Differentiation of mixed flower buds in some traditional pear varieties in the region of Skopje

Ana Selamovska,Elizabeta Miskoska-Milevska

doi:10.5937/aaser1846277s

Abstract

The results in the present paper are part of the scientific research project 'Autochtonous genetic resources of pears in the Republic of Macedonia'. Flower bud differentiation was examined in five traditional pear varieties ('Carigradsko Avche', 'Letna Kajkushka', 'Vodenka', 'Zimska Kajkushka' and 'Zimnica') in the region of Skopje. In the region of Skopje, the differentiation of mixed flower buds in the traditional pear varieties starts in summer. The primordia of calyx and corolla are formed in the period from the second half of October to early November. In midNovember, stamen primordia are formed, while in late November the primordia of carpels are formed. In winter months, the archesporial tissue develops and microsporogenesis occurs. In the period from January to March, microgametogenesis and pollen grain development take place. The earliest differentiation of flower buds (approximately 7-10 days) and the earliest blooming (about 3-4 days) are tipical of the variety 'Carigradsko Avche', compared to the latest varieties 'Zimska Kajkushka' and 'Zimnica'.

Highlights

During its life, the flower bud passes through the so-called small, incomplete annual cycle, including the processes of transition from vegetative bud to the generative stage
Differentiation occurs in 4 phases: induction, initiation; differentiation and development of flower organs in the bud and the development of flower organs outside buds
The first visible sign of the transformation from the vegetative bud into the generative stage (IIIb substage) in the analysed pear varieties can be seen in July

Summary

Introduction

The flower bud passes through the so-called small, incomplete annual cycle, including the processes of transition from vegetative bud to the generative stage. It is part of the great cycle of ontogenesis. Under certain environmental conditions, in the armpit of the vegetative buds, meristem tissues transform into the generative stage. In the first year of vegetation, the bud occurs; in the second year the vegetative bud transforms into the generative stage; and in the third year blooming, fertilisation and ripening of fruits occur (Kuperman, 1968; Vitkovskii, 1984; Romanovskaya and Baksiene, 2007). The final stage of the ontogenesis cycle involves the formation and differentiation of flower buds. Differentiation occurs in 4 phases: induction ( occurring in the leaves after their emergence), initiation (physiological and chemical changes in the bud); differentiation and development of flower organs in the bud (internal invisible changes called microphenophases – I to VIII) and the development of flower organs outside buds (visible changes – phenophases IX to XII)

Methods

Results

Conclusion