Polyembryony and morpho-genetic characterisation of zygotic seedlings through microsatellite markers in ten polyembryonic citrus rootstocks

Abstract

Morpho-genetic characterisation of zygotic and nucellar seedlings of 10 citrus rootstocks was carried out to know the degree of polyembryony. 'Volkameriana' rootstock had maximum fruit and seed weight. Polyembryony, number of embryos per seed and clutch size was highest in 'Katazamir'. However, the seeds of 'Schaoub' took minimum days to germinate while 'Cleopatra' took maximum days. Significant positive correlation was observed between percent polyembryony and average number of embryos per seed, seed weight and number of seeds per fruit. Twenty SSR primers were utilised for detection of zygotic seedling from all rootstocks. None of the individual primers used in this study were able to consistently identify zygotic seedlings in all rootstocks tested. The maximum (26.7%) zygotic seedlings were identified in 'Katazamir' and minimum (5.0%) in 'X-639' rootstocks. There was not a significant correlation between seedling height and zygotic and nucellar seedlings, identified with SSR markers. Therefore, seedling height cannot be taken as a criteria to identify the nucellar and zygotic seedlings.