JOURNAL OF ROOT CROPS

Standardization of an efficient DNA isolation protocol in tannia [Xanthosoma sagittifolium(L.) Schott]

2024-02-22T06:03:54+00:00

Genetic variability is very much limited in tannia (Xanthosoma sagittifolium(L.) Schott).Morphological
variation is limited to colour variation in leaf, petioleand tuber flesh colour in this crop. Tuber shape and
size also shows variation. ICAR-CTCRI being the National Repository for tuber crops is maintaining the
germplasm collection of edible aroids including tannia. In order to assess the genetic diversity existing in
this introduced crop, different DNA isolation protocols were tested in four tannia accessions to identity
the best method. CTAB method standardised by Sharma et al., (2008) for taro, DNeasy kit method
(Qiagen) and modified Dellaporta method were tried. It was observed that the quality of DNA was
good in the modified Dellaporta method with DNA quality ranging from 1.98 (Xa-6) to 2.23 (Xa-67).
Good quantity was obtained ranging from 830 ng/?l (ACIX-2) to 1968 ng/?l (Xa-71). The extracted
DNA was amenable to ISSR markers. Hence, for all further molecular studies in tannia, the modified
Dellaporta method was adopted.

Effect of various soil amendments on soil pH and exchangeable Ca at different depths in the identification of a suitable liming material for tannia (Xanthosoma sagittifolium L. Schott) in an Ultisol, Kerala, India

2024-02-22T04:30:36+00:00

Tannia (Xanthosoma sagittifolium L. Schott) is an important tropical tuber crop coming under the group
of aroids. It is usually grown as intercrop in plantations and fetches good remuneration. When this
crop is grown in the acid laterite soils (Ultisols), widespread occurrence of Mg deficiency was very
common resulting in the complete devastation of the crop. The reason attributed was the acidity due to
excess Al3+ions in the subsoil layers which causes the decay of roots and hence adversely affecting the
absorption of water and nutrients. This crop being an indicator plant for Mg deficiency, the symptom
is manifested as interveinal chlorosis coupled with drying of the whole plant. The present study was
undertaken to screen a better soil amendment to tackle the problem of subsoil acidity induced multi
nutrient disorder in tannia. The present study was done using five liming materials viz., calcite, dolomite,
gypsum, calcium silicate and calcium oxalate at quantities ranging from 50-1000g both under controlled
condition in lysimeter and in field. After application of treatments, soil samples drawn continuously for
6-7 months from four different depths viz., 0-15, 15-30, 30-45 and 45-60 cm were analysed for pH,
CEC and exchangeable Ca. The data generated were statistically analysed for the independent and
interaction effect of treatments (liming materials, rate of application, depth of sampling and interval
after application) and results on the mean effect, changes over initial and at the end of 6-7 months of
application with respect pH and exchangeable Ca for the above treatments were described. The results
from both situations revealed that, calcite, dolomite and gypsum were equally effective. Among the
three, dolomite being a source of both Ca and Mg, even at lower quantities as 250 g was found better
in enhancing both pH (1.54 units over initial) and exchangeable Ca (1.559 cmol (+) kg soil-1 over
initial) to the maximum extent especially at lower depths up to 60 cm to a period of 4-5 months after
application.

Study on compatibility of Trichoderma asperellum and fungicides for the development of environment friendly and cost-effective disease management strategies

2024-02-22T06:20:32+00:00

Chemical fungicides are regularly being used to combat plant pathogens successfully. The escalating
concern over human health and environmental safety often put pressure on farmers to lessen the use
of chemicals. One of the approaches to minimize the use of fungicides is to integrate it with biological
control agents (BCA). Trichoderma species are well known for their biological control activity against
many plant pathogens. Application of Trichoderma is being endorsed for the management of diseases
of tropical tuber crops viz., collar rot of elephant foot yam, tuber rot of cassava, stem and root rot of
cassava, yam anthracnose and taro leaf blight. For an effective disease management, the activity of biocontrol
agent should not be stalled by the usage of fungicides. Trichoderma asperellum has been studied
expansively as a BCA with results reliant on the specificity of the isolate. Present study was conducted
at ICAR-Central Tuber Crops Research Institute, Sreekariyam, Thiruvananthapuram to study the
sensitivity of T. asperellum isolate tovarious fungicides. Knowledge onthe compatibility of possible
bio agents with regularly used and newer agrochemicals is vital for refining/developingan efficient
integrated disease management programme. Effect of twelve fungicideson mycelial growth of Trichoderma
was tested by adopting poison food technique. Fungicides were tested at different concentrations
ranging from 3.125 ppm to 3200 ppm. The fungicides, Copper oxychloride 50%, Cymoxanil 8%+
Mancozeb 64%, Mefenoxam 4%+ Mancozeb 64% and Cymoxanil 22.1% +Famoxadone 16.6% were
compatible with T. asperellumat their recommended concentration by not inhibiting the mycelial growth.
WhereasCarbendazim 50%, Carbendazim 25% + Mancozeb 50%, Hexaconazole 5%, Difenoconazole
25% and Metalaxyl–M 3.3%+ Chlorothalonil 33.1% inhibited the mycelial growth of bioagent
indicating their incompatibility. A progressive increase in percent inhibition of radial growth in the
fungus was observed as the concentrations of fungicides increased. The results obtained from the
present study will help in revisiting integrated disease management strategies by combining bioagent,
Trichoderma and fungicides for managing fungal diseases of tropical tuber crops.

Insecticide residues in tuber crops and its effect on soil microbes

2024-02-22T06:32:32+00:00

Sucking pests are one of the most important problems in tuber crop cultivation. For the management
of sucking pests’ whitefly, mealybug, scale etc., systemic insecticides like imidacloprid and dimethoate
are recommended for drenching and spraying. In the present study, these insecticides were tested for
their impact on soil micro-organisms and for their presence in cassava.Beneficial soil microbes Bacillus
cereus, Beauveria bassiana and Trichoderma spp. were isolated from rhizosphere soil of tuber crops and their
growth in insecticide applied media were compared. Residue analysis of the plant samples (cassava leaves
and tubers) was conducted after the application of insecticides at recommended doses to the plants.
Observations were taken after 1, 7, 14 and 30 days of application. From the LC-MS and GC-MS study,
it was found that tuber (edible part) is safe from imidacloprid residue even 24 h after the application.
But, 0.051 ppm dimethoate residue was noticed in cassava tubers after 30 days of drenching with the
insecticide.

Change in climate and climate suitability of major taro [Colocasia esculenta (L.) schott] growing regions of India

2024-02-22T06:43:53+00:00

Root and tuber crops such as taro [Colocasia esculenta (L.) schott] play a vital role in food security
and livelihoods and yet neglected in climate change impact studies and large-scale crop improvement
programs. This study attempts ensembled multi-model prediction of change in climate and climate
suitability of taro in major taro growing regions of India by 2030 and 2050 under 4.5 and 8.5
representative concentration pathways (RCP). Climate, suitability (EcoCrop model) and suitability
changes were analysed using Arc GIS 10.1 and Diva GIS 7.5. According to the study, under RCPs 4.5
and 8.5, the major taro growing regions will experience warming of the climate by 2030 and 2050.
The mean temperature of major taro growing regions in 2030 will increase by 1.15- 1.49°C and 1.58 –
2.09°C for RCPs 4.5 and 8.5; and 1.35 - 1.70°C and 2.02 - 2.68°C for RCPs 4.5 and 8.5 in 2050. The
precipitation in 2030 will increase by -2.01 – 82.07 mm and 2.84 - 128.02 mm for RCPs 4.5 and 8.5;
and in 2050 it will change by 13.48 to 16.98 mm and 1.09 to 108.54 mm for RCPs 4.5 and 8.5. The
climate suitability will change by -12.31 to 5.17% and -14.29 to 7.63% in 2030 for RCPs 4.5 and 8.5;
and -18.26 to 6.57% and -24.1 to 9.39% for RCPs 4.5 and 8.5 in 2050.

SNP marker development in cassava for cassava mosaic disease resistance using bioinformatics tools

2024-02-22T08:35:15+00:00

Cassava (Manihot esculenta Crantz), originated in Latin America is one of the most important food crops
with a worldwide production of 314.81 million tonnes. The advancements in sequencing ability and less
cost involved allow for effective genome-wide discovery of SNPs. The present study was undertaken to
computationally develop SNPs for cassava mosaic disease resistance and to understand the effectiveness
of molecular markers in cassava for biotic stress response (cassava mosaic virus). The preliminary data
set for the work was obtained from the EST section of NCBI (http://www.ncbi.nlm.nih.gov/nucest).
The draft cassava genome sequence and transcript sequences (variety AM560-2, JGI annotation v4.1)
from the Phytozome website (http://phytozome.jgi.doe.gov/pz/portal.html) were also utilized. The SNP
prediction tools, viz., Quality SNP and Auto SNP were used to predictthe SNPs. Quality SNP predicted
about 56 SNPs, in which 30 were non-synonymous and 26 were synonymous SNPs. Primers were
designed for five selected SNPs associated with CMD resistant genes. These primers were validated
using 5 resistant and 5 susceptible cassava genotypes. Among the primers, after validation one SNP
(SNP896) primer was able to clearly differentiate between the resistant and susceptible genotypes. This
is the first report of SNPs computationally identified and verified in wet lab. The results showed that
the sequence with SNP1043 did not show any variation in the predicted SNP site, but SNP896 in the
variety, MNga showed SNP at the 1493th position with a variation in the base. The same SNP896 did not
show any variance in that position for the susceptible variety CI732.

Coat Protein Gene: A key tool for Yam Mild Mosaic Virus diagnosis in greater yam

2024-02-22T08:48:49+00:00

Destruction of infected plants and use of virus-free planting materials are the common control measures
used for preventing viral infections. These practices are inadequate to combat the virus attack in many
incidents. Early detection of infection is an effective way to manage the systemic primary spread of
viruses. Infection caused by Yam mild mosaic virus (YMMV), one of the major viruses in yams (Dioscorea
spp) is difficult to detect in the early stages. Symptoms include mild mosaic, leaf mottling, and chlorosis
and leaf distortion. In the present study, PCR was employed for the amplification of YMMV coat protein
(CP) gene for diagnosing the virus from greater yam (Dioscorea alata L.) leaves. The specific primer
pair was designed and validated for CP gene amplification, which yielded an amplicon of 810 bp in
YMMV positive samples. Subsequent cloning in pUC18 vector and sequencing confirmed the presence
of the full coat protein (CP). In addition to PCR-based diagnostic method, the accomplished isolation
and characterization process opens avenues for generating virus-specific polyclonal antibodies through
the utilization of the expressed coat protein. These antibodies can be further employed in serological
techniques.

Co-pigmentation of sweet potato and greater yam anthocyanins with selected phenolic acids and its effect on in vitro antioxidant activity

2024-02-22T09:10:17+00:00

The effect of co-pigmentation on the antioxidant capacity of anthocyanins isolated from purple colored
root tubers of greater yam (Dioscorea alata, Acc. Da-340) and sweet potato (Ipomoea batatas, cv Bhu
Krishna) with caffeic, ferulic and p-coumaric acids was investigated in this study. The DPPH radical
scavenging activity of both the anthocyanins enhanced significantly after co-pigmentation. However,
phenolic acids behaved differently with different concentrations of anthocyanins. Except at very low
anthocyanin concentrations, caffeic acid and ferulic acid served as effective co-pigments for greater
yam and sweet potato anthocyanins respectively, leading to an increase in antioxidant potential. At very
low concentrations of the pigment and co-pigment used, the effect was reverse. The highest % radical
scavenging activity was observed for greater yam anthocyanins at a concentration of 6 ?gml-1 and 26 ?g
ml-1 of ferulic acid as the co-pigment, followed by the same concentration of anthocyanins and 24 ?g
ml-1 of caffeic acid. P-coumaric acid was not as effective as caffeic and ferulic acids. This study indicated
the existence of some distinct intermolecular interactions that ensue in the complex framework of
natural colors and the results could beuseful in designing bioactive food colorants.

Tillage and mulching practices in cassava (Manihot esculenta Crantz): Influence on soil carbon mineralization, enzyme activity and glomalin content

2024-02-22T09:19:44+00:00

A study was undertaken in laterite soils (Ultisols) in 2017 to find out the effects of continuous adoption
of different tillage and mulching practices on carbon and nitrogen mineralization. Soil physico-chemical
properties and biological parameters viz., soil enzyme (as an indicator of soil biological activity) and
glomalin content (as an indicator of soil carbon sequestration) were estimated to find the relationships
with the mineralization rate. Surface soil samples (0-0.15 m) from five treatments involving four tillage
and mulching treatments each with three replications and a control were taken for the study. Results
showed that maximum water holding capacity (WHC) of 41.3% was found in soils under conventional
tillage with sheet mulching (T1) as compared to 37.7% in control (T5) with optimum BD (1.41 Mg
m-3) and porosity (46%). No significant differences in soil pH were observed among tillage practices.
The soil organic carbon registered a maximum value under T5 (1.37%). A significant increase of
carbon mineralization was noted in T1 (137.7 mg CO2 100 g-1 soil) followed by minimum tillage with
mulching (T3). The maximum mineralization of nitrogen, dehydrogenase activity, total glomalin (TG)
and easily extractable glomalin (EEG) were recorded with control (T5). Results indicated that adoption
of conventional tillage with porous ground cover sheet mulching practices increased soil carbon
mineralization activity to an extent of 18.2, 19.3 and 28.6% over minimum tillage with mulching at 24
h, 48 h and 7 days, respectively. Among the soil properties, conventional tillage practices increased the
soil bulk density insignificantly and the water holding capacity to an extent of 15.6% over minimum
tillage.

Evaluation of improved varieties of cassava in the tribal belts of Attappadi in Kerala

2024-02-22T09:34:54+00:00

Cassava is an important source of energy in the diet of the people of tropical countries in the world.
It has enormous potential in India for food security and industrial uses due to its ability to grow in
marginal and waste lands where other crops do not survive. Commercial planting of cassava is done
from stem cuttings. Because of the low multiplication rate as compared to cereals and pulses, the
high yielding varieties released in the research institute takes many years to reach the farmers. Over
the years, clonal multiplication degenerates the planting material, reduce tuber yield drastically, and
renders the cultivation of cassava uneconomical. An attempt was made to see the performance of
improved varieties of cassava in Pudur gram Panchayat of Attappadi tribal region in Palakkad district
which falls under Attappadi Hills laterites Agro Ecological Unit 18 (AEU18) of Kerala. The programme
was implemented under the project on Development of Tuber Crops financed by Government of
Kerala during 2014-15 and 2015-16 undertaken by ICAR-Central Tuber Crops Research Institute,
Sreekariyam, Thiruvananthapuram, Kerala. Fifty farmers were selected and quality planting materials
of improved varieties of cassava from ICAR-Central Tuber Crops Research Institute (ICAR-CTCRI),
Thiruvananthapuram, Kerala were distributed for cultivation in an area of 25 cents of each, with a total
areaof 5 ha. The cultivation of cassava was carried out under rainfed conditions with the guidance and
the direct supervision of ICAR-CTCRI scientists. Farmers got an average tuber yield of 3.40 kg to 6.50
kg per plant with an average number of tubers from 6 and 12 per plant in Pudur grama panchayat.
Improved varieties of cassava produced significantly higher average tuber yield of 59.25t ha-1 at Pudur
and the farmers also could produce 1.25 lakhs stems of cassava in one season sufficient for cultivation
in an area of 80 ha. Adoption of improved varieties was economic with a B:C ratio of 2:1 which could
improve their livelihood also, in addition to food security.

Data generation for smart hydroponic system development in Syngonium podophyllum (Arrowhead vine)

2024-02-22T10:20:23+00:00

Hydroponics, a young budding science which can be used as an alternative sustainable production
system under limited resource availability conditions. High quality ornamental plants can be produced
through hydroponics as it encourages faster growth. Arrowhead vine (Syngonium podophyllum) is a
widely cultivated ornamental foliage plant as it eliminates polluting agents from inside households. An
experiment on standardization of solution culture in Deep Flow Technique (DFT) of hydroponics in
Syngonium podophyllum was carried out at College of Agriculture, Vellayani, Thiruvananthapuram during
the year 2022. The experiment was laid out in completely randomized design. Four doses of Hoagland
solution and cooper solution (50%, 100%, 150% and 200%) were given and replicated ten times.
Data on growth parameters for development of a smart hydroponic system was collected in scheduled
intervals. The electrical conductivity (EC) and pH were monitored at weekly intervals and observations
on growth parameters were taken at every 15 days interval for four months. The treatment with 150%
Hoagland solution in Syngonium podophyllum plants showed superior characteristics for number of leaves,
leaf length, leaf breadth, plant height and plant spread. The data can be used for developing an automatic
hydroponic system controlled by a mobile application and different ornamental foliage plants can be
tested using it.

Influence of organic and inorganic fertilizers on dynamics of nitrogen, phosphorus and potassium in relation to yield and proximate composition of Colocasia

2024-02-22T10:31:51+00:00

Field experiments were conducted during 2018-2020 to study the effect of integrated use of inorganic
fertilizers and organic manure on the dynamics of nitrogen, phosphorus and potassium in relation to yield
and proximate composition of colocasia (Colocasia esculenta L) in an Alfisol. The inorganic fractions and
available nutrient contents of N, P and K were found highest due to integrated application of FYM and
½ NPK followed by application of 80-30-80 kg ha-1 of N, P and K. Sequence of occurrence of inorganic
P fractions (mg kg-1) in the soils followed the order: Reductant soluble P (42.39) > Fe-P (38.10) >
Ca-P (30.23) > Al-P (23.71) > Bray’s-1-P (17.86) > Water soluble P (2.94). Occurrence of different
K fractions (kg ha-1) was in the order: NH4OAc-K (210.05) > exchangeable-K (186.56) > nonexchangeable
K (111.54) > water soluble-K (23.49). Available N was contributed mostly by NO3-N and
total N. All the inorganic P fractions contributed significantly to the available P pool and the relationship
(r) was found to be in the order of water soluble P (0.97**) > Fe-P (0.96**) > RS-P (0.95**) > Al-P
(0.94**) > Ca-P (0.90**). However, exchangeable K and total K contributed significantly towards the
available K content of the soil. Ammoniacal N showed a highly positive and significant relationship with
corm yield and biochemical constituents of taro. Iron bound P and Al-P fractions contributed mostly
towards the P nutrition of colocasia. Of all the K fractions, non- exchangeable K has recorded higher ‘r’
values with cormel yield and bio-chemical constituents. Application of organic manure and half of the
soil test based NPK not only sustain the soil quality and enhanced the productivity of colocasia but also
had greater impact on NPK transformations in Alfisols.

Molecular identification of Araecerus fasciculatus and its endosymbiotic bacteria

2024-02-22T10:42:30+00:00

Araecerus fasciculatus are one of the important storage pests of cassava, associated with a wide variety of
bacterial endosymbionts that confer many ecologically relevant traits to the host insect. Endosymbiotic
bacteria (ESB) play a vital role even in the physiology of the host, hence identification of ESB associated
with the storage pests will help to develop important strategies for the management of the noxious
pest. In the present study molecular characterization of the Araecerus fasciculatus and endosymbiotic
bacteria associated with them, was done. By molecular characterization they were identified as Araecerus
fasciculatus and sequences were deposited at NCBI with accession no OR415335. Further, the genomic
DNA was isolated from each of the EPB isolates and PCR amplification of 16S rRNA gene was carried
out using universal primers. The 16S rDNA gene sequences of endosymbiotic bacterial isolates were
generated by sequencing the PCR product and were aligned with each other by using BioEDIT software.
The nucleotide sequences were compared with those in the NCBI databases using the Basic Local
Alignment Search and were identified as were confirmed as Bacillus megaterium. The taxonomy had been
recently changed and was renamed Priestia megaterium, which is a new separate genus from Bacillus. The
16S rRNA gene sequences were also deposited at NCBI database with accession no OR418413. From
the aligned sequences phylogenetic tree was constructed by the Neighbor-Joining method using MEGA
version 11.

Floral biology and its manipulation for successful breeding programs in cassava (Manihot esculenta Crantz) - A review

2024-02-21T09:07:15+00:00

Cassava is an important staple food of the tropical regions, and it fulfils the dietary requirements of
~900 million people. It is a strategic crop with climate resilience, wide adaptation to diverse climatic
conditions and has the potential to cope with the effects of climate change in the future. Cassava
is a cross-pollinated crop, pollinated mainly by honey bees. Speed breeding incassava is constrained
by its high levels of genetic heterozygosity, sparsely flowering nature of genotypes with high breeding
value and low seed set as well as seed germination. In India, cassava breeding was successfully carried
out during the last five decades through selection of profusely flowering genotypes, manipulation of
flowering in sparsely flowering genotypes using mechanical methods and hormonal treatment. There
is variation in flowering time (from 4 months to >eight months) and the number of flowers among
genotypes. Different genotype-environment interaction existed on flowering among varieties and a
strong environmental effect on the number of flowering peaks within the same variety was noticed.
Induction of flowering in erratic flowering types was done through pruning/de-topping of non
branching types and by grafting on to profusely flowering clones. Cryopreservation of pollen of sparsely
flowering genotypes was successfully undertaken to maximise the genetic recombination in cassava.
The present paper summarises the floral behaviour of cassava in different mating systems and artificial
induction of flowering and cryopreservation of pollen that was successfully used to develop hybrids,
inbreds and triploids in cassava.

Greater Yam: An overview of its phytochemical profile and potential for ensuring food security

2024-02-22T05:16:53+00:00

Millions of people in tropical nations rely on cultivated yams (Dioscorea spp.) as their main source of
nutrition. Even though these underutilized crops are rich in nutrients, there is a dearth of information
on them, which impedes their development and sustainability. Greater yam (D. alata) plant has medical,
pharmacological, cosmetic, and industrial uses in addition to its nutritional value. Their bioactive
components, which include anti-inflammatory, antibacterial, and antioxidant properties, have recently
drawn more interest in scientific investigations. This analysis aims to highlight the undervalued benefits
of yams for pharmacological applications and food security. These species differ greatly in their
morphology with regard to the length of growing season, the types of tubers produced, the dry matter
content of the tubers, and the nutritional and chemical components of the tubers. Nonetheless, there is
a dearth of knowledge currently available about yams. As a result, we covered information regarding the
botanical description, origin and distribution, genetic resource, agronomy, pharmacological properties,
nutritional values, molecular and genomic research, and future prospects regarding yams in this review