Progeny testing and genetic diversity analysis in plus trees of Melia dubia Cav.

Abstract

The present study titled “Progeny testing and genetic diversity analysis in plus trees of Melia dubia Cav.” was carried out from 2020 to 2021 with the objective of progeny evaluation in 25 half sib plus trees identified from different part of Kerala, by studying the growth performance of its seed progeny planted at college of forestry germplasm field. The study also includes exploring the genetic diversity of these 25 plus tree seed progenies along with analysing the caryophyllene content, one of the economically important phytochemical compounds present in M. dubia. The plus tree seed progeny differed significantly in morphological traits like height, collar girth, volume and physiological parameters like photosynthetic and transpiration rate, stomatal conductance, chlorophyll content and relative water content. The progeny FCV-MD-03 of Tholpetty in Wayanad district performed better in growth parameters viz., height (5.61 m), collar girth (0.42 m) and tree volume of (0.017 m3 ). The variability study indicated that the morphological trait (volume) and physiological trait (stomatal conductance) exhibited higher PCV and GCV. From the heritability estimation it was observed that the most heritable morphological trait was collar girth followed by the plant height. For the physiological parameter, transpiration rate (0.91) was the most heritable trait followed by the chlorophyll content. These morphological and physiological traits were positively correlated implicating the significance of physiological parameters as source to identify better progeny. Path analysis on morphological trait has showed that the collar girth had the highest positive direct effect on the plant volume. Genetic variation study in 25 plus tree progenies using ISSR primer produced 164 amplicons which estimates viz., percentage of polymorphism (68%), polymorphism information content (0.70 to 0.83), Nei’s gene diversity (31%). The dendrogram obtained by using UPGMA classified the 25 accession of M. dubia into 2 distinct clusters. Cluster I constitute population from Wayanad and the rest of the 136 population in cluster II. Based on the genetic variation observed, superior seed sources can be identified and tree improvement programme could be developed for the conservation and further development of M. dubia. Standardization of HPLC for the quantification of caryophyllene phytochemical in M dubia was studied. Significant variation was observed for the total caryophyllene content for the different accession of M dubia seed progeny. The maximum quantity was observed in FCV-MD-08 (16.4 %) of Pothundy in Palghat district followed by FCV-MD-3 of Tholpetty in Wayanad.