CYTOLOGICAL CHARACTERIZATION OF TOMATO (SOLANUM LYCOPERSICUM L.) GERMPLASM

Abstract

Germplasm diversity of any crop plays a significant role in the establishment of a successful breeding programme. In this study, five tomato germplasm, namely Roma Savannah, Tima, UTC, Dan Zaria and Tagino were collected from the Nasarawa State College of Agriculture, Lafia were evaluated for their cytological characterization to determine the germplasm cytological karyotyping parameters. The number of chromosomes in all lines was 2n = 24, except for Tagino, in which the number was 2n = 26, whereas chromosome sizes were small, ranging from 322.09 to 461.17µm. The Roma Savannah cultivar was a symmetrical cultivar (primitive), having the highest total form percentage (TF%) and symmetry index (Syi) values and the minimum karyotype asymmetry index (ASK) value, whereas Dan Zaria was asymmetrical (advanced) which makes it a superior germplasm among the other five evaluated. On the whole, the application of cytological techniques could be considered as a means to provide suitable parameters for studying the evolution of the genetic divergence between the studied tomato lines which can aid in preserving genetic resources in gene banks and improving new cultivars in breeding systems.