Agriculture Reference
In-Depth Information
1.5 BIOTECHNOLOGY
A rapidly changing climate will require rapid development of new variet-
ies of fruits, vegetables and flowers that are capable to withstand vaga-
ries of the weather. As an adjunct of the well-established conventional
approaches of plant breeding, biotechnology can enhance the speed, flex-
ibility and efficiency of developing new hardy cultivars. Important contri-
bution of plant biotechnology would be to improve stress tolerance traits
in fruits, vegetables and other crops of commercial value in horticulture.
Molecular markers are used to provide greater focus, accuracy and speed
in crop breeding programs. In general, the opportunities for enhancing
crop performance under stress conditions lie in identifying key traits that
require enhancement, stress-relieving candidate genes and the appropriate
plant stage of development where enhancement should occur. This process
of gene identification and gene expression patterns associated with quan-
titative genetic traits in crops is becoming more attractive and promising
as the scientific community develops and gains access to large-scale ge-
nomics resources such as EST (expressed sequence tag) databases, high-
throughput gene expression profiling technologies and genomic mapping
information. In recent past stress tolerance of plants has been improved
through gene transfer, or at least identifies cases in which genetic engi-
neering of plants has shed some light on the mechanisms by which stress
tolerance or resistance is conferred.
Further, to improve the ability of crops to cope with existing and new
stresses, it is imperative to develop a basic understanding of the mecha-
nisms and processes by which plants respond to biotic and abiotic stresses.
Many of the major abiotic stresses arise because of a common biochemical
phenomenon, efforts to improve tolerance to one abiotic stress have poten-
tial to confer tolerance to other abiotic stresses. Research stations working
on horticultural crops are maintaining a large number of germplasms of
their mandate crops. They can help in breeding strains resistant to biotic
and abiotic stresses. Cryopreservation i.e. storage of tissues, for example,
meristem, embryo or recalcitrant seeds, etc. in liquid nitrogen at 196 °C
has been adopted for storage of germplasm and to ensures safety of rare or
endangered plant spp. This type of storage arrests all metabolic activities
resulting in storage of material for a longer time.
In the past two decades, more emphasis has been given to modifying
crops with stress tolerance-conferring genes. These efforts have demon-
