Browsing by Author "Sabana, A.A."

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    Development of EST‑SSR markers for genetic diversity analysis in coconut (Cocos nucifera L.)
    (2020) Preeti P; Shafeeq Rahman; Naganeeswaran, S.; Sabana, A.A.; Gangaraj, K.P.; Jerard, B.A; Niral, V.; Rajesh, M.K.
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    Inter-specific hybrids in Areca spp.: Verification using SCoT markers
    (2024) Rajesh, M.K.; Nagaraja, N.R.; Sabana, A.A.; Muralikrishna, K.S
    Disease resistance has been a major goal in crop improvement programmes in arecanut (Areca catechu L.), where the fruit rot disease or Mahali, caused by Phytophthora meadii, is a major production constraint in India. The wild Areca spp., such as A. triandra and A. concinna, have been reported to possess resistance to P. meadii. Developing inter-specific hybrids between A. catechu and A. triandra or A. concinna could be one of the strategies to introgress the disease-resistant trait from the wild Areca spp. into cultivated arecanut. In this study, we report the utilization of start codon targeted (SCoT) markers to differentiate A. catechu from A. triandra and A. concinna and the development of sequence-characterized amplified region (SCAR) markers to enable authentication of true inter-specific hybrids between them. The technique would effectively verify inter-specific hybrids at the seedling stage itself.
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    Multi-gene phylogeny and phenotypic analyses revealed an association of different Colletotrichum species with inflorescence dieback and leaf spot of arecanut in India
    (2024) Prathibha, V.H.; Rajesh, M.K; Akshay Dinesh; Balanagouda Patil; Daliyamol; Nagaraja, N.R.; Rajkumar; Sabana, A.A.; K.P. Gangaraj; K.P. Thejasri; Sunil S. Gangurde; Vinayaka Hegde
    Arecanut is one of the economically important plantation crops. Among the various diseases, inflorescence dieback and leaf spot/blight diseases caused by Colletotrichum spp. have re-emerged as major factors impeding arecanut production in India in the last few years. To understand the Colletotrichum species complex in the arecanut system, we have characterized Colletotrichum spp. associated with inflorescence dieback and leaf spot/ blight of arecanut based on a combination of phenotypic, multi-locus (ITS, ACT, CHS-1, GAPDH, HIS3 and TUB2) phylogeny and pathogenicity studies. A total of 26 Colletotrichum isolates were obtained from arecanut inflorescence dieback (13 isolates) and leaf spot/blight (13 isolates) infected tissues collected from disease-endemic regions of Karnataka, Kerala and Tripura states of India. The combined multi-locus sequence analyses and a critical examination of phenotypic characters revealed the association of Colletotrichum aoteaora as a dominant species with arecanut inflorescence dieback disease. On the other hand, two Colletotrichum species, viz., C. siamense and C. fructicola, were distinctly associated with leaf spot/blight disease. All the Colletotrichum isolates studied were pathogenic to arecanut. Significant variations in lesion size were observed among the different species with cross-infection ability on inflorescence and leaves. This study represents the first comprehensive study of Colletotrichum spp. associated with arecanut inflorescence dieback and leaf spot/blight diseases. In addition, the study is the first record of C. aoteaora, C. siamense, and C. fructicola associated with the arecanut crop in this country. It provides valuable information for implementing effective IDM strategies against these diseases in India.
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    New report on the invasive Bondar's Nesting Whitefly (Paraleyrodes bondari Peracchi) on oil palm in India
    (2024) N. B. V. Chalapathi Rao; B. S. Ramani; B. V. K. Bhagvan; Sabana, A.A.; Rajesh, M.K.
    This communication is the new report of the neotropical invasive Bondar's Nesting Whitefly (BNW) , Paraleyrodes bondari Peracchi (Hemiptera: Aleyrodidae)incidence in oil palm in India. A typical feature of BNW infestation is the presence of woolly wax nests on the abaxial surface of oil palm leaflets. The nesting whitefly population was observed to increase phenomenally on oil palm and within a year ie., from 2021 to 2022, a 100 per cent palm infestation was observed. During this period the intensity per palm increased by 24.49 per cent and per leaf increased by 63.28 per cent. Analysis of the partial mitochondrial cytochrome oxidase subunit 1 (CO1) sequences from adult specimens indicated 100% nucleotide identity with Bondar's Nesting Whitefly from coconut