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6 TYPES OF GERMPLASM MATERIALS (WILD FORMS & WILD RELATIVES (1.wild…
6 TYPES OF GERMPLASM MATERIALS
1.LAND RACES
these are nothing but primitive cultivars which were selected & cultivated by farmers for many generations
without systemic & substained plant breeding efforts
they are store house of genetic variability & adapted to the local soil type, climatic conditions
*more resistance to environment & have variation in genetic
WILD FORMS & WILD RELATIVES
1.
wild forms (WF)
are the wild sps from which crop sps were directly derived
2.they're easy to cross with the concerned crop sps
the
wild relatives (WR)
include all other sps, which are related to the crop sps by descent during their evolution.
WR
are more difficult to hybridize with crops than
WF
both of these group WR & WF are source of valuable genes for : insect & disease resistance,
tolerence to abiotic stresses &
even quality traits & yield
2.OBSOLETE CULTIVARS
defines as : Improved varieties of recent & past are known as obsolete cultivars
obsolete cultivars have several desirable characters they constitute an important part of gene pool
3.MODERN CULTIVARS / VARIETIES IN CULTIVATION
They currently cultivated high yielding varieties, referred to as modern cultivars
also known as improved cultivars or advanced cultivars
these varieties hv high yield potential & uniformity compared to obsolete varieties & land races.
a major part of working collections & are extensively used as parents in the breeding programs
4.BREEDING LINES
These are lines/populations developed in breeding program
hv narrow genetic base & contain valuable gene combinations
this group include nearly homozygous lines, mutant lines & lines derived from biotechnological approaches including transgenic lines
SPECIAL GENETIC STOCKS
This category includes lines carrying gene mutations, chromosomal aberrations, marker gene
Exp : A material will be set of monosomic lines ( when a diploid organism has only 1 copy of 1 of its chromosome instead of 2 ) OR trisomic lines ( 2n+1)- means that the affected person has 47 chromosome instead of 46 chromosome(normal)