STUDY ON EMBRYO DEVELOPMENT AND HYBRIDIZATION BETWEEN
BALADY AND CLEMENTINE MANDARINS
Abd El-Fattah Montasir Abd El-Salam Khedr
ABSTRACT
This study was carried out during 2004/2005 season and 2005/2006 season on
two cultivars of mandarin, Balady(Local)mandarin (Citrus reticulata) and Clementine
mandarin(Citrus clementina Blanco) at a private orchard located at Gharbia
Governorate to improve some characteristics of Balady mandarin through the
hybridization with Clementine mandarin and study the effect of hybridization on fruit
set, fruit retention, number of seed per fruit and germination percentage. Study the
stages of embryo development in Balady mandarin to know the dates of nucellar
embryo initiation through taking samples on stable dates after pollination (3 days) for
five months and make some anatomical studies. A primary determination on the
morphological characters was carried out for the seedlings from hybridization
between Balady and Clementine mandarins under plastic house and orchard
conditions such as seedling height, branches number, Leaves number and Leaf area.
The results confirmed that the final fruit set % in 2005-2006 season was 4.6%
while in 2006-2007 season, the final fruit set was 4.9 %.
Germination percentage data in 2005/2006 season showed that the germination
commenced after 26 days after planting under plastic house conditions .The
accumulated seed germination number for 2005/2006 season was 38 , while in
2006/2007 season was 56.
There was a variability in the morphological characteristics of seedlings under
the plastic house and the field conditions. The noticed differences in the seedling
heights, leaves number and branches number under plastic house conditions as well as
under field conditions indicate that there is a possibility of being due to genetic factors
beside the environmental conditions. Also, there was variation in leaf area between
seedlings from the hybridization between Balady and Clementine mandarin, such
variations indicate differences abilities of the trees for the photosynthesis process,
consequently sexual other growth and developmental factors will be affected.
Moreover, anatomical studies indicated that the nucellar embryo initiated in
early stages of embryo development. However, it was found that the sexual embryo
has a suspensor, while this is not present in the nucellar embryos. Thus this could be
used as sign to select and separate the sexual embryo under the microscope and
growing it under tissue culture condition to complete its growth and obtain hybrid
seedlings.