Development of Inbred Line in Parthenocarpic Cucumber (Cucumis sativus)
Botanical name: Cucumis sativus
Family: cucurbitaceae
Chromosome no: 2n=14
Origin: India
Introduction
Parthenocarpic cucumbers are hybrid plants and they produce fruit asexually and their main feature is they are seedless are have negligible seeds. There are certain reasons to produce hybrid seeds and some of these of their high yielding capacity, resistance against environmental conditions and due to high vigor. Cucumber is a cross pollinated and summer season crop. In tunnel best time for its sowing is the month of November. Production will start from the end of the month of February.
For the purposes of breeding like selfing or crossing we need the male flowers. To induce the male flowers chemical treatment is used. Chemicals like silver nitrate, cobalt and GA3 is used to induce the male flowers. By spraying the silver nitrate at the apical meristem silver ions interrupt the pathway of ethylene production that is responsible for female flowers production. This chemical application may also cause burning of tissues in case of dipping the apical portion. Generally 200-300ppm range is suitable for inducing the male flowering. Concentration depends on temperature in case of high temperature light concentration will also be effective. When we stop the chemical application plant again shifts towards female flower production.
Sex Types
There are five types in cucumber.
Gynoecious.
Special hybrids which predominantly produce female flowers.
Androecious.
Plants having only male flowers.
Andromomoecious.
Plants having both male and Hermaphrodite(bisexual)
Flowers both at different positions in one plant.
Hermaphrodite.
Plants having male and female flowers combine at same location.
Monoecious.
Plants having male and female flowers at different positions in one plant
procedure of pollination
We do three types of pollination in cucumber they are
selfing
In selfing male and female flowers of same plant are used .Petals of male flower are removed and anthers are rubbed on female flower. It is performed to produce advance hybrids.
sibing
In sibing male and female flowers are taken from same genotype but from different plants this is called sibing. Same procedure for pollination is used. Sibing is done to maintain the characteristics of certain genotype.
crossing
In crossing male and female of different genotypes are taken. For the development of inbred line in parthenocarpic cucumber crossing is avoided and it is mostly done by honey bee so known as entomophilus.
procedure
For inbred line development we have to recognize male and female flowers as female flowers have ovary at their base which is absent in male flowers .
- Male flowers are taken and petals are removed.
- Female flower is took which is healthy.
- Male flower is rubbed on female flower stigma and pollination is done.
- Than labels are tied to pollinated flowers.
- The name of female genotype is written first and then of male in case of crossing and in sibing and selfing only name of that genotype is written and at the end date is written.
Conclusion.
We follow pedigree method to produce hybrids in parthenocarpic cucumber. These have high market value due to its characteristics. But in future there is a need to use biotechnological methods to produce better hybrids than this conventional breeding methods .
Written by. Zeeshan Arif Wahla, Maria Riaz
