STUDIES ON GENETIC DIVERSITY IN AVOCADO Persea americana Mill

Abstract

newlineAuthor : AWACHARE CHANDRAKANT MADHAV newlineTitle of the thesis : STUDIES ON GENETIC DIVERSITY IN newlineAVOCADO (Persea americana Mill.) newlineDegree to which itis newlinesubmitted newline: DOCTOR OF PHILOSOPHY newlineFaculty : HORTICULTURE newlineDepartment : FRUIT SCIENCE newlineMajor advisor : Dr. G. KARUNAKARAN newlineUniversity : Dr.Y.S.R. HORTICULTURAL UNIVERSITY newlineYear of submission : 2023 newlineABSTRACT newlineThe present investigation entitled Studies on genetic diversity in avocado newline(Persea americana Mill.) carried out at ICAR IIHR Central Horticultural newlineExperiment Station, Chettalli during the years 2020-21 and 2021-22, in 72 avocado newlineaccessions to assess information on morphological and biochemical characters and newlineto determine the relationship between different characters through character newlineassociation studies and genetic divergence analysis. The study also focused to newlineassess the extent of genetic diversity at molecular level using SSR markers to test newlinethe reliability of marker technology. newlineThe 72 avocado accessions were characterized for 25 qualitative newlinemorphological traits by using IPGRI descriptors. The results showed vast diversity newlineamong the accessions, of which 2 characters had dimorphic and remaining 23 newlinecharacters had polymorphic in nature. The majority of accessions confronted with newlineobovate fruit shape (26.38 %), depressed fruit base (48.61 %), high uniformity in newlinefruit size (73.61 %), no ridges on fruit (59.72 %) and asymmetric apex position newline(59.70 %). Peel traits revealed the dominance of light green fruit colour (37.50 %) newlinewith smooth peel surface (51.38 %) among the accessions compared to rough peel newlineand other fruit skin colors. The pulp characters showed high values for buttery pulp newline(90.27 %), low bitterness of the pulp (54.16 %) and good general taste (54.16 %). newlineThe studies on genetic divergence viz., cluster analysis and PCA exhibited the newlineexistence of wide diversity among studied accessions for morphological newlinecharacters. PCA results showed that 25.39 % of the total variance in first three newlinecomponents and traits viz., peel adherence to pulp, pulp