIPS MORI （NIWA, 1908） MANAGEMENT IN SERICULTURAL REGIONS; AN OVERVIEW

Mulberry thrips Pseudodendrothrips mori (Niwa, 1908) is a major pest of mulberry trees recorded from different sericultural regions of the world. The thrips infestation affects the qualitative and quantitative characters of mulberry leaf, by direct feeding damage to leaves and the ingestion of sap, which in turn affects the silkworm cocoon crop. This is most harmful in dry climates and seasons when heavily attacked plants lose moisture heavily. Under these conditions infestation can seriously deplete yields. The seasonal population fluctuation and the degree of damage caused to the host plant are influenced by various environmental factors including climate, host-plant variety, topography, soil type, and management regimes.This article attempts to review all available documents on mulberry thrips and to discuss the practical approaches for best control of this pest.     

DECISION TOOLS FOR MULBERRY THRIPS PSEUDODENDROTHRIPS MORI (NIWA, 1908) MANAGEMENT IN SERICULTURAL REGIONS; AN OVERVIEW

Abstract Mulberry thrips Pseudodendrothrips mori (Niwa, 1908) is a major pest of mulberry trees recorded from different sericultural regions of the world. The thrips infestation affects the qualitative and quantitative characters of mulberry leaf, by direct feeding damage to leaves and the ingestion of sap, which in turn affects the silkworm cocoon crop. This is most harmful in dry climates and seasons when heavily attacked plants lose moisture heavily. Under these conditions infestation can seriously deplete yields. The seasonal population fluctuation and the degree of damage caused to the host plant are influenced by various environmental factors including climate, host-plant variety, topography, soil type, and management regimes. This article attempts to review all available documents on mulberry thrips and to discuss the practical approaches for best control of this pest.     

Performance of polyvoltine silkworm Bombyx mori L. on different mulberry plant varieties

Five cultivated mulberry plant varieties, BSRM‐34, BSRM‐56, BSRM‐57, BSRM‐58 and BSRM‐59, were used to evaluate the effects of plant variety on larval and cocoon characteristics of mulberry silkworm Bombyx mori L. Silkworm larvae undergo their entire larval periods on leaves of mulberry varieties. Different larval characteristics of larval weight, larval length and larval breadth were measured in different growth stages. After rearing, the fifth instar larvae were transferred into a mountage (Chandraki) structure for cocoon rearing for spinning and cocoon production. The cocoons were then harvested and different cocoon characteristics like cocoon weight, shell weight and shell percentage; and other characters like pupal weight and effective rate of rearing were measured. The results showed statistically significant differences among different varieties on larval and cocoon characteristics. The highest performance was observed by feeding the variety BSRM‐34 in respect of the average weight of 10 mature larvae (40.5 g), single mature larval length (7.6 cm) and breadth (1.0 cm), single cocoon weight (1.4 g), shell weight (0.2 g) and pupal weight (1.2 g) while the average performance was recorded by feeding varieties BSRM‐57 and BSRM‐59. The poorest performance was showed by feeding the variety BSRM‐56 (in case of larval characters) and BSRM‐58 (in case of cocoon characteristics). These two varieties also showed the poorest performance for silk yield. Through comparing all the above parameters it was concluded that BSRM‐34 is the best mulberry variety and it is recommended that Bangladeshi farmers adopt that variety for better yield of silk.     

Effects of optimum doses of nitrogen,phosphorus, potassium and calcium on silkworm,Bombyx mori L., growth and yield

Silkworm rearing has been an income source for small-holding farmers in Pakistan. Over the years efforts have been made to improve silkworm quality and quantity and thus develop better prospects for increasing yield and income. Mulberry leaves Morus alba L. in a series of experiments have been supplemented with various nutrients in different doses and combinations. Relative success has been achieved in this context. In our present experiments on silkworm Bombyx mori L., we fed the larvae on mulberry leaves supplemented with different doses of N (0.2%), P (0.1%), K (0.3%) and Ca (0.1%) at 26 ± 3°C with 65 ± 5% relative humidity. The results showed better outputs in terms of food consumption (72.55 g/10 larvae), coefficient of utilization (76.45%), body weight (70.07 g/10 larvae) and body length (8.56 cm/larvae) than where simple mulberry leaves were offered. Our net gains with these production parameters have been in terms of heavier cocoons with and without pupa (2.25 and 0.69 g/cocoon), respectively.     

基于RAPD分析的中国野桑蚕和家蚕遗传多样性和系统发育关系研究

对具代表性的中国11个地区的野桑蚕Bombyx mandarina进行了随机引物扩增多态性DNA(RAPD)分析,结果表明：不同地区的野桑蚕的遗传距离较大,最大为0.465(安康-镇江),最小的也有0.209(武汉-合肥);同一地区不同个体野桑蚕的遗传距离也较大,最大为0.318,最小的为0.144。它们均远大于家蚕B.mori品种内个体间的遗传距离(最大为0.068、最小为0.015),甚至超过了家蚕品种间的遗传距离(最大为0.258、最小为0.197)。这表明中国野桑蚕是一个十分混杂的、遗传多样性非常丰富的群体。另外,在大多数情况下野桑蚕的遗传距离表现出与空间距离正相关。遗传距离和系统发育分析结果显示陕西一带的野桑蚕成分复杂,有重要的演化意义。     

沼液施用对海岸带围垦麦田土壤中小型节肢动物群落的影响

土壤节肢动物群落结构是反映土壤动物多样性及土壤质量的重要指标。沼液施用对土壤结构与肥力的改变,可能对土壤节肢动物群落的特征产生显著影响。以江苏东台海岸带连续施用沼液5年的围垦麦田为例,研究沼液不同用量(0、100、200、300 m~3/hm~2)及沼液替代(0%、33%、66%、100%)化肥对土壤中小型节肢动物群落结构的影响。结果表明:各施肥管理下麦田土壤中小型节肢动物的优势类群均为前气门亚目、甲螨亚目和弹尾目,平均分别占总捕获量的52.09%—53.33%、22.42%—23.86%和13.14%—16.51%。当沼液用量从0增加到300 m~3/hm~2时,土壤动物密度增加了94%,类群数增加约2个,优势度指数增加9.4%(P<0.05)。沼液66%替代化肥时,土壤动物密度、类群数和优势度指数最高。因此,施用沼液显著增加了土壤中小型节肢动物的密度、类群数与优势度指数。当沼液替代化肥的比例为66%时,促进效应最佳。主成分分析表明,无论单施沼液还是沼液替代化肥,弹尾目、前气门亚目与甲螨亚目的响应最为敏感,可将其作为土壤中小型节肢动物对施肥响应的指示指标。     

Hierarchical clustering of 54 races and strains of the mulberry silkworm,Bombyx mori L: Significance of biochemical parameters

Summary A detailed analysis was undertaken to test the efficacy of hierarchical agglomerative clustering (UPGMA method) in grouping the races and strains of the mulberry silkworm, Bombyx moti L., and to ascertain the importance of biochemical parameters in the clustering process. The analysis was based on data from two rearing seasons with 54 selected races/strains of different geographic origin and varying yield potentials. The results indicate that seven clusters can be realised with yield parameters alone, whereas the inclusion of biochemical parameters in clustering resulted into two broad groups: one having all the breeds with high cocoon weight and shell weight, the other having all the low-yielding silkworm strains both from India and from other countries. Further sub-grouping under these two groups highlights genetical differences associated with the differentiation of various groups of races in temperate and tropical areas as well as their significance for silkworm breeding. Estimates of all ten variables were further subjected to quick clustering and the results showed that cluster 5, constituted by 38 lowyielding strains of India, China and Europe, had the highest values of the final cluster centre for amylase and the effective rate of rearing (ERR), while clusters 1 and 4 had the highest values for invertase and alkaline phosphatase. The evolutionary aspect of the genetic channelisation of silkworm races from various countries is discussed against the background of differences in the biochemical parameters and yield variables.     

Correlation between yield and biochemical parameters in the mulberry silkworm,Bombyx mori L

A detailed study was carried out on six biochemical parameters and four yield attributes using multiple regression analysis to investigate their relationship in the mulberry silkworm,Bombyx mori. The study generated new information on the importance of digestive amylase activity for the survival of the silkworm and revealed the inability of other enzymes to affect this relationship. Data also substantiate the observations made earlier on the genetic variability of amylase in the mulberry silkworm. Analyses extend the positive role of alkaline phosphatase and invertase in the expression of the other yield traits studied and indicate the definite possibility of using biochemical markers for silkworm breeding.     

Bioaccumulation of cobalt in silkworm (Bombyx mori L.) in relation to mulberry, soil and wastewater metal concentrations

The present study was planned to evaluate Co(II) toxicity in silkworm population. The soil was irrigated using synthetic wastewater to determine the effects of pH and initial cobalt concentration in its bioaccumulation in silkworm (Bombyx mori L.) food chain. The amount of cobalt in wastewater, soil, mulberry and silkworm was determined by atomic absorption spectrophotometer (AAS) analysis. The obtained results clearly indicate that silkworm can be used as template to indicate local cobalt pollution as its body length, body weight and mortality rate was found to be strongly related to cobalt concentration. Higher the cobalt amount in mulberry leaves more the toxicity to silkworm population. At 400 mg/L Co concentration and pH 4 there was maximum deposition of Co in the soil from the synthetic effluent. However, in plants and silk worm the accumulation of Co was maximum at pH 4.5 at an initial Co concentration of 400 mg/L in the synthetic effluent. The maximum cobalt found in wastewater, soil, mulberry and silkworm was 400 ± 0.01, 273.5 ± 0.04, 42.85 ± 0.01, 36.62 ± 0.22 mg/kg, respectively.     

Mulberry improvements via plastid transformation and tissue culture engineering

The in vitro tissue culture and micropropagation studies for Morus spp., a pivotal sericulture plant, are well established. The rapid and reproducible in vitro response to plant growth regulator treatments has emerged as an essential complement of transformation studies for this plant species. A major area of study is the use of protoplast culture and fusion techniques where advantages to mulberry improvement can be applied. The advancements in genetic transformation of mulberry are reviewed, and a section on strategy for transforming plastids (chloroplasts) of mulberry is included. A role for mulberry in “molecular farming” is envisioned. The conclusions and future prospects for improvement of this economically important tree species are proposed.Key words: molecular farming, Morus spp., plastid transformation, protoplast electrofusion, sericultureThe importance of silk production is well recognized in sericulture industry that involves cultivation of host plants for silkworm rearing. India is one of the countries where sericulture is an important agro-based cottage industry involved in production of five different silk types—mori, muga, eri, tasar and oak types. This classification comes from type of host plant that act as feed for silkworm, and thus sericulture industry largely depends on the availability of host plant species. Bombyx mori (mulberry silkworm) feeds on mulberry leaves, Philosomia ricini (eri silkworm) on castor leaves, Anthraea assama (muga silkworm) on som and soalu leaves, Anthraea proylei (temperate/oak tasar silkworm) on oak leaves, and Anthraea mylitta (tropical tasar silkworm) on Terminalia leaves. A systematic and proper cultivation of novel primary and/or secondary host plants showing high yield, suitability to silkworm rearing, and resistance to different abiotic stress conditions i.e., tolerance to water stress, alkalinity and salinity are recommended for sericulture improvement.The genus Morus (commonly known as mulberry) belongs to the family Moraceae, is a group of dioecious woody trees/shrubs. Many varieties of these species are cultivated on a commercial scale in India, China, Japan and Korea for the sericulture industry.¹ In India, six species are found, namely, M. alba L., M. indica L., M. nigra L., M. atropurpurea Roxb., M. serrata Roxb. and M. laevigata Wall.² Due to higher economic return and greater employment potential, attempts are been made to increase productivity by developing high yielding mulberry varieties. At present, Mysore local, Bomaypiasbari, Kanva-2 (K2), Bilidevalaya, Kajli, Sujanpur-1 (S1), BC (2) 59, C776, RFS-175, S36 and Victory-1 are being cultivated extensively in different parts of India.     

Screening of molecular markers for NPV resistance in Bombyx mori L. (Lep., Bombycidae)

Abstract: Silkworm ( Bombyx mori L.) is one of the important economic insects. Silkworm rearing and silk industry plays an important role in China, India and other developing countries. In the long history of sericultural practice, introduction of silkworm strains with high resistance to diseases has greatly improved cocoon and silk quality and productivity. However, current silkworm breeding is mainly based on traditional method that involves high input of time and labour. In order to increase the selection efficiency and accuracy for future silkworm breeding, it is necessary to establish a molecular marker-assisted selection system. In our study, three silkworm near isogenic lines that had different resistance to nuclear polyhedrosis virus (NPV) were established by means of different hybridization methods. A total of 150 random amplified polymorphic DNA (RAPD) random primers were used to screen molecular markers. Among them, two molecular markers OPA-18₇₀₀ and OPY-11₄₀₀ were found linked to major genes resistant and susceptible to NPV, respectively. Validity of the molecular markers was proved in F2 populations.     

Identification and association of ISSR markers for thermal stress in polyvoltine silkworm <Emphasis Type="Italic">Bombyx mori</Emphasis>

Evaluation of genetic resources is an essential prerequisite for their effective utilization. In India, the tropical climate prevails in most of the sericultural belts, where temperature goes beyond the ambient during summer, adversely affecting the silkworm rearing. Although polyvoltine silkworms are poor in silk content, they are mostly tolerant to tropical conditions and diseases. With an aim to identify potential silkworm races/breeds specific to thermotolerance for their effective utilization in breeding programme, 15 selected polyvoltine silkworm races were studied for their thermotolerance behaviour. Their genomic DNA samples were analyzed for ISSR-PCR using 15 selected primers. The UPGMA analysis based on Nei and Li algorithm has clustered the 15 silkworm races into five groups and one isolate. ALSCAL multidimensional scaling has not only supported the information generated by the dendrogram, but it has made the genetic distance among races more clear and substantiating their status in terms of thermal stress where pupation rate was taken as indicator. Further, discriminant function analysis (DFA) was done with three groups of silkworms classified for thermal stress viz. susceptible, moderately tolerant and tolerant. The canonical correlation value was estimated to be 0.987 (Wilk’s λ= 0.004; χ² = 36.044, p < 0.05). DFA clearly discriminated the above three groups. Beta statistics with t value and its significance for the markers identified through stepwise multiple regression analysis (MRA) revealed a total of five bands (807₁₃₀₀, 808₃₀₀₀, 808₄₀₀₀, 834₄₀₀₀, and 834₃₀₀₀) showing correlation with pupation rate after thermal treatment. Out of them, marker 808 3000 showed maximum and highly significant correlation (r = 0.757, p < 0.001, t = 4.182) with pupation rate among the silkworm races. The identified putative markers are being used to develop DNA marker to be used in evolving thermo-tolerant silkworm breeds using marker-assisted selection programme. The text was submitted by the authors in English.     

Bromatological characterization of mulberry cultivars, Morus spp., and determination of nutritional indexes of Bombyx mori L. (Lepidoptera: Bombycidae)

The objective of this work was to assess, through consumption and utilization of natural food measurements, whether mulberry cultivars, Morus spp., could be recommended to rear the silkworm, Bombyx mori L., in a commercial scale. The mulberry cultivars Miura (standard), Korin and Tailandesa and the hybrids FM 3/3, FM 86, SK 1 and SK 4 were tested. Seventy five fifth-instar commercial hybrid larvae were individualized in gerbox? unities and maintained in a rearing room (25 ± 3oC and 80 ± 10% RH).The mulberry leaves of each of the five cultivars used to feed the silkworm larvae were submitted to bromatological analysis. The dry weight of larvae at the beginning and at the end of the fifth instar, the food consumed and the feces eliminated were recorded to determine the following indexes: relative consumption rate (RCR), relative metabolic rate (RMR), relative growth rate (RGR), approximate digestibility (AD), efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD), metabolic cost (MC). The bromatological composition analysis of mulberry leaf cultivars revealed that the hybrid SK 4 presented superior nutritional quality compared to the standard cultivar Miura, due to its higher content in crude protein and ethereal extract, and lower detergent fiber content. The hybrid SK 4 was the most adequate food to the silkworm larvae because it was ingested in small amounts, thus providing good digestibility to the larvae, low metabolic cost, good growth rate and one of the highest efficiencies in the conversion of the ingested food and ingested and digested in biomass.