Leaf injury index: A quantitative approach for rapid screening of drought tolerance in citrus rootstocks

The present study was carried out during 2019–2021 at ICAR-Indian Agricultural Research Institute, New Delhi to observe leaf injury symptoms and number of functional leaves in nine citrus rootstock genotypes subjected to drought stress. The experiment was laid out in a completely randomized block d...

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Main Authors: AMRUT S MORADE, R M SHARMA, A K DUBEY, LEKSHMY S, D M KADAM, O P AWASTHI, A K MAHAVER, DEEPAK
Format: Article
Language:English
Published: Indian Council of Agricultural Research 2025-03-01
Series:The Indian Journal of Agricultural Sciences
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Online Access:https://epubs.icar.org.in/index.php/IJAgS/article/view/159082
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author AMRUT S MORADE
R M SHARMA
A K DUBEY
LEKSHMY S
D M KADAM
O P AWASTHI
A K MAHAVER
DEEPAK
author_facet AMRUT S MORADE
R M SHARMA
A K DUBEY
LEKSHMY S
D M KADAM
O P AWASTHI
A K MAHAVER
DEEPAK
author_sort AMRUT S MORADE
collection DOAJ
description The present study was carried out during 2019–2021 at ICAR-Indian Agricultural Research Institute, New Delhi to observe leaf injury symptoms and number of functional leaves in nine citrus rootstock genotypes subjected to drought stress. The experiment was laid out in a completely randomized block design (CRBD) with four replications. Qualitative leaf injury symptoms, namely yellow, rolled, scorched, defoliated leaves, and leaf wilting were used as weighted indicators after normalization. A composite weighted indicator-based index, the leaf injury index (LII) was then developed to evaluate the drought tolerance in citrus rootstocks. Citrus genotype RLC-2 exhibited the highest values for yellow (29.75), rolled (22.75), scorched (20.75) leaves, and leaf wilting score (4.50), while Grambhiri showed the highest defoliation count of 16.25. In contrast, X639 had the highest number of functional leaves (79.13) with lowest visible leaf injury in terms of yellow, rolled, scorched, and defoliated leaves, and leaf wilting score. The effectiveness of LII in measuring the drought sensitivity of citrus rootstock genotypes was tested using a heatmap and cluster analysis. Citrus genotype X639 was grouped into a single distinct cluster with the significantly lowest LII (0.250), indicating its drought tolerant nature. The other tested genotypes were classified into three sub-clusters: drought-sensitive (Cleopatra mandarin, RLC-2, RLC-1 and Grambhiri), intermediate drought response (RLC-7 and Troyer citrange), and some degree of drought tolerance (RLC-4 and RLC-5), with their higher, intermediate and lower LII respectively. This composite indicator ideally converts multiple qualitative indicators into a simple, rapid and cost-effective framework for screening citrus germplasm against drought stress.
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language English
publishDate 2025-03-01
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series The Indian Journal of Agricultural Sciences
spelling doaj-art-3c64310f4e1b4cefa31042833cfb48772025-08-20T03:49:45ZengIndian Council of Agricultural ResearchThe Indian Journal of Agricultural Sciences0019-50222394-33192025-03-0195410.56093/ijas.v95i2.159082Leaf injury index: A quantitative approach for rapid screening of drought tolerance in citrus rootstocksAMRUT S MORADE0R M SHARMA1A K DUBEY2LEKSHMY S3D M KADAM4O P AWASTHI5A K MAHAVER6DEEPAK7ICAR-Indian Agricultural Research Institute, New Delhi 110 012, IndiaICAR-Indian Agricultural Research Institute, New Delhi 110 012, IndiaICAR-Central Soil Salinity Research Institute, Regional Research Station, Lucknow, Uttar PradeshICAR-Indian Agricultural Research Institute, New Delhi 110 012, IndiaICAR-Central Citrus Research Institute, Nagpur, MaharashtraICAR-Indian Agricultural Research Institute, New Delhi 110 012, IndiaICAR-Indian Agricultural Research Institute, New Delhi 110 012, IndiaICAR-Indian Agricultural Research Institute, New Delhi 110 012, India The present study was carried out during 2019–2021 at ICAR-Indian Agricultural Research Institute, New Delhi to observe leaf injury symptoms and number of functional leaves in nine citrus rootstock genotypes subjected to drought stress. The experiment was laid out in a completely randomized block design (CRBD) with four replications. Qualitative leaf injury symptoms, namely yellow, rolled, scorched, defoliated leaves, and leaf wilting were used as weighted indicators after normalization. A composite weighted indicator-based index, the leaf injury index (LII) was then developed to evaluate the drought tolerance in citrus rootstocks. Citrus genotype RLC-2 exhibited the highest values for yellow (29.75), rolled (22.75), scorched (20.75) leaves, and leaf wilting score (4.50), while Grambhiri showed the highest defoliation count of 16.25. In contrast, X639 had the highest number of functional leaves (79.13) with lowest visible leaf injury in terms of yellow, rolled, scorched, and defoliated leaves, and leaf wilting score. The effectiveness of LII in measuring the drought sensitivity of citrus rootstock genotypes was tested using a heatmap and cluster analysis. Citrus genotype X639 was grouped into a single distinct cluster with the significantly lowest LII (0.250), indicating its drought tolerant nature. The other tested genotypes were classified into three sub-clusters: drought-sensitive (Cleopatra mandarin, RLC-2, RLC-1 and Grambhiri), intermediate drought response (RLC-7 and Troyer citrange), and some degree of drought tolerance (RLC-4 and RLC-5), with their higher, intermediate and lower LII respectively. This composite indicator ideally converts multiple qualitative indicators into a simple, rapid and cost-effective framework for screening citrus germplasm against drought stress. https://epubs.icar.org.in/index.php/IJAgS/article/view/159082Composite indicator, Drought response, Leaf wilting, Scorching, Senescence
spellingShingle AMRUT S MORADE
R M SHARMA
A K DUBEY
LEKSHMY S
D M KADAM
O P AWASTHI
A K MAHAVER
DEEPAK
Leaf injury index: A quantitative approach for rapid screening of drought tolerance in citrus rootstocks
The Indian Journal of Agricultural Sciences
Composite indicator, Drought response, Leaf wilting, Scorching, Senescence
title Leaf injury index: A quantitative approach for rapid screening of drought tolerance in citrus rootstocks
title_full Leaf injury index: A quantitative approach for rapid screening of drought tolerance in citrus rootstocks
title_fullStr Leaf injury index: A quantitative approach for rapid screening of drought tolerance in citrus rootstocks
title_full_unstemmed Leaf injury index: A quantitative approach for rapid screening of drought tolerance in citrus rootstocks
title_short Leaf injury index: A quantitative approach for rapid screening of drought tolerance in citrus rootstocks
title_sort leaf injury index a quantitative approach for rapid screening of drought tolerance in citrus rootstocks
topic Composite indicator, Drought response, Leaf wilting, Scorching, Senescence
url https://epubs.icar.org.in/index.php/IJAgS/article/view/159082
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