Estelitta, SSaira Banu, V KKAU2019-05-272019-05-272001171804http://krishikosh.egranth.ac.in/handle/1/5810104916PGBanana is an important fruit crop of Kerala, which is commonly infected by yellow sigatoka leaf spot disease caused by Mycosphaerella musicola Leach. Investigations on anatomical and biochemical bases of resistance in . banana to yellow sigatoka leaf spot disease were carried out in the Dept of Plant Pathology and Biochemistry Laboratory of the College of Horticulture, Vellanikkara during 2000-2001. Severity of sigatoka disease was observed maximum 10 the peak monsoon month of July (cool moist period) followed by October (warm moist period) and April (warm dry period) and minimum in January (cool dry period). Maximum growth of M musicola was obtained in the medium potato glucose yeast extract agar (PGYEA) and poor sporulation in the medium banana dextrose agar (BnDA). Red pigmentation was observed in all media tried. The study revealed that the four different groups of banana differed significantly in the various anatomical and biochemical parameters. The resistant variety, Manoranjitham (AAA) was characterised by thickest cuticle and epidermis with inter mediate sized epidermal cells on the adaxial surface and denser pattern of epicuticular wax deposition on the abaxial surface of leaves. Thinner spongy and palisade tissues, maximum number of large and closely placed vascular bundles, thickest lower epidermis and decrease 10 number of stomata/unit area on the adaxial and abaxial surfaces of leaves. The highly susceptible variety, Grand Naine (AAA) showed thinner cuticle, thickened and large sized epidermal cells on the adaxial surface and faint pattern of epicuticular wax deposition on the abaxial surface of leaves. Less number of small and distantly placed vascular bundles, thicker spongy and palisade tissues and maximum number of stomata lunit area on the adaxial and abaxial surfaces of leaves. After pathogen infection the resistant variety Manoranjitham (AAA) showed partial disintegration of spongy mesophyll tissues and the highly susceptible variety Grand Naine (AAA) showed complete disintegration of chloroplast and mesophyll with necrotic vascular bundles. Stomata was found opened during day time and closed during night hours in both healthy and diseased leaves. In the biochemical parameters studied, the resistant variety, Manoranjitham (AAA) possessed higher quantities of total phenol, OD phenol, non reducing and total sugars, protein and peroxidase activity and intermediate values for proline and activity of polyphenol oxidase and lower quantity of reducing sugar. The highly susceptible variety, Grand Naine (AAA) was characterised by higher quantities of reducing sugar and intermediate values for total phenol, non reducing and total sugars and lower quantity of proline, protein, OD phenol and peroxidase and polyphenol oxidase enzyme activities. After pathogen infection, higher quantity of OD phenol, reducing sugar and activity of polyphenol oxidase enzyme was observed in the variety Manoranjitham (AAA) where the content of total phenol, non reducing and total sugars, proline, protein and activity of peroxidase enzyme decreased. The highly susceptible variety, Grand Naine (AAA) exhibited higher quantities of total phenol, reducing sugar, proline and higher activities of peroxidase and polyphenol oxidase enzymes and lower quantities of OD phenol, non reducing and total sugars and protein. The concentrated culture extracts of M musicola In seven different media gave different Rf values.ennullThesis