Physiological and anatomical alterations in wilting of guava (Psidium guajava L.) trees and its amelioration using ethylene inhibitor

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dc.contributor.advisorBrar, J.S.
dc.contributor.authorNaik, Eslavath Khamdar
dc.date.accessioned2023-12-29T15:07:41Z
dc.date.available2023-12-29T15:07:41Z
dc.date.issued2023
dc.description.abstractThe guava wilt disease is the foremost threat for guava cultivation not only in India, but also in all major guava growing countries. Hence; the present investigation was planned to get definite information on physiological, anatomical and biochemical aspects involved in this malady so that the consequent amelioration strategies may reoriented. In the present investigations, the comparative analysis of wilt affected and healthy plants were carried out over the developmental period and found significant alterations in physiological, anatomical, biochemical characteristics. Complete mortality of wilt affected trees was recorded within six months of symptoms development at all three locations. With the objective of amelioration strategy, CoCl2 with was sprayed at varied concentrations {0: ppm (wilted control), T2: 50 ppm, T3: 100 ppm, T4 :150 ppm and T5: water spray (healthy control)} at three distinct locations (L1, L2, L3). The treatments of CoCl2, resulted stability with respect to biochemical and physiological changes in plants during initial days and plants were able to survive and consequent improvement all the parameters was observed with the onset of spring season and new flush. Among all treatments CoCl2 @ 150 ppm was more effective for increasing leaf area index, leaf density, leaf thickness, ascorbic acid, leaf water content, though the lower concentration of 50 and 100 ppm were found effective. To confirm the pathogenicity in guava wilt disease, two-year-old guava plants, planted in 26-inch cemented pots were subjected to repeated fungal inoculation (Fusarium solani) with and without stem as well as root injuries singly and in combinations. The results revealed that the fungal inoculations in the rootzone of the plants could not affect the plants, whereas, the inoculation along with root and root+stem injury resulted about 90 % mortality of plants, which was again confirmed by isolating the culture from the shoot tips of the plants. Similarly, in our last experiment, 90 experimental trees exhibiting wilt symptoms were tagged and subjected to different treatments to assess the physiological, anatomical, biochemical, nutritional, fruit yield and quality parameters. The observations recorded on 0, 30, 90, 180 and 300 days revealed significant improvement in plant growth and developments after 90 days of application and values rises significantly the end of observation period (180 to 300 days) and plants resumed the growth as normal. Among all treatments, T4 (150 ppm @CoCl2) followed by T3 (100 ppm @ CoCl2) and T2 (50 ppm @ CoCl2) gave promising results for pigment levels, photosynthetic rate, canopy volume, leaf area index, leaf density and root density. Biochemically, maximum improvement in treated trees was recorded after 180 days of treatments. Data on ethylene and auxin exhibited significant rise in the excised leaves of both wilted and healthy plants initially followed by decline after 8 hours, but at faster rate in wilted plants. From the investigations, it may be inferred that the pathogens are not a primary cause of guava wilt disease. The mechanical root injury or other abiotic stress factors acts as a primary cause to makes the plants prone to be attacked by the pathogen infections. Triggered ethylene level and consequent amelioration of wilting plants using ethylene inhibitor corroborated the hypothesis of investigations.
dc.identifier.citationNaik, Eslavath Khamdar (2023). Physiological and anatomical alterations in wilting of guava (Psidium guajava L.) trees and its amelioration using ethylene inhibitor (Unpublished Ph.D. Dissertation). Punjab Agricultural University, Ludhiana, Punjab, India.
dc.identifier.urihttps://krishikosh.egranth.ac.in/handle/1/5810205011
dc.keywordsGuava
dc.keywordsFusarium sp.
dc.keywordsEthylene
dc.keywordsAuxin
dc.keywordsCobalt chloride
dc.keywordswilt symptoms
dc.language.isoEnglish
dc.pages188
dc.publisherPunjab Agricultural University
dc.research.problemPhysiological and anatomical alterations in wilting of guava (Psidium guajava L.) trees and its amelioration using ethylene inhibitor
dc.subFruit Science
dc.themePhysiological and anatomical alterations in wilting of guava (Psidium guajava L.) trees and its amelioration using ethylene inhibitor
dc.these.typePh.D
dc.titlePhysiological and anatomical alterations in wilting of guava (Psidium guajava L.) trees and its amelioration using ethylene inhibitor
dc.typeThesis
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