Diversity assessment and selection of candidate plus trees of ailanthus triphysa (Dennst.) alston in selected districts of northern Kerala

Abstract

Matti (Ailanthus triphysa [Dennst.] Alston), belonging to the family Simaroubaceae is a medium to tall evergreen rainforest tree. It is one of the most important and extensively used trees for making match splints in India. The study attempted to determine the diversity and select candidate plus trees from selected districts of Northern Kerala and to evaluate their progeny. Thirty candidate plus trees were selected based on baseline regression of trunk volume to crown volume combined with scoring for qualitative characters. The tree height, GBH, crown diameter and clear bole height of the plus trees varied from 20 m to 37 m, 0.69 m to 2.11 m, 3.5 m and 9.75 m and 7 m to 24 m respectively. The thirty candidate plus trees were grouped into nine clusters through cluster analysis. Cluster I had a maximum number of CPTs with 15 accessions, whereas the least number observed for cluster VII, VIII and IX respectively. Clusters with only one plus tree can either possess superior or inferior quality among the plus trees. The clustering pattern revealed that plus trees from the same geographic sources were grouped into different clusters, while plus trees from different geographic sources were grouped into the same clusters. The highest intra and inter cluster was observed on cluster I (2.07) and cluster III and IV (8.91). This indicates there was greater genetic distance within and between the clusters. Seedling biometric observations for different morphological and physiological characters showed significant differences except for the height of the seedlings. The seedlings height, collar diameter, the number of leaves and biovolume ranged from 8.73 cm (FCV-AT-02) to 11.2 cm (FCV-AT-01), 0.14 mm (FCV-AT-02) to 0.25mm (FCV-AT-16), 4.33 (FCV-AT-02) to 6.53 (FCV-AT-20) and 0.12 cm3 (FCV-AT-02) to 0.32 cm3 (FCV-AT-16). The progenies FCV-AT-21, FCV-AT-33, FCV-AT-36, FCV-AT-37, FCV-AT-39 and FCV-AT-40 were found superior based on overall mean performance of the morphological characters. Hence, seeds of these CPTs can be used in immediate field planting operations. The genetic analysis of the causes of variation for the morphological and physiological traits was studied. The highest phenotypic and genotypic coefficients ii of variation were observed on the character biovolume. For all the characters studied, the phenotypic coefficient of variation was higher than the genotypic coefficient of variations indicating that there were non-additive effects. High heritability coupled with a genetic gain was observed in the number of leaves and collar diameter. Similarly, heritability was high for all the physiological traits with an adequate genotypic variation that can help in the further improvement programme. The correlation studies on morphological and physiological studies showed that positive correlation was observed in the seedlings height and collar diameter of the CPTs. The relation with collar diameter and biovolume, collar diameter and stomatal conductance, biovolume and stomatal conductance of the CPTs were also found positive. A positive correlation was also recorded on the plus trees selected on the characters photosynthesis and transpiration and stomatal conductance and leaf temperature. It can be concluded from the study that considerable morpho-physiological variations exist in selected candidate plus trees of Ailanthus triphysa. These results could help in the future breeding programme as well as efficient management of the trees.