COMPARATIVE ASSESSMENT OF GENETIC DIVERSITY IN CYTOPLASMIC AND NUCLEAR GENOME IN IMPROVED GOSSYPIUM HIRSUTUM AND G. BARBADENSE COTTON LINES FROM DIVERSE GEOGRAPHICAL LOCATION

Abstract

Breeders normally select genotypes based on morphological characters, primarily regulated by the nuclear genome. However, cytoplasmic genome, including mitochondria and chloroplast genomes, also play an important role to perform a number of biological functions in cotton breeding. The characteristics and the mode of genetic inheritance of cytoplasm and nuclear genome provide complementary valuable information to study gene flow, evolution, and population history. The study is aimed to develop cytoplasmic DNA markers as a tool for genetic research and to use the DNA markers as a tool to detect genetic variation in the cytoplasmic and nuclear genome in a set of G. hirsutum and G. barbadense lines. The study involved 61 SSR primer pairs associated with important fibre-specific traits of the nuclear genome and 49 indel and SSR primers specific to the cytoplasmic genome to screen 20 G. hirsutum and 74 G. barbadense lines from diverse geographical locations. It showed that cytoplasmic indel markers are more polymorphic compared to the cytoplasmic SSR markers among the lines. The overall results showed that the selected 94 lines could widely be divided into two broad groups G. hirsutum and G. barbadense. The research for the first time provided a genetic tool to study cotton cytoplasmic genome and a report comparing the genetic diversity in the cytoplasmic and nuclear genomes of G. barbadense and G. hirsutum lines. The following research will help breeders to develop a breeding strategy maximizing the effects of genetic diversity to improve cotton lines.