HRT512 – BREEDING OF FRUITS CROPS
LEARNING OUT COME REPORT OF PRACTICAL - 04
PANKAJ KUMAR - 12100476
Aim:- To study about floral character blossom biology and anthesis in subtropical fruit crops.
Pomegranate –
Punica granatum L.
Family – Punicaceae
It is one of the important fruit crops of the tropical and subtropical regions of the world. So
breeding in this fruit crop is of significant value and as the flowering habit of pomegranate is
influenced by prevailing climatic conditions, understanding of floral biology is very helpful
in crop improvement programme.
Flower bud development – it varies with times under tropical conditions. Depending upon
varieties and geographical conditions, time interval between flower bud elongation and
anthesis ranges from 14 to 28 days. In subtropics - Last week of March to second week of
May. Flowering season: There are two flowering season in North India and three in western
India due to the influence of climatic conditions.
Three different seasons are:
Ambe bahar (Jan-Feb)
Mrig bahar (Jun-Jul)
Hasth bahar (Sep-Oct)
Inflorescence: The inflorescence of pomegranate is known as Cyme (dichasial cyme).
Flowers appear on one year old (in evergreen cultivar) and current year’s growth (in
deciduous cultivar) on spur or short branches either solitary (along the branches), pairs, or
clusters (terminal).
Flowers: Flowers are short peduncle or subsessile. Sepals and petals are equal in number (5-
8). Multiple long stamens (>300 per flower) are inserted into the calyx walls. In-between
ovary and stamens nectarines are present. Carpals vary in number but generally are 8
superimposed in two whorls. During early balloon stages the flower look like a small pear.
There are three types of flowers:
Male flower are campa-nulate (bell shape)
Hermaphrodite are urce-rate (vase shape)
Intermediary (tubular shape)
Male flower has a rudimentary type of ovary and generally have THRUM type anatomy. The
intermediary flowers have degenerative type of ovary. Hermaphrodite is perfect flower with
well developed ovary with broad base. These flowers are of PIN type and pistil is either at
same level or at higher level then stamens. It favors selfpollination as well as by insects
(entomophily). These flowers produce regular shaped well formed fruits.
PIN and THRUM type anatomy of flowers is known as Heterostyly.
Cultivar having flowers with high petal number and dark colour are often used as ornamental
pomegranates and called as double flowered. This phenomenon of producing large attractive
rose like flowers due to phenomenon is called as Petaloidy. And stamens are modified into
petals. Generally they does not set flowers but produce fruit when pollinated with pollens of
cultivated pomegranate.
Anthesis: The first sign of unfolding of flower bud is the crack at the apex of the floral bud.
Time of anthesis varies with variety. In variety ‘Ganesh’ it commences at 7 am and finishes
at 6 pm. The maximum flower opening occurred between 10 am to 12 noon in most flowers.
Dehiscence of anthers generally takes place after opening of the flowers but sometimes it get
delayed by 2-3 hrs. It varies with varieties and sometimes occurs even before anthesis like in
case of ‘Patiala’. A temperature of 37 to 38˚C is optimum. Pollens of all the varieties are
highly fertile. Even though both hermaphrodite and male flowers produce viable pollens the
fertility of the pollen grains from hermaphrodite flowers is higher. In ‘Ganesh’ pollen
viability ranges between 84-95 %.
Stigma receptivity: Stigma matures one day before anthesis. Receptivity remains at peak on
the same and second day after anthesis but gradually decease until the third day after which it
abruptly becomes non-receptive. Protogyny (Maturation of the pistil occurs first) cause cross-
pollination in pomegranate.
Pollination: both self as well as cross pollination occurs in case of pomegranate. Cross
pollination increases the fruit set to 67.9% and is mainly affected by three insects, namely
Camponotus spp., apis spp. and Papilio demoleus. Wind pollination (anemophily) also occurs
in pomegranates.
Metaxenia: the immediate effect of foreign pollen on maternal/ovular tissue is referred as
metaxenia. Sometimes, several seeds of different colors occur within an individual
pomegranate fruit due to metaxenia.
