Studies on Genetic Divergence, Inter- Relationship And Their Implications in Genetic Improvement of Gladiolus (Gladiolus Llybridus Hort.) Germplasm

Abstract

Thesis Title: "Studies on genetic divergence, inter- relationship and their implications in genetic improvement of gladio Ius (Gladiolus hybridus Hort.) germ plasm". The present investigation was conducted to studies on genetic divergence, interrelationship among 53 gladiolus genotypes by using twenty seven morpho-agronomic traits. Analyzed data showed significant variation (p<0.05) among the germplasm for all traits indicating greater variability in germplasm. High genotypic coefficient of variation (27.03) and phenotypic coefficient of variation (32.45) were observed for weight of corms per plant. However, phenotypic coefficient of variation (PCV) was higher than genotypic coefficient of variation (GCV). Highest heritability (93 %) was recorded for weight of corm and higher heritability coupled with high genetic advance for weight of corm, weight of corms per plant, yield of corm per hectare and yield of corm and cormlets per hectare. The highest correlation coefficient at both phenotypic (0.99) and genotypic (1.00) level was found between yield of corm per hectare and yield of corm and cormlets per hectare. Yield of corm per hectare had highest positive direct effect (0.89 and 1.03) on the weight of corms per plant at both level. Mahalanobis 0 2 analysis revealed considerable amount of diversity in the germplasm. The genotypes were grouped into eight clusters. Cluster IV (13) and I (I 0) constituted maximum number of genotypes. The intra-cluster was maximum in cluster VII (02 = 372.852) reveals maximum genetic diversity followed by cluster II (02 = 343.392) and cluster V (02 = 150.904). The maximum inter cluster distance was observed between cluster VI1 and cluster VIII (02 = 1855.023) exhibited maximum divergence followed by, cluster II and VIII (02= 1568.477) suggesting that the genotypes constituted in these clusters may be used as parents for future hybridization programme. Since, the length of spike and yield of corms per hectare as recognized as yield attribute characters and the maximum mean value of these traits was observed in cluster VI and VIII respectively. 0 2 analysis suggested that quantitative characters showed higher value in different clusters need to be given more weightage, while selecting parents for improvements.