JOURNAL OF ROOT CROPS

Optimum potassium dose for K use efficient cassava genotypes in an Ultisol of Kerala, India

K. Susan John — 2025-11-04

Abstract
Mineral nutrition is one of the most important strategies to increase crop yields as plant nutrients are one among the critical factors contributing to higher productivity though the efficiency of the applied fertilizers is low. An alternative to this issue is the screening of nutrient use efficient (NUE) genotypes within a crop species which are unique with respect to their efficiency in acquisition, transport and utilization of nutrients. In this regard, the germplasm collection of cassava at ICAR-CTCRI was considered initially in 2008 for screening K use efficient genotypes. Preliminary evaluation of 83 elite genotypes for their physiological efficiency for K resulted in the identification of six genotypes viz., Aniyoor, 7 III E3-5, Sree Sahya, 6-6, CR 43-8 and W-19. These were tested under a split plot design with four levels of K viz., K₂O @ 0, 50,100 and 150 kg ha^-1 to select the most promising K use efficient genotypes as well as their optimum K application requirement. This paper describes the parameters viz., tuber yield and NUE parameters like agronomic efficiency, physiological efficiency, agro physiological efficiency, apparent recovery efficiency, utilization efficiency, harvest index, K harvest index, K utilization ratio/K utilization for tuber, K uptake ratio and K utilization for biomass considered over three years of experimentation under the above four levels of K in arriving the best level/optimum dose of K application for these genotypes. The above data revealed that all these genotypes performed best under K₂O @ 50 kg ha^-1 which was on par with either 100 and 150 kg ha^-1 K₂O elucidating the advantage of reducing the dose of K for these genotypes.

Keywords: Cassava genotypes, Nutrient use efficiency, K efficient, K uptake

Acclimatization of virus-free tissue culture plants of cassava through semi autotropic hydroponics technique

Iype Praveen Thomas — 2025-11-04

Abstract
Manihot esculenta Crantz, commonly known as cassava, belongs to the Euphorbiaceae family, and is a crucial tuber crop that serves as a staple food for millions of people worldwide. The acclimatization of cassava tissue culture plantlets faces challenges due to temperature, humidity and microfauna which leads to high mortality rate. To overcome these limitations, semi-autotrophic hydroponics (SAH) emerges as a promising technique for enhancing the large-scale production of cassava plants free from CMD and refining the process of acclimating in vitro plants to external conditions. This study aimed to evaluate the performance of cassava tissue culture plantlets using different substrates for rapid multiplication. Transplantation of in vitro nodal segments into three distinct growing substrates: cocopeat (CP), sawdust (SD), and sand (S) were tried in the experiment. These substrates were moistened with either Murashige and Skoog liquid solution or an experimental SAH solution for 60 days. The results showed that survival was significantly influenced by the substrate used, with cocopeat demonstrating the highest rate of more than 90%. The survival rate, shoot length, root numbers, and leaf numbers were collected at the end of one week. The differences in survival rates and growth parameters were significant among substrates (p<0.001).

Keywords: Cassava, Cocopeat, Saw Dust, Sand, Semi-Autotrophic Hydroponics (SAH)

Zeolite as a component of INM in enhancing nutrient mineralization and enzyme activities in an Ultisol

V. Ramesh — 2025-11-04

Abstract
In modern agricultural practices, there is a growing interest to optimize fertilizer usage to improve crop productivity and minimize environmental impact with special emphasis on soil carbon. In this study, the effect of slow-release fertilization characteristics of zeolites on soil carbon mineralization, enzyme activities and available NPK contents were investigated. A three month period incubation study at ambient temperature and constant soil moisture conditions was conducted in laterite soil with 27 treatments consisting of three commonly available organic manures (farm yard manure (FYM), vermi compost (VC), leaf manure (LM) and three different levels of near neutral zeolites, specifically the grade Zeolite 4A (@ 0, 1 and 2%, w/w) and fertilizer doses (@ 100% NPK, 75% NPK and 50% NPK corresponds to cassava crop with a recommended dose of 100:50:100 kg NPK per hectare). Addition of NPK fertilizers from 50% to 100% decreased the mean carbon mineralization activity and increasing levels of zeolites from 1% to 2% increased the carbon mineralization rates (3.39 as against 6.64 g CO2 per kg soil). Among the organic manures, leaf manure had higher carbon mineralization rate (5.70 g CO₂ per kg soil). The NPK @ 50% and 2% zeolite treated soils under vermi compost showed maximum activity of soil dehydrogenases (up to 42.99 ?g TPF g^-1 24 h^-1). Fertilizer and zeolite at 75% NPK and 1% doses respectively, registered the maximum acid phosphatase activity (1.258 ?g pnp g^-1h^-1). NPK fertilizers additions from 50% to 100% increased the soil available nitrogen content (127.97 to 136.67 kg ha^-1). Maximum content of mean available K was found with 50% NPK and 1% zeolite treatments.
Keywords: Zeolites, Carbon mineralization, Soil dehydrogenases, Organic manures

Mapping of women and men empowerment in Chinese potato cultivation in Tamil Nadu: A comparative analysis

D. Jaganathan — 2025-11-04

Abstract
The study mapped the profile characteristics, participation level and empowerment of women and men in Chinese potato cultivation in Tenkasi and Tirunelveli districts of Tamil Nadu. A simple random sampling technique was employed to select 132 respondents covering 66 women and 66 men and data were collected using structured interview schedule. Descriptive and inferential statistics were employed for data analysis. The study revealed that 37.88 percentage of men and 30.30 percentage of women had more than 20 years of experience in Chinese potato cultivation. Majority (87.88%) of the women cultivated Chinese potato in marginal farms of less than 2.5 acres. The mean participation score of women was 1.53 whereas for men it was 2.21. Women empowerment index in Chinese potato was estimated to be 0.55 and empowerment index for men was 0.80. It is suggested that women should be empowered by providing access to education, extension services, information, land, credit facilities, resources, and modern technologies in Chinese potato cultivation.
Keywords: Gender Analysis, Chinese potato, Women empowerment, Mapping

Inorganic fractionation of nitrogen, phosphorous and potassium as influenced by INM practices in elephant foot yam - black gram system

K. Laxminarayana — 2025-11-04

Abstract
A field experiment was conducted for two consecutive kharif seasons during 2018-19 and 2019-20 to study the effect of integrated application of inorganic fertilizers and organic manure on fractionation of N, P and K and yield performance of elephant foot yam – black gram cropping system in an acid Alfisol of Odisha. Higher amount of ammoniacal-N and nitrate-N (124.56, 24.19 kg ha^-1, respectively), reductant soluble-P (60.16 mg kg^-1) and exchangeable K (205.63 kg ha^-1) were recorded due to integrated application of FYM + ½ NPK. Available N in the soils influenced by ammoniacal N, nitrate-N and total N and the relationship was found to be positive and significant (r = 0.950**, 0.935**and 0.927**, respectively). Calcium bound P, total P, water soluble P, and Al-P contributed significantly towards the available P pool (r=0.991**, 0.955**, 0.942**, 0.930**, respectively), whereas, available K was contributed significantly with exchangeable K, total K and non-exchangeable K fractions (r = 0.979, 0.937** and 0.927**, respectively). Available N showed positive and significant relationship with starch, total sugars and dry matter (r=0.895**, 0.894**, 0.864**, respectively), whereas iron bound P had significant relationship with starch, total sugars and dry matter (r=0.869**, 0.832**, 0.686**, respectively). In conclusion, the corm yield of elephant foot yam and grain yield of black gram showed highly significant relationship with ammoniacal N, Fe-P and total K and they had been considered as major contributing fractions in respect of N, P and K towards the yield and quality of elephant foot yam – black gram crops.
Keywords: Alfisol, INM practices, Elephant foot yam, Yield, Quality, Inorganic fractions

Protocol optimization: A comparative study on phylloplane microbial recovery

S.A. Pavithra — 2025-11-04

Abstract
Elephant foot yam (Amorphophallus paeoniifolius), a herbaceous perennial crop utilizing the C3 photosynthetic pathway and belonging to the family Araceae, is cultivated extensively across eight
Indian states. Despite its numerous agronomic and economic benefits, the crop is vulnerable to several diseases. In recent years, symptoms such as yellowing of foliage, the appearance of various types of spots, and eventual partial or complete wilting have been increasingly observed. This disease, provisionally termed ‘leaf and pseudostem rot’, has been associated with the presence of more than three different pathogens. Investigating the crop’s microbiome, particularly the phylloplane, offers potential for use in biological disease management and may provide deeper insights into the complex etiology of the disorder.
In the present study, two protocols were evaluated for isolating phylloplane-associated microbes to determine which method could capture greater microbial diversity. The first protocol involved a single wash of leaf samples, followed by serial dilution and spread plating. The second protocol employed five successive washes of the leaf samples, after which the wash solutions were centrifuged to collect distinct pellets for bacterial and fungal isolation. These pellets were then serially diluted and cultured using dilutions up to 10-10. Results indicated that the second protocol was more effective, yielding a greater number and diversity of microorganisms compared to the direct aliquot method. The fungal and bacterial colony-forming units (CFUs) obtained using the first method were 2.0 × 10⁴ and 9.7 × 10⁵, respectively. In contrast, the five-wash protocol yielded 1.0 × 10⁵ fungal CFUs and 1.0 × 10¹⁰ bacterial CFUs. These findings suggest that the sequential washing and centrifugationapproach is more efficient for capturing the microbial diversity present on the leaf surface.
Keywords: Elephant foot yam, Phylloplane, Microbiome, Leaf yellowing, Leaf rot

Seed certification standards for quality planting material production of tannia [(xanthosoma sagittifolium (L.) schott]

R. Muthuraj — 2025-11-04

Abstract
Tannia [Xanthosoma sagittifolium (L.) Schott] is an edible aroid and a minor tuber crop belonging to the Araceae family which grows up to 2 m height with large and fleshy underground corm and cormels. Tannia starch is very important as they have many functional properties, which enhances the interest of the industrial sector in its production. Quality seed/planting material of released varieties is one of the most important determinants of tannia production, which influences the productivity and profitability. The efforts taken for several years may become futile, if true to type, healthy and disease-free quality planting material is not used. Therefore, quality of planting material of tannia with minimum seed certification standards assumes greater significance in the production of tannia for realizing higher yield and sustainable income in the long run. Seed certification standards covering general seed standards, land requirements, field inspection, field standards and seed standards have been developed for quality planting material production of tannia.
Keywords: Seed certification standards, Tannia, Planting material, Field standards

Determination of engineering properties of Chinese potato tubers (Plectranthus rotundifolius): Implications for designing a grading equipment

T. Krishnakumar — 2025-11-04

Biochemical changes in greater yam (Dioscorea alata) tubers at different stages of maturity

K. M. Lakshmi — 2025-11-04

Collar rot of elephant foot yam (Amorphophallus paeoniifolius): pathogen biology, detection, and management strategies – A review

S.S. Veena — 2025-11-04

Abstract
Tuber crops are increasingly recognized as important food security crops due to their resilience,adaptability, and contribution to household nutrition. Their cultivation is gaining popularity not only
because of their growing acceptance for culinary use but also for the income they generate for smallholder and commercial farmers alike. Among tropical tuber crops, elephant foot yam (Amorphophallus paeoniifolius) stands out as both a food security crop and a remunerative cash crop, especially in tropical and subtropical regions. However, the productivity and sustainability of elephant foot yam cultivation are significantly threatened by several diseases, primarily those caused by fungi and viruses. Notably,collar rot, mosaic, and leaf blight are the major diseases affecting elephant foot yam, with collar rot being the most common and devastating. Collar rot, caused by the soil-borne fungal pathogen Sclerotium rolfsii Sacc., leads to severe losses by attacking all stages of crop growth. Infections at the early vegetative phase can be particularly destructive, often resulting in total crop failure. The persistence of the pathogen in the form of hardy sclerotia and its broad host range complicate its management. The integrated disease management (IDM) strategy, which involves interventions from pre-storage through post-planting stages, has emerged as the most effective approach for combating S. rolfsii. Cultural practices, chemical treatments, bio-control agents, and organic amendments must be used in synergy to mitigate disease pressure and ensure yield stability. This review provides a comprehensive overview of collar rot disease in elephant foot yam, discussing the biology of the pathogen, symptomatology, disease epidemiology, and the economic impact, while highlighting advances in management practices, including cultural, chemical, biological, and integrated strategies.

Keywords: Elephant foot yam, Collar rot, Sclerotium rolfsii, Trichoderma, Integrated Disease Management